APART Study Guide for the Army Aviator

Current as of 20 February 2001

http://apachestudy.homestead.com

Purpose: The purpose of this study guide is to assist the aviator in preparing for the APART evaluation and in maintaining currency and proficiency in the volumes of information required of today's aviator.  It is laid out identically to TC 1-214 (Aviator’s Training Manual, AH-64).  THIS IS NOT YOUR REFERENCE!  For those of you who read too quickly, I will say that again…THIS IS NOT YOUR REFERENCE!  This study guide is not complete and all encompassing, rather it is intended to add a “boost” to your memory and shake out the cobwebs that have built up since your last APART.  The references for each section of the ATM (TC 1-214) are listed beside each topic, are included on this CD, and it is HIGHLY encouraged that you pay a visit to the reference to learn more.  Some sections contain no information, as the volume is too much for me to include here.  Use of this study guide should not replace going to the reference for knowledge…

Standards: Evaluations are conducted to determine your ability to perform assigned duties. Orally, you must demonstrate a working knowledge and understanding of the subject areas listed in your ATM. These include:

1. REGULATIONS AND PUBLICATIONS: You must be familiar with the airspace classification system, recognize chart depiction of the various classes of airspace, and know when and how you can operate in the different classes; to include weather, equipment, and communication requirements. Also be familiar with the unit SOP as it pertains to your flying duties, your individual (CTL) training requirements (found in your IATF…ask your IP), weight and balance requirements, ALSE, inadvertent IMC procedures, flight restrictions due to exogenous factors, and interpretation of FLIP material.

2. OPERATING LIMITATIONS AND RESTRICTIONS: You must know the safe operating limitations of your aircraft.  You must also know what to do if limitations are exceeded. This area covers not only systems limitations, but flight envelope and environmental limitations and interpretation of performance charts as well.  See Chapter 5 of the UH-60A, UH-60L, and EH-60A -10 or Chapter 5 of the UH60Q -10.

3. AIRCRAFT EMERGENCY PROCEDURES AND MALFUNCTIONS: You must know how to properly deal with emergency procedures.  UNDERLINED PROCEDURES MUST BE COMMITTED TO MEMORY. Be prepared to discuss all procedures with emphasis on understanding the aircraft systems and flight characteristics during an emergency. Other areas of interest here include interpretation of Caution/Warning lights, after-emergency actions, emergency equipment and emergency exits.  See Chapter 9 of the UH-60A, UH-60L, and EH-60A -10 or Chapter 9 of the UH60Q -10.

4. AEROMEDICAL FACTORS: Be familiar with the various physiological hazards to flight. Be prepared to discuss contributing factors, symptoms, alleviation and avoidance, and regulatory restrictions.

5. AERODYNAMICS: Have a good working knowledge of aerodynamics and how it affects performance, flight characteristics, flight envelope and maneuvering limitations.

6. ATTACK HELICOPTER TACTICAL AND MISSION OPERATIONS: Be prepared to discuss and/or perform any and all of your CTL-designated mission tasks, as well as all base tasks listed in your ATM. Consideration should be given to terrain flight safety and terrain flight mission planning.

7.  MISSION AVIONICS OPERATION AND DEPLOYMENT :

8.  WEAPON SYSTEM OPERATION AND DEPLOYMENT:

9.  NIGHT MISSION OPERATION AND DEPLOYMENT:

10.  MAINTENANCE TEST FLIGHT TROUBLESHOOTING AND SYSTEM OPERATIONS:  See the UH-60A, UH-60L, and EH-60A MTF Manual or the UH60Q MTF Manual.

The flight evaluation consists of briefing, preflight, start and run-up procedures, flight tasks, and after-landing tasks. The briefing should cover, as a minimum, those items listed in TC 1-214, page 8-11, “Briefing”.  You will be evaluated on your use of the checklist for preflight, start and run-up, and shutdown. Also during preflight, you will be asked to identify at least two aircraft components and two weapon system components and discuss their functions. The flight itself will consist of evaluation of, as a minimum, those tasks listed in Ch. 8 (and listed below) and on the CTL as being mandatory for the evaluation being given. Please note that TC 1-214 states that the -10 test is part of the standardization eval and should be done before the flight.  Obtain a copy before your scheduled ride and bring it in completed.

Major areas outlined for oral examination in the ATM include:

(1) REGULATIONS AND PUBLICATIONS (ARs 40-8, 95-1, 95-2, DA Pam 738-751, DOD FLIPS, FM 1-240, TC 1-210, and local SOPs and regulations.)

(a) ATP requirements. Refers to your Commanders' Task List. Be familiar with your flying hour and task iteration requirements, evaluation requirements, and, if applicable, RL progression requirements.  You’ll find all this information in your IATF.

(b) SOP requirements. Be prepared to discuss your unit SOP, particularly as it pertains to your flight duties.

(c) DOD FLIP and maps. Be familiar with chart symbology and be able to interpret information in supplements. DA Pam 738-751 requires that the following be aboard the aircraft: -10 CL w/ changes, -10 cl changes, current 365-4 weight & balance, log book binder w/ HIT log, PMD checklist, 2408-4, -12, -13, -13-1, -13-2, -14, and -18, DD Form 1896 (Identaplate), and appropriate FLIP for the flight.

(d) VFR minimums and procedures. Aviators should recognize the various classes of airspace and the associated weather, equipment, and communications requirements. AR 95-1 states that before beginning a flight, aircrews will acquaint themselves with mission, procedures, and rules. A 20-minute fuel reserve is required for VFR flights, and, above 3000', semi-circular cruising altitudes apply. Minimum enroute altitude is 500' AGL (1000' over any congested area). Over-the-top flights (VFR) may not exceed 30 minutes duration unless the aircraft and crew are fully IFR legal and equipped. When converging, right-of-way rules give the right-of-way to the aircraft on the right. If approaching head-on, both aircraft should alter course to the right. If overtaking, you should pass to the right and remain well clear (the aircraft being overtaken has the right-of-way). When operating in the vicinity of an airport, helicopter pilots should avoid the flow of fixed-wing traffic.

1. Uncontrolled Airspace (Class G): This airspace generally extends from the surface to 1200' AGL (or 700' in transition areas shaded in magenta on sectional charts). It could extend as high as 14,500' in some areas. The FAA says a helicopter may be operated clear of clouds in Class G airspace (below 1200' AGL) as long as the helicopter is "operated at a speed that allows the pilot adequate opportunity to see any air traffic or obstructions in time to avoid collisions." Above 1200', helicopter operation requires I mile visibility day (3 at night) and cloud clearance of 500' below any cloud, 1000' above, and 2000' horizontally. Local SOP requires a minimum of 500' ceiling and 1 mile visibility for all VFR operations. So, when operating in Class G airspace, a Washington National Guard aviator requires a 500' ceiling, 1 mile visibility and, if above 1200' AGL, basic cloud clearance and 1 or 3 miles visibility for day and night, respectively.

2. Controlled Airspace. The FAA governs the weather minimums we have in controlled airspace. To maintain VFR in controlled airspace (Class C, D, and E), we must have minimum cloud clearances of 500' below, 1000' above, and 2000' horizontal. In Class B airspace, remain clear of clouds. In all cases, visibility minimum is 3 miles (Visibility and cloud clearance requirements increase above 10,000'). VFR is not permitted in Class A airspace (See accompanying chart showing U.S. airspace classification). Except when operating special VFR, you may not operate VFR beneath a ceiling within the lateral boundaries of controlled airspace (B, C, D, or E) designated for an airport when the ceiling is less than 1000'. Aviators may file flight plans to a destination within Class B, C, D and E airspace when weather conditions are forecast to be equal to or greater than known special VFR minima for that airspace at ETA through 1 hour after ETA. (AR 95-1). SVFR at SAAF is 300 and 1/2 day, 500 and 1 night.  Aviators will comply with the weather minimums established for the airspace in which they're operating.

(aa) Class A Airspace: All airspace above 18,000' MSL. VFR is not permitted.

(bb) Class B Airspace: Generally, that airspace from the surface to 10,000 feet MSL surrounding the nation’s busiest airports in terms of IFR operations or passenger enplanements.  The configuration of each Class B airspace area is individually tailored and consists of a surface area and two or more layers (resembling an upside-down wedding cake). Mode C required within 30 miles of primary airport. Specific clearance to enter is required. Note that cloud clearance requirements have been reduced to clear of clouds.

(cc) Class C Airspace: As depicted on charts, generally a 10-mile ring around airports with towers and approach controls, from the surface to 4000' above the airport. Two-way communication and Mode-C transponder are required for operation within Class C airspace. Mode C is also required for operations above Class C airspace.

(dd) Class D Airspace: Depicted as a segmented blue line on charts, generally a 5 statute mile circle around airports with operational control towers, with vertical limits shown in hundreds of feet. Radio communication is required for all aircraft operating within Class D airspace, regardless of destination. VFR minimum weather in Class D airspace is 3 miles visibility, cloud clearance of 500' below clouds, 1000' above, and 2000' horizontal.

(ee) Class E Airspace: 'Other' controlled airspace, to include non-tower instrument airfields, 700' and 1200' transition areas, federal airways, and airspace above 14,500' MSL.  Basic VFR visibility and cloud clearance requirements apply, but there are no specific communications requirements.  Mode C is required above 10,000' MSL.  Non-tower instrument airfields are depicted by a segmented magenta line indicating controlled airspace starts at the surface.  Arrival extensions for Class D airports may also be indicated in magenta, indicating that controlled airspace starts at the surface, but there are no communications requirements until penetrating the segmented-blue-line Class D airspace.

(ff) Prohibited Area: No flight permitted.

(gg) Restricted Area: Flight into Restricted Areas, while not wholly prohibited, may be extremely hazardous. Know why the restriction applies and/or who to contact.  Military pilots operating within restricted areas should adjust their transponders to code 4000 or as directed by the controlling agency.

(hh) Warning Area: Similar to Restricted Area, established in international airspace.

(ii) Military Operations Area (MOA): Areas in which low-level, high-speed, acrobatic flight is permitted by military aircraft. Pilots operating VFR in a MOA should exercise extreme caution.

3. Local Airspace Usage.  See XVIII Airborne Corps SOP and Fort Bragg 95-1.

4. Local Operational Procedures.  See XVIII Airborne Corps SOP and Fort Bragg 95-1.

(e) IFR Minimums and Procedures.  Prior to departure from within, or prior to entering controlled airspace, a pilot must receive an air traffic clearance, if weather conditions are below VFR minimums.  Standard IFR separation is provided to all aircraft operating under IFR in controlled airspace.

            Fuel Requirements:  For IFR flight, the aircraft, at takeoff, must have enough fuel to reach the destination airport and alternate airport (if required) and have a planned fuel reserve of 30 minutes cruise.

            IFR Flight:  Destination weather must be forecast to be equal to or greater than the published weather planning minimum for the approach procedure to be flown at ETA through one hour after ETA.  When there are intermittent weather conditions, predominant weather will apply.  Aviatros flying helicopters may reduce destination and alternate Category A visibility minimums by 50 percent, but not less than 1/4 mile or metric equivalent.  Reduction of visibility for approaches labeled “COPTER ONLY” is not authorized.  Category II approach procedures may not be used in destination or alternate weather planning.

            Area Forecast:  If there is no weather reporting service, the aviator may use the area forecast.

            Weather Briefing:  Local commanders will establish policies specifying when DD Form 175-1 is required to be filed with DD Form 175.  Weather information for DD Form 175-1 will be obtained from a military weather facility.  If a military forecaster is not available, the pilot-in-command will obtain a weather forecast per DOD FLIP.

For all IFR and VFR cross country flights, the weather forecast will be void one hour and 30 minutes from the time the forecast was received provided the aircraft has not departed.  Weather forecasts may be extended after coordination with a weather facility.  The crew should update weather briefing information on stopover flights.

            Approval Authority:  The pilot-in-command has approval authority for aircraft under his or her control when performing missions directed by the commander.

            Departure Procedures:  The aviator flying the aircraft on takeoff who has logged 50 hours, or more, of actual weather time as pilot-in-command has no Army takeoff minimums.

The aviator flying the aircraft on takeoff who has not logged 50 hours of actual weather time has the following takeoff minimums:  (helicopters only)

                                    Ceiling 100’ and visibility either ¼ mile, RVR 1200’ or metric equivalent.

All aviators will comply with published nonstandard IFR takeoff minimums and departure procedures in flight information publications.

            Holding:  An aviator may request ATC clearance to hold at any time if fuel and alternate requirements can be met.

            Approach:  Acceptance of charted visual approach clearance is not mandatory.

When an instrument approach is necessary, an approved procedure will be flown.  Approved procedures are published by the military services and FAA, in DOD and NOS FLIP.

When published landing visibility minimums require conversion between RVR and miles or metric equivalent, the conversion table in DOD FLIP will be used.  RVR is the controlling visibility factor when published and reported for a runway.  RVR, however, will not be used with a circling approach.

Dual VOR requirements specified on approach charts do not apply to army aircraft.  Off-tuning from the approach NAVAID to identify an approach fix is authorized.  Dual VOR approach minimums apply.

                        An approach may be initiated regardless of ceiling or visibility.

Category II ILS approaches in IMC are authorized only when all provisions in AR 95-1 are met.  Descent on category II approaches is restricted to the highest DH published for the procedure selected.

Practice hooded approaches may be made to the decision height or minimum descent altitude when the aircraft has dual controls and a copilot is at one set of controls.  In all other cases, hooded approaches may not be made lower the 500’ AGL.

            Missed Approach:  The published missed approach procedure or other procedures as directed by ATC will be flown.  Additional approaches may be flown provided fuel, including reserve, is adequate.  An ATC clearance must be requested and approved before proceeding to another airfield.  A change of flight plan will be made per FLIP if time permits.

            Landing:  An aircraft will not be flown below the published MDA or an approach continued below the DH unless the following exists:

a.      The approach threshold of the runway, or the approach lights or other markings identifiable with the approach end of the runway or landing area, must be clearly visible to the pilot.

b.      The aircraft must be in a position from which a safe approach to the runway or landing area can be made.

Closing Flight Plans:  When the flight terminates, the PC will ensure the flight plan is closed as shown in DOD FLIP.

Alternate Requirements:

Alternate Airfield Planning:  An alternate airfield is required when filing IFR to a destination under any of the following conditions:

                        Radar is required to execute the approach procedure to be flown

                        The instrument approach navigational aids to be used are unmonitored.

                        The predominant weather at the destination is forecast at ETA through one hour after ETA to be less than

a.      Ceiling 400’ above weather planning minimum required for the approach to be flown.

b.      Visibility one mile (or metric equivalent) greater than the planning minimum required for the approach to be flown.

An alternate is not required if descent from enroute minimum altitude for IFR operation, approach, and landing can be made in VFR conditions.

                        Minimum Altitude for IFR Operations is defined as:

                                    If not flying on a published route or route segment

                                    In the case of operations over an area designated as mountainous area, an altitude of 2000’ above the highest obstacle within a horizontal distance of four nautical miles from the course to be flown; or, in any case, an altitude of 1000’ above the highest obstacle within a horizontal distance of four nautical miles from the course to be flown.

                                    However, if both a MEA and MOCA are prescribed for a particular route or route segment, a person may operate an aircraft below MEA down to, but not below, the MOCA, when within 22 nautical miles of the VOR concerned (based on the pilot’s reasonable estimate of that distance).

                        Alternate Airfield Selection:  An airfield may be selected as an alternate when the worst weather condition for that airfield is forecast at ETA through one hour after ETA to be equal to or greater than

                                    Ceiling 400’ above the weather planning minimum required for the approach to be flown and visibility one mile (or metric equivalent) greater than the weather planning minimum required for the approach to be flown; or

                                    VFR minimums and descent from enroute minimum altitude for IFR operation can be made in VFR conditions.

                                    An airfield will not be selected as an alternate except per above (VFR Descent):

a.      If the approach procedure to be used at the alternate is shown not authorized (NA) in FLIP.

b.      If radar is required for the approach procedure to be used at the alternate.

c.      If the instrument approach navigational aids to be used are unmonitored.

d.      If Class B, C, D, or E surface area airspace does not exist or is not in effect at the airport to be used.

e.      If the global positioning system (GPS) is required for the approach.

(f) Aviation-Life Support Equipment.

AR 95-3 states that PICs will ensure that Life Support Equipment commensurate with the mission and the operational environment is available on the aircraft and that crewmembers and passengers are briefed on its location and use. 95-3 further states that safety equipment (breakout knives, fire axes, etc.) will be installed per the requirements of the appropriate operator's manual. Each crewmember will wear a survival radio. Each crewmember will wear a survival vest with components. Please be prepared to discuss the contents, location, and use of components of your survival vest. All persons aboard Army aircraft flown beyond gliding distance to land will wear life preservers. The following U.S. Army approved clothing and equipment will be worn by all crewmembers when performing crew duties. * Leather boots * Flight helmet * Flight suit * Flight gloves *Cotton, wool, or Nomex underwear (No synthetics)

AR 670-1 states, in part, "All military personnel will wear ID tags when riding in military aircraft."

(g) Weight and Balance Requirements.

AR 95-1 states that the PIC will ensure that the aircraft is within weight and cg limits for the duration of the flight, that computations on the 365-4 are accurate, and that sufficient 365-4s are aboard the aircraft to verify weight and cg will remain within limits. A single form for specific loading conditions may be used, or several forms covering the range of loading conditions may substitute. In the latter case, the actual loading must clearly be within the extremes of loading used on the forms. AR 95-3 states all Form 365-4s will be checked for accuracy every 90 days. Small differences may exist between the 365-4 and DD Form 365-3 (Basic Weight and Balance Record), provided the differences do not exceed +/- 3/10 of 1% of basic weight or .3 inches cg. Temporary equipment changes may be noted on either the -13 or -14 as "not entered on DD Form 365-3". These changes will be accounted for on the 365-4, either by using the corrections section, or, as stated above, by verifying new weight and cg fall within range of previously computed loading configurations. These logbook entries should state the weight and arm of the equipment installed or removed and may not be carried for longer than 90 days.

(h) Flight Plan Preparation and Filing.  Check your local procedures (Corps SOP and local AR 95-1).

(i) Flight Restrictions Due to Exogenous Factors.   Reference AR 40-8.

Flight safety requires that medical treatment of all aircrew members be under the supervision of a flight surgeon who is aware of the exogenous factors affecting flying and the appropriate preventive measures. Aircrew members will inform their flight surgeon when they have participated in-activities or received treatment following which flying restrictions may be appropriate. Factors to consider and appropriate medical restrictions to flying activities are:

1. Administration of Drugs. All drugs and medications will be dispensed by or with the knowledge of a flight surgeon. Individuals receiving the following drugs or types of drugs will be restricted from flying duties as indicated:

(aa) Alcohol - 12 hours after last drink consumed and until no residual effects remain.

(bb) Antihistamines or barbiturates - for the period taken and for 24 after discontinued or after any lingering effects, whichever is longer.

(cc) Mood ameliorating, tranquilizing, or ataraxics - for the period they are used and for 4 weeks after the drug has been discontinued.

(dd) Immunizations - minimum of 12 hours following all immunizations except smallpox and for the duration of any systemic or severe local reaction.

2. Blood Donations. Aircrew members will not be regular blood donors. Following donation of 200cc or more, aircrew members will be restricted from flying for 72 hours.

3. Diving. Aircrew members will not fly within 24 hours following SCUBA diving.

4. Tobacco Smoking. See Aeromedical factors, below.

5. Contact Lenses. Aircrew members will not wear contact lenses at any time.

(j) Range Operations and Safety.  See XVIII Airborne Corps and Fort Bragg Aviation Standard Operating Procedures.

(k) Inadvertent IMC Procedures and Vertical Helicopter Instrument Recovery Procedures.  The following procedures are not routine, standard operating procedures, but are to be executed after exhausting all efforts to maintain visual meteorological conditions (VMC) to include landing as soon as possible.  If IMC is inadvertently encountered, the pilot will implement the recovery procedures.  A turn away from IMC should be made before inadvertent entry.  Upon encountering IMC, the most important consideration is aircraft control.  The following procedures will be followed:

            Atitude Indicator – level aircraft.

            Heading Indicator – maintain constant heading.

            Torque Meter – adjust to climb power.

            Airspeed – establish climb airspeed.

            Climb to appropriate altitude or as assigned by ATC.  Initiate procedures only after transition to the instruments is complete, aircraft is under adequate control, and climb is established.  Turn only to avoid known obstacles.

            Immediate action will then be:

                        Set transponder to Code 7700 and contact Approach Control (or controlling agency) on appropriate frequency or 121.5/243.0.

Also be completely familiar with your local Aviation Standard Operating Procedures.

(l) *Test Flight Weather Requirements. See XVIII Airborne Corps and Fort Bragg Aviation Standard Operating Procedures.

(m) *Local Airspace Usage (test flight). See XVIII Airborne Corps and Fort Bragg Aviation Standard Operating Procedures.

(n) *Publications Required in the Aircraft.  Reference DA Pam 738-751 and AR 95-1, the publications and forms below will be located in the aircraft during its operation:

            Operator’s Checklist

            Operator’s Manual (-10) including changes and related SOF TBs

            Current DD Form 365-4 (Weight and Balance Clearance Form)

            Equipment Logbook Assembly consisting of the following items:

                        DA Form 2408 (Equipment Logbook Assembly (Records))

                        DA Form 2408-31 (Aircraft Identification Card)

                        DA Form 2408-4-3/2408-4-3-E (Weapon Sighting Data (AH-64A))

                        DA Form 2408-12 (Army Aviator’s Flight Record)

                        DA Form 2408-13 (Aircraft Status Information Record)

                        DA Form 2408-13-1 (Aircraft Inspection and Maintenance Record)

                        DA Form 2408-13-2 (Related Maintenance Action Record)

                        DA Form 2408-14 (Uncorrected Fault Record)

                        DA Form 2408-18 (Equipment Inspection List)

            Current Editions of Flight Publications required for the mission

            Other items required by local regulations

(o) *Maintenance Operational Check Requirements.

(p) *Maintenance Test Flight Requirements.

(q) *Maintenance Test Flight Forms and Records.

(2) OPERATING LIMITATIONS AND RESTRICTIONS (TM 1-1520-237-10 or TM 1-1520-253-10)

(a) Wind Limitations 

(b) Rotor Limitations 

(c) Power Limitations 

(d) Engine Limitations 

(e) Weather Limitations  See AR 95-1 and local regulations

(f) Pressure Limitations 

(g) Airspeed Limitations 

(h) Temperature Limitations 

(i) Flight Envelope Limitations 

(j) Performance Chart Interpretation  See Chapter 7 of the Operator’s Manual

(k) Weight and Balance Requirements 

(l) Aircraft System Limitations 

(m) Weapon System Limitations  See Operator’s Manual and FM 1-140

(n) Laser Limitations 

(o) FLIR and NVD Limitations 

(3) AIRCRAFT EMERGENCY PROCEDURES AND MALFUNCTIONS ( TM 1-1520-237-10 or TM 1-1520-253-10)           

(a) Emergency Terms and Their Definitions 

(b) Emergency Exits and Equipment 

(c) Engine Malfunction and Restart Procedures 

(d) Rotor, Transmission, and Drive Systems  

(e) Tail Rotor Malfunctions 

(f) Chip Detectors 

(g) Fires and Hot Starts 

(h) Smoke and Fume Elimination 

(i) Hydraulic System Malfunction 

(j) Fuel System Malfunction 

(k) Electrical System Malfunctions 

(l) Caution and Warning Light Emergency Procedures 

(m) Landing and Ditching Procedures 

(n) Auxiliary System Malfunctions 

(o) Flight Control or Main Rotor Malfunctions 

(p) Fault Detection and Location System Procedures 

(q) Mission Avionics Malfunctions 

(r) Weapon System Malfunctions

(s) Night Vision System Malfunctions 

(t) IHADSS Malfunctions 

(4) AEROMEDICAL FACTORS (FM 1-301 and TC 1-204)

PowerPoint presentations from the US Army Aviation School of Medicine:

                    Altitude Physiology                                        Aviation Protective Equipment Orientation

                    Aviation Toxicology                                        Gravitational Forces

                    Night Vision Orientation                                 Noise in Army Aviation

                    Spatial Disorientation                                     Stress and Fatigue

                    Noise in Army Aviation                                   Link to Aviation School of Medicine Student Handouts (Internet connection required)

 

(a) Hypoxia. In simple terms, hypoxia is the result of insufficient oxygen in the body. There is a tendency to associate hypoxia only with flight at higher altitudes. There are, however, many other conditions or situations which can and do interfere with the blood's ability to carry oxygen. Alcohol, many drugs, and heavy smoking can either diminish the blood's ability to absorb oxygen or diminish the ability of the body to. tolerate hypoxia. There are four major classes of hypoxia: hypoxic, hypemic, stagnant, and histotoxic. Classification is made according to the cause of lack of oxygen.

1. Hypoxic Hypoxia. Hypoxic hypoxia occurs when there is not enough 02 in the air breathed or when conditions prevent the diffusion of 02 from the lungs to the bloodstream. This type of hypoxia is the one likely to be encountered at altitude. It is due to the reduction of the partial pressure of 02 occurring with altitude.

2. Hypemic Hypoxia. Hypemic (or anemic) hypoxia is caused by a reduction in the capacity of the blood to carry a sufficient amount of 02. Anemia and blood loss are the most common causes of this hypoxia. Carbon monoxide nitrates, sulfa drugs, and so on, can also cause this hypoxia by forming compounds with the blood hemoglobin. The amount of hemoglobin available to combine with 02 is thus reduced.-

3. Stagnant Hypoxia. This type of hypoxia, like hypemic hypoxia, is due to a malfunction of the circulatory system, but differs in certain respects. While the 02 carrying capacity of the blood is adequate, there is an inadequate circulation of the blood. Such conditions as heart failure, arterial spasm, occlusion of a blood vessel, and the venous pooling encountered during high G maneuvers would predispose the individual to stagnant hypoxia.

4. Histotoxic Hypoxia. This type of hypoxia results when the use of 02 by body tissue is interfered with. Alcohol, narcotics, and certain poisons, such as cyanide, interfere with the capacity of the cells to make use of the 02 available to them even though the supply of 02 is normal in all respects.

Stages of Hypoxia. There are four stages of hypoxia; indifferent, compensatory, disturbance, and critical. The stages may vary according to altitude, stress loads, and individual tolerances.

1. Indifferent stage. The only consistent effect of mild hypoxia existing in this stage is the deterioration of night vision which becomes significant at about 4,000 ft. Pilots and crewmembers who fly above 4,000 ft. at night should be well aware that there is a significant loss of visual acuity.

2. Compensatory stage. The circulatory system and, to a lesser degree the respiratory system provide some defense against hypoxia at this stage. The pulse rate, the systolic blood pressure, the rate of circulation, and the cardiac output increase. Respiration increases in depth and sometimes in rate. At 12,000 to 15,000 feet, however, the effects of hypoxia on the nervous system become increasingly apparent; after 10-15 minutes, impaired efficiency is obvious. The individual may become drowsy and make frequent errors in judgment. He may also have difficulty with simple tasks requiring mental alertness or moderate muscular coordination. The most crucial thing about hypoxia at this stage is that it can be easily overlooked when performing other tasks.

3. Disturbance stage. In this stage, the physiological responses can no longer compensate for the oxygen deficiency. Occasionally, there are no subjective symptoms of hypoxia until the time of unconsciousness. More often, symptoms such as fatigue, sleepiness, dizziness, headache, breathlessness, and euphoria are reported. The objective symptoms are:

(aa) Senses. Peripheral vision and central vision are impaired and visual acuity is diminished. There is weakness and loss of muscular coordination. Touch and pain are diminished or lost. Hearing is one of the last senses to be lost.

(bb) Mental processes. Intellectual impairment is an early sign which often prevents the individual from recognizing his disability. Thinking is slow and calculation are unreliable. Short-term memory is poor and judgment and reaction time are also affected.

(cc) Personality traits. There may be a release of basic personality traits and emotions as with alcoholic intoxication. This sometimes results in euphoria, aggressiveness, overconfidence or depression.

(dd) Psychomotor functions. Muscular coordination is decreased and delicate or fine muscular movements may be impossible. Stammering, illegible handwriting, and poor coordination are typical of this stage of hypoxia impairment.

(ee) Cyanosis. The skin becomes bluish in color. This is due to the failure of an oxygen molecule to attach to the hemoglobin molecule.

4. Critical stage. Within 3 to 5 minutes, judgment and coordination deteriorate and subsequent mental confusion, dizziness, incapacitation, and unconsciousness result.* Here, we deviate slightly from the outline of the ATM. Because fatigue is a result of stress, we'll first talk about stress.

(b) Carbon Monoxide - effects are subtle and deadly. It is colorless, odorless, and slightly lighter than air. The affinity of human hemoglobin for carbon monoxide is from 200 to 300 times its affinity for oxygen. Sources are many, i.e., exhaust gasses, hydraulic fluid vapors, engine lubricants, etc.

1. Symptoms of Carbon Monoxide Poisoning include: headache, weakness, nervousness, muscular twitching, joint pain, tremors, muscular cramps, impairment of speech and hearing, and hoarseness.

2. Treatment includes: artificial respiration, administration of 100% oxygen, and application of warmth.

(c) Self-Imposed Stresses. (NOTE:  For the purposes of this study guide, stress is discussed at length…Self-Imposed Stresses are contained within these notes…)  Stress results from a perceived imbalance between a demand and the ability to meet that demand. Stress affects individuals differently and causes them to vary daily in states of fitness. Everyone, however, has a breaking point. Because of this fact, it is important for aircrew members to recognize some of the causes of stress, as well as possible symptoms and alleviation. While stress can come from many sources, it can generally be considered to be either acute or chronic.

1. Acute Stress. Acute stress has the most immediate impact. It is-usually very intense in nature and occurs within a relatively short period of time. Immediate fear of failure, fear of physical harm, physical discomfort, or work load can contribute to acute stress.

2. Chronic Stress. Chronic stress differs substantially from acute stress. It is not as intense in nature and can last months or years. Duty assignments, physiological environment and illness contribute to chronic stress. Over a period of time, it can become more debilitating than acute stress, and can lead to physical illnesses such as ulcers and migraine headaches.

(a) Stress Sources. Two types of stress associated with aviation are aviation-related stress and self-imposed stress. Both types are cumulative and can lead to debilitating fatigue.

1. Aviation-Related Stress. Although aircrew members may have no control over some aviation-related stresses, they need to know the sources and understand the effects of this type of stress. Some of these sources are:

(aa) Altitude. Stress caused by altitude changes is most evident at altitudes below 5000 feet, where the greatest atmospheric changes occur. Also, even common colds can cause ear and sinus problems on descent from altitude.

(bb) Speed. Speed is stressful because it requires increased alertness and optimal response level.

(cc) Hot or Cold Environment. Extreme heat or cold causes temperature stress.

(dd) Aircraft Design. Lighting, cockpit design, and cabin environment can all divert attention and contribute to stress. Such factors as instrument location, accessibility of switches and controls, seat comfort, heating and ventilating systems, lighting, visibility, and noise levels all directly affect pilot performance.

(ee) Aircraft Characteristics. The inherent instability of helicopters require constant pilot attention and contributes to both acute and chronic stress.

(ff) Weather. Both IFR and VFR flights in poor weather bring a perceived need for greater vigilance and accuracy in reading, following, and monitoring flight instruments and navigation publications. Stress of night flight is similar to stress of flying in poor weather. Decreased awareness of color, visual acuity, and depth perception all increase aviation stress levels.

3. Self-Imposed Stress. As opposed to aviation-related stress, over which the aviator has little or no control, they can exert significant control over self-imposed stress. These stresses can be remembered by the acronym "DEATH", which stands for Drugs, Exhaustion, Alcohol, Tobacco, and Hypoglycemia.

(a) Drugs. Many drugs are incompatible with safe flying and must never be used without medical supervision. Most drugs are designed to either cure a medical problem or alleviate symptoms. In either case, they almost always have side effects, both predictable and unpredictable, which include allergic reactions and individual idiosyncrasies. Unpredictable synergistic effects can also arise either by combining drugs or taking even prescribed drugs under stressful situations. SELF MEDICATION SHOULD NEVER BE ATTEMPTED BY AIR CREWMEMBERS.

(b) Exhaustion. Lack of rest or sleep, whether due to environment, work requirements, emotional stress, or changes in time zone adversely affect performance. Sleeping difficulties should be discussed with the flight surgeon. (Note: See Fatigue below, paragraph (c)).

(c) Alcohol. Alcohol acts as a depressant. Even small amounts have detrimental effects on judgment, perception, reaction time, and coordination. Alcohol reduces the brain cells' ability to use oxygen and increases the physiological altitude. Taking cold showers, drinking coffee, or breathing loot oxygen does not speed up the body's metabolism of alcohol. After consuming alcohol, an aviator should wait AT LEAST 12 hours before flying. The period should be extended beyond 12 hours whenever side effects exist.

(d) Tobacco. One by-product of smoking is carbon monoxide. Carbon monoxide attaches to hemoglobin molecules 200-300 times more readily than does oxygen. Thus, the presence of carbon monoxide robs the body of oxygen, causing hypoxia (see paragraph (e), below). The average smoker's physiological altitude is 50001 when he is at sea level (Because of less oxygen available, the average nonsmoker loses some night vision beginning at 40001). Thus, smoking reduces night vision capabilities. Apart from this, the chronic irritation of the lining of the nose and lungs increases the likelihood of infection and illness. To aviators, this affects the ability to cope with effects of pressure changes in the ears and sinuses.

(e) Hypoglycemia. Because of mission requirements, aviation crew members often disrupt their regular eating habits and skip meals. This can lead to the problem of hypoglycemia. Hypoglycemia is a low blood sugar level resulting in a rundown feeling. If the aviator tries an immediate "fix" such as a candy bar, hyperglycemia usually results. Hyperglycemia is an unusually high level of blood sugar. The body's reaction is to secrete insulin, which decreases the blood sugar level, compounding the original problem. The best solution is to-maintain a nutritious, well balanced diet and avoid high sugar "fixes".

4.  Fatigue. Fatigue is caused by stress. It can encompass not only problems with motor skills but also those associated with mental processes. As with stress, fatigue can be thought of as acute or chronic.

a. Acute Fatigue. End-of-the-day tiredness that results in loss of both coordination and awareness of errors. Acute fatigue is characterized by inattention, distractibility, errors in timing, neglect of secondary tasks, and need for greater stimuli.

b. Chronic Fatigue. Far more serious than acute fatigue, chronic fatigue occurs over a longer period of time. Chronic fatigue is often characterized by insomnia, depression, weight loss, irritability, poor judgment, loss of appetite, and slowed reaction times.

aa.  Reduction of Fatigue. Physical and mental well-being are essential to carrying out complex, skilled tasks. Proper stress management and fatigue reduction enable the aviator to successfully complete his mission. Some management and reduction techniques are:

1. Good general physical fitness

2. Limitation of self-imposed stress

3. Good living conditions with adequate food and rest

4. Improved working conditions

5. Adequate recreation

6. Local crew endurance policies

7. Consult with a flight surgeon if problems exist

Stress and Fatigue Class from the US Army Aviation School of Medicine

(d) Middle Ear Discomfort or Pain caused by inability to equalize middle ear and ambient pressure. Usually associated with rapid descents from altitude. This condition is aggravated by upper respiratory infections such as colds, etc., which cause the Eustachian tubes to become partially blocked and inflamed, blocking the passage of air into the middle ear. As this occurs, the eardrum becomes distended inward causing pain or discomfort. The only relief for this condition is to equalize the pressure by returning to altitude, or by performing the valsalva maneuver. Don't fly with acute upper respiratory infections and avoid rapid descents from altitude. Also take care passengers are comfortable with changes in pressure and are aware of the valsalva maneuver.

(e) Spatial Disorientation - exists when an individual does not correctly perceive his position, attitude, and motion relative to the center of the earth. Sensory illusions may lead to spatial disorientation in flight. When this occurs, the pilot is unable to see, believe, process, or rely on information provided by his flight instruments and relies instead on false information received by his bodily senses. Prevention of spatial disorientation includes never flying without visual reference points, either the horizon or artificial horizon provided by instruments. Trust your instruments. Never stare at lights. Establish a good degree of night visual adaptation prior to takeoff on any night instrument or VFR flight. Avoid fatigue, smoking, hypoglycemia, hypoxia and anxiety.

                    Spatial Disorientation Class from the US Army Aviation School of Medicine

(f) Eye Anatomy and Physiology - The eye is similar to a camera. The cornea, lens, and iris gather and control the amount of light allowed to enter the eye. The image is then focused on the retina. The visual receptive apparatus (retina) has two types of cells, cones and rods. Vision is possible because of chemical reactions within these cells.

1. Cones. Cone cells are used primarily for day or high-intensity light vision. The concentration of cones in the central retina (fovea centralism permits high visual acuity in high illumination. The chemical iodopsin is always present in the cone cells. Regardless of the ambient light condition, this chemical is readily available so that the cones can immediately respond to visual stimulation.

2. Rods. The rods are used for night or low-intensity light vision. The peripheral retina is almost exclusively associated with rods. Peripheral vision is less precise than central vision because rods perceive only shades of gray and vague form or shape. Rhodopsin, commonly referred to as visual purple, is the photochemical found in rods. As the light level decreases, the amount of rhodopsin in the rods builds and the rods become more sensitive. When illumination decreases to about the level of full moonlight, the rods take over from the cones. The highest light sensitivity is usually achieved after 30 to 45 minutes in a dark environment. The rod cells, nominally 1000 times more sensitive to light than cones, may become up to 10,000 times more sensitive when fully dark adapted.

(5) AERODYNAMICS (FM 1-203)

(a) Relative Wind: is the apparent motion of air in relation to a body, whether the air moves about the body or the body moves through the air. The rotation of rotor blades as they turn about the mast produces rotational relative wind. Rotational relative wind flows opposite the path of the rotor blades, parallel to the plane of rotation. Velocity is highest at the blade tips, decreasing to zero at the mast. induced flow is the component of air flowing vertically through the rotor system. It results from the production of lift. The resultant relative wind (at a hover) is the rotational relative wind as modified by the induced flow.

(b) Total aerodynamic Force: As air flows around an airfoil, a pressure differential develops between the upper and lower surfaces. The differential, combined with the resistance of the air, creates a force on the airfoil. This force, known as total aerodynamic force, acts through the center of pressure of the airfoil and includes airfoil lift, induced drag, and parasite or profile drag.

(c) Airflow During a Hover: At a hover, blade-tip vortices reduce the effectiveness of the outer blade portions. A helicopter hovering out-of-ground effect also creates high velocity induced flow, which reaches its maximum approximately one rotor disk below the plane of rotation. The result is high blade pitch angles and high power settings during OGE hovering. Increased blade efficiency during in-ground-effect hovering is due to two phenomena: reduction of induced flow and, as the flow pattern is deflected outward, reduction of rotor-tip vortices. Rotor efficiency is increased by ground effect up to a height of about one rotor diameter. Maximum ground effect occurs when over smooth, flat surfaces. See diagrams following text.

Out of Ground Effect In Ground Effect

(d) Translating Tendency: During hovering flight, thrust of the tail rotor is used to compensate for main rotor torque effects and maintain heading control. The horizontal thrust of the tail rotor tends to cause the helicopter to drift laterally to the right. The aviator may prevent this lateral drift by tilting the main rotor disk in the opposite direction. This lateral tilt results in a main rotor force opposite the tail rotor thrust. Helicopter design usually includes at least one feature that helps compensate for translating tendency. This may include flight control rigging that tilts the rotor when the cyclic is centered or increases tilt as collective is increased, or the main transmission may be mounted so that the mast is tilted slightly.

(e) Transverse Flow  As the forward velocity of the helicopter increases, another phenomenon of differential airflow in the rotor system occurs.  While dissymmetry of lift involves the advancing and retreating sides of the rotor disk, transverse flow effect involves the front and rear halves of the rotor disk.  Its most noticeable effects take place between 10 and 20 knots depending on aircraft size, blade area, and RPM of the rotor system.  Because of coning and the forward tilt of the rotor system, there is a differential airflow across the front and rear halves of the rotor disk.  This is the transverse flow effect.  The pilot can recognize the transverse flow effect because of increased vibrations at airspeeds just below effective translational lift on takeoff and after passing through effective translational lift during landing.  These vibrations take place because the greatest lift differential between the fore and aft portions of the rotor system occurs at those airspeeds.  The vibrations are caused by increased induced drag on the blades as they pass over the tail of the helicopter.

(f) Dissymmetry of Lift is a transitory difference in lift produced by the advancing and retreating halves of the rotor system. Because the directional movement of the helicopter is added to the rotational velocities on the advancing half of the rotor disk and subtracted from rotational velocities on the retreating half, a speed differential exists and several distinct 'no-lift, airflow regions are created on the retreating side. Near the hub, air actually flows backwards over the blade, creating the 'reverse flow' area. At some point along the span of the blade, rotational velocities exceed translational velocities, and airflow moves from leading edge to trailing edge. Induced flow, however, causes the relative wind to strike the blade from above, creating successive areas of negative stall and negative lift (lift vectors actually point down). As we move span-wise out along the blade, flapping moments and increasing rotational velocities finally succeed in creating a positive lift area, but near the tip of the blade a positive stall area is created and grows toward the blade root as aircraft velocities increase. Thus an ever-shrinking area on the retreating blade is required to produce the same amount of lift as the entire advancing blade. A brief look at the lift formula groan) reveals what a daunting task this is. The formula (L = C L ½ P S V2) shows that lift increases exponentially as speed increases. The factors of air density and blade area (P and S) are the same for both halves of the rotor disk, leaving only the coefficient of lift (CL) to compensate for the speed differential. The coefficient of lift is determined by airfoil shape and angle of attack; thus increased angles of attack allow the retreating blade to produce equal lift (but also lead to retreating blade stall). Blade flapping alone (by increasing angle of attack on the retreating blade and decreasing it on the advancing blade) compensates for dissymmetry of lift, but would cause the rotor disk to tilt aft.

(g) Retreating Blade Stall: As helicopter speeds increase, less and less of the span of the retreating blade actually produces positive lift. Increased flapping angles are required to compensate, but lead to higher angles of attack and, ultimately, retreating blade stall. Stalls begin at the tip of the retreating blade (where flapping moments are greatest) and spread inward as helicopter speeds increase. Along with high forward speeds,, high gross weights, low rotor RPM, high density altitude, steep or abrupt turns, and turbulent air all contribute to the onset of retreating blade stall. In single-rotor helicopters, the first sign of impending stall is generally a noticeable vibration, which may be followed by a left roll and pitch up (this may not be significant in pendular semi-rigid systems) and, finally, loss of control. In tandem rotor helicopters, the pitch up is insignificant. Blade stall is indicated by increased vibration. Blade stall will often occur on the aft rotor first because it operates in the wake of the forward rotor. If stall is suspected, the pilot should reduce power, reduce airspeed, reduce maneuvering, increase rotor RPM (within limits), and check pedal trim.

(h) Compressibility  Reference 1-203, Fundamentals of Flight.

(i) Dynamic Rollover: A helicopter is susceptible to a lateral rolling tendency called dynamic rollover. It can occur on level ground but is more likely to occur and is more hazardous during slope or crosswind takeoff or landing maneuvers. When a helicopter lands on a slope, the mast is perpendicular to the inclined surface but the plane of the rotor disk must parallel the true horizon (or even tilt slightly upslope). Normally, rotor control is limited by cyclic control stops, static stops, mast bumping, or other mechanical limits. These limits are reached much sooner in down-slope wind conditions. When the helicopter hangs one side low and is landing with the low side upslope, there is also less control travel. Each helicopter has a critical rollover angle beyond which recovery is impossible. If the critical angle is exceeded, the helicopter will rollover regardless of cyclic input. The rate of roll is also critical. As the rolling rate increases, the critical angle is reduced. The critical angle is constantly changing based on such variables as which skid is on the ground, crosswind component, lateral CG offsets, and left pedal inputs. With one skid on the ground, lateral cyclic control is sluggish. The skid may become a pivot point for a variety of reasons, including being caught on protruding objects or in a soft surface, or through improper handling techniques which can 'force' a skid into the ground. A smooth, moderate collective pitch change may be the most effective way to stop a rolling motion. Sudden reduction of collective could start a roll about the downhill skid once it makes contact, and sudden increase will increase the rolling moment should the skid remain fixed; and, even if it breaks free, could result in a pendulum action of the fuselage which could become uncontrollable.

(j) Settling with-Power: Also referred to as the vortex ring state, this is a condition in which the helicopter settles in its own downwash. Conditions conducive to settling with power are a vertical or near-vertical descent of at least 300 feet per minute and low forward speed. The rotor system must also be using 20 percent or more of available power with insufficient power available to retard the sink rate. These conditions can occur during downwind approaches, NOE flight, formation takeoffs or approaches,, steep approaches, masking and unmasking, and OGE hovering. Generally, settling with power can be avoided by descending on flight paths shallower than approximately 30 degrees (at any airspeed). If encountered,, recovery can be made by increasing translational velocities (forward, lateral, or rearward airspeed) and/or decreasing collective pitch. In tandem rotors, recovery should be attempted using lateral cyclic inputs (fore and aft inputs could aggravate the situation).

Induced-flow velocity during hovering flight

Induced-flow velocity before vortex ring state

Vortex Ring State

(k) Gyroscopic precession: a phenomenon in rotating systems that makes all forces react with a movement 90 degrees from the point of force in the direction of rotation.

(l) Airflow in Forward Flight: Airflow across the rotor system in forward flight varies somewhat from airflow at a hover. Relative wind now becomes the result of rotational relative wind, induced flow, and translational flight. Relative airflow direction and speed are constantly changing as the blades rotate through the moving air mass. As the rotor system moves from a hover into forward flight, turbulence and vortices are left behind, and main and tail rotors both become more efficient. Improved rotor efficiency resulting from directional. flight is called translational lift. At about 16 to 24 knots, the rotor system completely outruns the recirculation of vortices, allowing the entire rotor system to operate in relatively undisturbed air. This point is referred to as effective translational lift (ETL). Directional flight also results in the rotor system having an advancing and retreating side, resulting in dissymmetry of lift (See next paragraph). Below ETL, pronounced blowback results from this dissymmetry and, coupled with gyroscopic precession ' causes the rotor system to tilt back. Pilots must overcome this blowback by moving the cyclic forward to maintain the desired disk attitude. Transverse flow also occurs below ETL. Transverse flow is a condition of increased drag and decreased lift in the aft portion of the rotor disk caused by the air having a greater induced flow in the aft portion. It is characterized by the disk tilting to the right (again, because of the lag of gyroscopic precession). At higher speeds, dissymmetry of lift causes other problems and, ultimately, limits the maximum speed of the helicopter and effects controllability.

Cyclic feathering allows the pilot to keep the rotor disk tilted forward and, as it changes the angle of incidence on both the advancing and retreating sides, it also helps to compensate for dissymmetry of lift. (On 'delta-hinge' tail rotors, the angle between the trunnion journals and the pitch change links actually cause the blades to feather as they flap). Up to the point of retreating blade stall, flapping and feathering equalize the lift and there is no difference in total lift being produced (the "dissymmetry" being more in how the lift is produced). Thus the 'transitory' nature of dissymmetry of lift.

(6) ATTACK HELICOPTER TACTICAL AND MISSION OPERATIONS (FMs 1-112, 1-114, 1-116, 1-400, and 1-402; 1-201, and 1-204; and unit SOP)

Refer to Evaluation Guidelines in ATM for list of subjects to be covered. Your individual Commander's Task List identifies specific tasks for which you are responsible. Refer to Chapter 6 in ATM for task conditions, standards, and descriptions.

(a) Fighting the Battle (AH-64).

(b) Battlefield Environment.

(c) Mission Statement and Employment Methods.

(d) Combined-Arms Operations.

(e) Attack Planning and Terrain Analysis.

(f) Tactical Formations and Fire Control.

(g) Target Coordination and Laser Designation.

(h) Fire Support and Joint Air Attack Team Operations.

(i) Tactical Reports.

(j) Evasive Maneuvers.

(k) Terrain Flight Planning and Safety.

(l) Battle and Firing Position Selection.

(m) Downed Aircraft Procedures.

(n) Navigational Chart, Map, and Tactical Overlay Interpretation.

(o) Major U.S. or Allied Equipment and Major Threat Equipment Identification.

(p) *Aerial Observation.

(q) *Area, Route, and Zone Reconnaissance.

(r) *Call for and Adjustment of Indirect Fire.

(7)  MISSION AVIONICS OPERATION AND DEPLOYMENT (FM 1-112, TC 1-140, and TM 1-1520-237-10 or TM 1-1520-253-10).

(a) Doppler and HARS Operation. 

(b) IHADSS Operation and Boresight. 

(c) TADS Operation and Boresight. 

(d) Target Storing and Way Point updates (FCC).

(e) TADS Target Tracking: IAT, Manual, and LMC.

(f) TADS Slaving and Cueing Operations.

(g) Target Acquisition:  LST, TADS, and IHADSS.

(h) HAD and AND Operations and Messages.

(i) Data Entry Keyboard Operations.

(j) Weapons Symbology.

(k) Aircraft Survivability Equipment. 

(l) Degraded System Operations.

(8) WEAPON SYSTEM OPERATION AND DEPLOYMENT (FM 1-112, FM 1-140, and ( TM 1-1520-237-10 or TM 1-1520-253-10).

(a) Point Target Weapon System:  LOBL. 

(b) Point Target Weapon System:  LOAL. 

(c) Area Weapon System. 

(d) Aerial Rocket Control System. 

(e) Combined Weapons Engagement Characteristics.

(f) Weapons Initialization, Arming, and Safety.

(g) Hellfire Missile Characteristics. 

(h) 30-Millimeter Ammunition Characteristics. 

(i) Hydra 70 Rocket Characteristics. 

(j) Ballistics. 

(k) Laser Operations (Range/Designator).

(9) NIGHT MISSION OPERATION AND DEPLOYMENT (FM 1-140, TC 1-204 and TM 1-1520-237-10 or TM 1-1520-253-10)

(a) Unaided Night Flight.  The design of some Army aircraft will degrade your ability to see outside the cockpit. To minimize the loss of night vision because of aircraft shortcomings, you must properly prepare the aircraft for night flight. Windscreens can reduce your ability to see outside the aircraft. To minimize the effect of windscreens on night vision, they must be kept clean. Remove dirt, grease, bugs, and scratches from the windscreen before each night flight. Aircraft instruments are easier to read under high levels of instrument illumination. However, the level of light needed for optimum reading interferes with maximum dark adaptation needed for seeing dim objects outside the aircraft. Interior lights also interfere with dark adaptation. They reflect off the windscreen, reduce outside visibility, and are subject to detection by the enemy.

To-minimize these effects, turn off all nonessential lights and keep the intensity of essential lights to the lowest usable level. In formation, all aircraft other than trail will have anti-collision lights out. Whenever possible, preflight should be accomplished in daylight. If the preflight must be performed at night, use a flashlight with an unfiltered lens. If they don't interfere with mission or safety considerations, landing lights should be pre-positioned. Increased scanning during hover and hover power checks will help reduce spatial disorientation. For takeoff, if sufficient illumination does not exist to view obstacles, an 'altitude-over-airspeed' type takeoff should be accomplished. Crewmembers not on the controls should make all internal checks. During approach, altitude, apparent ground speed and rate of closure may be difficult to estimate. To avoid abrupt changes in attitude, rate of descent should be slightly lower than during the day. After beginning the descent, airspeed may be reduced to 40-45 knots until apparent ground speed and rate of closure appear to be increasing. Rate of descent at touchdown should not exceed 300 fpm.

(b) Night Vision Limitations and Techniques.  As ambient light levels are reduced, the human eye has some serious problems which limits a crewmembers visual abilities. Dark adaptation is only the first step toward increasing the ability to see at night. Loss of color perception, acuity degradation and the night blind spot all make normal daylight viewing techniques unproductive. Thus techniques for night vision viewing must be used to overcome some of the problems associated with night vision. Because central vision is such an ingrained reflex, these techniques require considerable practice and concerted effort.

1. Off-Center Vision. Viewing an object using central vision during daylight poses no limitations; however, if the same technique is used at night, the object may not be seen. This is due to the night blind spot that exists during periods of low illumination . To compensate for this limitation, "off-center vision" must be used. This technique requires that an object be viewed by looking 10 degrees above, below, or to either side, rather than directly at the object. This allows the peripheral vision of the eyes to maintain visual contact with an object. Even using off-center vision, an object viewed for a period of time in excess of 2 to 3 seconds will tend to bleach out and become one solid tone. As a result, the object can no longer be seen. To overcome this limitation of night vision, the crew member must be aware of the phenomenon and avoid viewing an object longer than 2 to 3 seconds before shifting the eyes from one off-center point to another.

2. Scanning. Scanning techniques are important in identifying objects at night. To scan effectively, scan from right to left or left to right. Begin scanning at the greatest distance an object can be perceived (top) and move inward toward you position (bottom). Due to the inability of the light-sensitive elements of the retina to perceive images while in motion, use a stop-turn-stop-turn type motion. For each time you stop, scan an area approximately 30 degrees in width. This viewing angle will include an area approximately 250 meters wide at a distance of 500 meters. The duration of each stop is based on the degree of detail that is required, but should be no longer than 2 to 3 seconds. When moving from one viewing point to the next, overlap the previous field of view by 10 degrees.

3. Shapes or Silhouettes. Visual acuity will be significantly reduced at night. Because of this limitation, objects must be identified by their shape or silhouettes. The crew member's ability to recognize objects using this technique will be determined by his familiarity with the architectural design of the structures which are common to the area in which the mission is being flown. A silhouette of a building with a high roof and a steeple can be easily recognized as a church in America; however, churches in other parts of the world may have a low-pitched roof with no distinguishing features. Man-made features depicted on the map will also assist in recognition of silhouettes observed while in flight

(c) Visual Illusion.  As visual information decreases, the probability of spatial disorientation increases. Reduced visual references also create illusions that can induce spatial disorientation. There are several visual illusions which occur in the aviation environment.

1. Autokinesis. When a person stares at a static light in the dark, the light will appear to move. This phenomenon can be readily demonstrated by staring at a lighted cigarette in a dark room. Apparent movement will b4tgin after about 8 to 10 seconds. Although the cause is not known, it appears to be related to the loss of surrounding references which normally serve to stabilize your visual perceptions. This illusion can be eliminated or reduced by visual scanning, by increasing the number of lights, or by varying the intensity of the light. The most important of the three solutions is the visual scanning technique. You should not stare at a light or lights for longer than 10 seconds. An awareness of this illusion and how to cope with it are essential to ensure safe operations at night.

2. Ground Light Misinterpretation. A common occurrence is to mistake ground lights for stars. When this happens, the aviator unknowingly positions the aircraft in an unusual attitude to keep the lights above him. For example, some aviators have misinterpreted the lights along a seashore for the horizon and have maneuvered their aircraft dangerously close to the sea while under the impression of flying straight and level. Cross-check your instruments to avoid this problem.

3. Relative Motion. Relative motion is perceiving the motion of another aircraft as your own, or vice versa. If a pilot is at a stationary hover and another helicopter hovers by, as the other aircraft is picked up in the pilot's peripheral vision he may sense movement in the opposite direction. You may also experience this illusion during formation flying. You may interpret notion by the wingman or leader as movement of your aircraft. The only way you can correct for this illusion is to understand that such illusions do occur and that you should not react to them on the controls. Using proper scanning techniques can help prevent this illusion.

4. Reversible Perspective Illusion. An aircraft may appear to be retreating when it is in fact approaching your position. This illusion is often experienced when aircraft are on converging (or is it diverging) paths. Perceiving only the silhouette of an object compounds the problem, as a quartering-tail view closely resembles a quartering-head view. Watching position lights may help. If the intensity of the lights increases, the aircraft is approaching your position. If the lights become dim, the aircraft is retreating. The 'red-right-returning' rule may not help discern between converging and diverging traffic.

5. False Horizons. The illusion of false horizons is experienced when something other than the actual horizon is identified as being parallel to the horizon. For example, an aviator flying his aircraft between two cloud banks may position the aircraft in relation to the lower cloud bank because it seems to be parallel to the horizon. Cross-checking your instruments can help prevent this situation.

6. Altered Reference Planes. Approaching a line of mountains or clouds alters your plane of reference. You may feel that you need to climb even though your altitude is adequate. Additionally, when flying parallel to a line of clouds, you may have a tendency to tilt away from the clouds.

7. Height perception Illusion. Flying over desert, snow, or water causes an illusion of having more altitude than you actually have. This is because of a lack of visual reference. To overcome this problem, it may be necessary to drop an object (such as a chemical stick or flare) on the ground before landing. Flight when visibility is restricted by haze, smoke, or fog produces the same illusion of height perception.

8. Flicker Vertigo. A light flickering at a rate of 4 to 20 cycles per second can produce unpleasant and dangerous reactions. Such conditions as nausea, vomiting, vertigo, and on rare occasions, convulsions and unconsciousness may occur. Fatigue, frustration, and boredom tend to intensify these reactions. Most common cause for a helicopter crewmember would be any light source viewed through or reflecting off of the rotor system (A semi-rigid rotor system rotating at 354 RPM flickers at 11.8 cycles per second, 324 RPM at 10.8).

9. Fascination (Fixation). This illusion occurs when a pilot ignores orientation cues and fixes his attention elsewhere. This is especially dangerous at night. Aircraft ground closure rates are difficult to determine because of the reduction or absence of normal daylight peripheral movement. Increased scanning by the pilot will help prevent this illusion.

10. Structural Illusion. Structural illusions are caused by heat waves,, rain, snow, sleet, or other factors which obscure vision. For example, a straight line may appear to be curved when seen through a desert heat wave, or a wing tip light may appear to be double or move when viewed during a rain shower.

11. Size-Distance Illusion. This illusion results from viewing a source of light that is increasing or decreasing in brightness. You may interpret the light as approaching or retreating. For example, if the position lights on a nearby aircraft are switched from dim to bright, the aircraft may appear to jump toward you.

(d) Use of Internal and External Lights.

(e) Types of Vision.

1. Photopic - experienced when high levels of light exist. Cones concentrated in the fovea centralis are primarily responsible for vision in bright light. Because of the high light level, rhodopsin is bleached out and rod cells become less effective. Sharp image interpretation and color vision are characteristic of photopic vision.

2. Mesopic - experienced at dawn, dusk, and during periods of mid-light levels. Vision is achieved by a combination of both rods and cones. Visual acuity steadily decreases as the available light decreases. A reduction in color vision occurs as the light level decreases and the cones become less effective. Due to gradual loss of cone sensitivity, greater emphasis should be placed upon off-center vision and scanning for detection of objects.

3. Scotopic - Experienced when low-level light conditions exist. Cone cells become ineffective causing poor resolution of detail. Visual acuity decreases to 20/200 or less and total loss of color perception occurs. A central blind spot occurs due to the loss of cone sensitivity. Viewing objects must be accomplished by off-center viewing and scanning. The natural reflex of looking directly at an object must be reoriented by night vision training. A characteristic of this type of vision is that a din image may fade away if your eyes are held stationary for more than a few seconds.

4. Day vs. Night vision - differences between day and night visions involve color, detail, and retinal sensitivity. Color vision is lost under low illumination due to the rods' inability to distinguish distinct colors. Although rods may be as much as 10,000 times more sensitive to levels of light, they are insensitive to color. In order for color to be perceived at night, the intensity of the light must be above the threshold for cone vision. Because of the physiology and mechanics of the eye, perception of fine detail is impossible at night. Rods are less-densely concentrated than are cones, and the pupil is wide open, allowing greater dispersion of incoming light. Therefore, objects must be large or nearby to be seen at night. Identification of objects is based on perceiving shapes and outlines, not on distinguishing features. Also, because of the threshold of perception of the cone cells and the concentration of cones in the fovea centralis, a 5" to 100 night blind spot develops. objects viewed directly may not be detected. In order to perceive objects at night, you must use off-center vision and proper scanning techniques.

5. Visual Problems

(aa) Presbyopia is a condition in which loss of elasticity of the lens causes defective accommodation and inability to focus sharply for near vision. It usually becomes apparent at about age 40, and, due to the refractive qualities of light, may be compounded under conditions where red light is used for illumination.

(bb) Night Myopia - myopia is a condition in which images come to a focus in front of the retina resulting especially in defective vision of distant objects. Again because of the refractive qualities of light and the predominance of blue wavelengths at night, what might be a mild condition during the day may become unacceptably blurred at night. Both presbyopia and myopia can be compensated for using corrective glasses.

(cc) Astigmatism is an irregularity of the shape of the cornea that may cause an out-of-focus or distorted image.

(f) Distance Estimation and Depth Perception.  The cues to distance estimation and depth perception are easily recognizable using central vision during good illumination. As the light level decreases, the crew member's ability to accurately judge distance is degraded and his eyes are more subject to seeing illusions. A knowledge of the mechanisms and cues to distance estimation and depth perception will assist the aviator in making better judgment of distance at night. While flying at altitude, most of the distances outside the cockpit are so great that the binocular cues are of little,, if any, value. In addition, these cues operate on a more subconscious level than the monocular ones. Therefore, they are not as capable of being improved by study and training and will not be discussed here. Monocular cues used to aid in distance estimation and depth perception are geometric perspective, retinal image size, aerial perspective, and motion parallax (GRAM).

1. Geometric Perspective. An object may have many different apparent shapes, depending on the distance and angle from which it is being viewed. Types of geometric perspective are:

(aa) Linear Perspective. Parallel lines such as runway lights tend to converge as distance from the observer increases.

(bb) Apparent foreshortening. The true shape of an object or terrain feature may be indiscernible because of the angle of view. Thus a circular confined area appears elliptical when viewed from a distance and not directly overhead.

(cc) Vertical Position in the field. objects or terrain features which are farther away from the observer appear higher on the horizon than objects or terrain features that are closer to the observer. This does not work for elevated or airborne objects. A light on an elevated structure or on a low-level aircraft may be mistaken for more distant ground objects.

2. Retinal image size. The size of an image focused on the retina is perceived by the brain to be of a given size. Factors that are used to determine distance using the retina image are,.

(aa) Known size of objects. The nearer an object is to the observer, the larger is its retinal image. By experience, the brain learns to estimate the distance of familiar objects from the size of their retinal image. To use this cue, the observer must know the actual size of object and have prior visual experience with it. If no experience exists, an object's distance would be determined primarily by motion parallax.

(bb) Increasing and decreasing size of objects. If the retina image size of an object increases, it is approaching or moving nearer the observer. Whereas, if the size is constant, the object is at a fixed distance.

(cc) Terrestrial Associations. Comparison of an object, such as a confined area, with an object of known size, such as a tank, will help to determine the relative size and apparent distance of the object from the observer.

(dd) Overlapping of contours or interposition of objects. When one object is seen to overlap another, the object which is being overlapped is farther away. Stated another way, any object which is partly concealed by another object is determined to be behind the object being seen clearly. Disappearing or flickering landing area lights may indicate barriers between your aircraft and the area.

3. Aerial Perspective. The clarity of an object and the shadow cast by the object are perceived by the brain and used as cues for estimating distance. Factors used to determine distance using these aerial perspectives are:

(aa) Variation in Color or Shade. Even in daylight, color and shading fade with distance. Also, subtle variations which exist are discernible close-up but as distance increases these distinctions blur.

(bb) Loss of detail or texture. As you get farther from an object, discrete details become less apparent. For example, a cornfield becomes a solid color, the leaves and branches of a tree become a solid mass, and the object is judged to be at a great distance.

(cc) Light and Shadows. Every object will cast a shadow if there is a source of light. The direction the shadow is cast depends on the position of the light source. If a shadow of an object is toward the observer, the object is closer to the observer than the light source. (No duh!)

4. Motion parallax. This cue to depth perception is often considered the most important. Motion parallax refers to the apparent relative notion of stationary objects as viewed by an observer moving across the landscape. The rate of apparent movement depends on the distance the observer is from the object. Objects near the aircraft move rapidly, while distant objects appear to be almost stationary. Thus objects that appear to be moving rapidly are judged to be near while those moving slowly are judged to be at a greater distance. For example, when flying low-level,, objects near the aircraft appear to rush past while more distant objects may appear stationary. As you fly over a power line that extends to the horizon, that part of the power line that is near the aircraft appears to be moving swiftly, opposite the path of notion. Toward the horizon, the same power line will appear fixed.

(g) Dark Adaptation, Night Vision Protection, and Central Night Blind Spot.

1. Dark Adaptation - is the process by which eyes increase sensitivity to low-levels of illumination. Rhodopsin (visual purple) is the substance in the rods responsible for light sensitivity. The degree of dark adaptation increases as the amount of visual purple in the rods increases through biochemical reactions. Maximum dark adaptation is reached in about 30 to 45 minutes under minimal lighting conditions. If the dark-adapted eye is exposed to a bright light, the sensitivity of that eye is temporarily impaired. The amount of impairment depends on the intensity and duration of the exposure. Brief flashes from a white (Xenon) strobe light commonly found on aircraft have minimal effect upon night vision because the pulses of energy are of such short duration. On the other hand, exposure to a flare, a searchlight beam, or lightning may seriously impair your night vision. The recovery of a previous maximum level of dark adaptation could take from 5 to 45 minutes in continued darkness. Night vision goggles affect dark adaptation. If you dark-adapt before donning the goggles and remove them in a darkened environment, you can expect to regain full dark adaptation in about two minutes.

2. Protection of Night Vision. Repeated exposure to bright sunlight has an increasingly adverse effect on dark adaptation. This effect is intensified by reflective surfaces such as sand or snow. Exposure to intense sunlight for two to five hours decreases scotopic sensitivity for as long as five hours. Also, a decrease occurs in the rate of dark adaptation and degree of adaptive capacity. These effects are cumulative and may persist for several days. If night flight is anticipated, crewmembers should wear neutral density sunglasses when exposed to bright sunlight. Dark adaptation and retinal sensitivity are directly related to oxygen levels. Remember that one of the first symptoms of hypoxia is loss of night vision, which occurs at pressure altitudes of around 4,000 ft. After dark adaptation, crewmembers should protect their night vision by avoiding areas of high illumination, and, if unavoidable, cover or close one eye to preserve night vision in that eye. Crews should also avoid self-imposed stresses as much as possible, as they can affect the ability of the body to dark adapt or the stamina and discipline required to employ night vision techniques.

(h) Helmet Display Optimization. 

(i) FLIR Sensor Optimization. 

(j) Infrared Characteristics and FLIR Interpretation. 

(k) PNVS Characteristics and Operation. 

(l) Flight Symbology and Modes. 

(m) Aircrew Night and NVD Requirements.  See your local SOPs and your individual IATF.

(n) NVD Limitations and Techniques.

(o) Parallax Effect.

(p) Weapons Deployment During Night and NVD Operations.

(10) Maintenance Test Flight Troubleshooting and System Operations (TM 1-1520-237-23 series, TM 1-1520-253-23 series, TM 1-1520-237-MTF, TM 1-1520-253-MTF)

(a) Engine Start.

(b) Instrument Indications.

(c) Electrical System.

(d) Caution Panel Indications.

(e) Power Plant.

(f) Engine Performance Check.

(g) Power Train.

(h) Hydraulic System.

(i) Flight Controls.

(j) Vibrations.

(k) Fuel System.

(l) Communication and Navigation Equipment.

(m) DASE and HARS.

(n) Fault Detection and Location System.

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