HomeContact UsEmail Us
Flight Training

SitemapStudent Login
Online FIRC
Live Chat Software

American Flyers is happy to provide Chapter 1 from the Instrument Flying Handbook, an FAA Publication

Chapter 1Chapter 2Chapter 3Chapter 4Chapter 5Chapter 6Chapter 7Chapter 8Chapter 9Chapter 10Chapter 11




This Instrument Flying Handbook is designed for use by instrument flight instructors and pilots preparing for instrument rating tests. Instructors may find this handbook a valuable training aid as it includes basic reference material for knowledge testing and instrument flight training. Other Federal Aviation Administration (FAA) publications should be consulted for more detailed information on related topics.

This handbook conforms to pilot training and certification concepts established by the FAA. There are different ways of teaching, as well as performing, flight procedures and maneuvers and many variations in the explanations of aerodynamic theories and principles. This handbook adopts selected methods and concepts for instrument flying. The discussion and explanations reflect the most commonly used practices and principles. Occasionally the word “must” or similar language is used where the desired action is deemed critical. The use of such language is not intended to add to, interpret, or relieve a duty imposed by Title 14 of the Code of Federal Regulations (14 CFR).

All of the aeronautical knowledge and skills required to operate in instrument meteorological conditions (IMC) are detailed. Chapters are dedicated to human and aerodynamic factors affecting instrument flight, the flight instruments, attitude instrument flying for airplanes, basic flight maneuvers used in IMC, attitude instrument flying for helicopters, navigation systems, the National Airspace System (NAS), the air traffic control (ATC) system, instrument flight rules (IFR) flight procedures, and IFR emergencies. Clearance shorthand and an integrated instrument lesson guide are also included.

This handbook supersedes Advisory Circular (AC) 61-27C, Instrument Flying Handbook, which was revised in 1980. Comments regarding this handbook should be sent to U.S. Department of Transportation, Federal Aviation Administration, Airman Testing Standards Branch, AFS-630, P.O. Box 25082, Oklahoma City, OK 73125.

The current Flight Standards Service airman training and testing material and subject matter knowledge codes for all airman certificates and ratings can be obtained from the Flight Standards Service web site at: http://afs600.faa.gov.

This publication may be purchased from the Superintendent of Documents, P.O. Box 371954, Pittsburgh, PA 15250-7954, or from the U.S. Government Printing Office (GPO) bookstores located in major cities throughout the United States.

AC 00-2, Advisory Circular Checklist, transmits the current status of FAA ACs and other flight information publications. This checklist is free of charge and may be obtained by sending a request to U.S. Department of Transportation, Subsequent Distribution Office, SVC-121.23, Ardmore East Business Center, 3341 Q 75th Avenue, Landover, MD 20785. The checklist is also available on the internet at: http://www. faa.gov/abc/ac-chklst/actoc.htm.


This book was produced as a combined FAA and industry effort.


Is an Instrument Rating Necessary?

The answer to this question depends entirely upon individual needs. Pilots who fly in familiar uncongested areas, stay continually alert to weather developments, and accept an alternative to their original plan, may not need an Instrument Rating. However, some cross-country destinations may take a pilot to unfamiliar airports and/or through high activity areas in marginal visual or instrument meteorological conditions (IMC). Under these conditions, an Instrument Rating may be an alternative to rerouting, rescheduling, or canceling a flight. Many accidents are the result of pilots who lack the necessary skills or equipment to fly in marginal visual meteorological conditions (VMC) or IMC conditions and attempt flight without outside references.

Pilots originally flew aircraft strictly by sight, sound, and feel while comparing the aircraft’s attitude to the natural horizon. As aircraft performance increased, pilots required more in-flight information to enhance the safe operation of their aircraft. This information has ranged from a string tied to a wing strut, to development of sophisticated electronic flight information systems (EFIS) and flight management systems (FMS). Interpretation of the instruments and aircraft control have advanced from the “one, two, three” or “needle, ball and airspeed” system to the use of “attitude instrument flying” techniques.

Navigation began by using ground references with dead reckoning and has led to the development of electronic navigation systems. These include the automatic direction finder (ADF), very-high frequency omnidirectional range (VOR), distance measuring equipment (DME), tactical air navigation (TACAN), long range navigation (LORAN), global positioning system (GPS), instrument landing system (ILS), microwave landing system (MLS), and inertial navigation system (INS).

Perhaps you want an Instrument Rating for the same basic reason you learned to fly in the first place—because you like flying. Maintaining and extending your proficiency, once you have the rating, means less reliance on chance and more on skill and knowledge. Earn the rating—not because you might need it sometime, but because it represents achievement and provides training you will use continually and build upon as long as you fly. But most importantly —it means greater safety in flying.

Instrument Rating Requirements

A Private or Commercial pilot who operates an aircraft using an instrument flight rules (IFR) flight plan operates in conditions less than the minimums prescribed for visual flight rules (VFR), or in any flight in Class A airspace, must have an Instrument Rating and meet the appropriate currency requirements.

You will need to carefully review the aeronautical knowledge and experience requirements for the Instrument Rating as outlined in Title 14 of the Code of Federal Regulations (14 CFR) part 61. After completing the FAA Knowledge Test issued for the Instrument Rating, and all the experience requirements have been satisfied, you are eligible to take the practical test. The regulations specify minimum total and pilot in command time requirements. This minimum applies to all applicants — regardless of ability or previous aviation experience.

Training for the Instrument Rating

A person who wishes to add the Instrument Rating to their pilot certificate must first make commitments of time, money, and quality of training. There are many combinations of training methods available. Self-study alone may be adequate preparation to pass the required FAA Knowledge Test for the Instrument Rating. Occasional periods of ground and flight instruction may provide the skills necessary to pass the required test. Or, individuals may choose a training facility that provides comprehensive aviation education and the training necessary to ensure the pilot will pass all the required tests and operate safely in the National Airspace System (NAS). The aeronautical knowledge may be administered by educational institutions, aviation-oriented schools, correspondence courses, and appropriately-rated instructors. Each person must decide for themselves which training program best meets their needs and at the same time maintain a high quality of training. Interested persons should make inquiries regarding the available training at nearby airports, training facilities, in aviation publications, and through the Federal Aviation Administration (FAA) Flight Standards District Office (FSDO).

Although the regulations specify minimum requirements, the amount of instructional time needed is determined not by the regulation, but by the individual’s ability to achieve a satisfactory level of proficiency. A professional pilot with diversified flying experience may easily attain a satisfactory level of proficiency in the minimum time required by regulation. Your own time requirements will depend upon a variety of factors, including previous flying experience, rate of learning, basic ability, frequency of flight training, type of aircraft flown, quality of ground school training, and quality of flight instruction, to name a few. The total instructional time you will need, and in general the scheduling of such time, is up to the individual most qualified to judge your proficiency — the instructor who supervises your progress and endorses your record of flight training.

You can accelerate and enrich much of your training by informal study. An increasing number of visual aids and programmed instrument courses are available. The best course is one that includes a well-integrated flight and ground school curriculum. The sequential nature of flying requires that each element of knowledge and skill be learned and applied in the right manner at the right time.

Part of your instrument training may utilize a flight simulator, flight training device, or a personal computer-based aviation training device (PCATD). This ground-based flight training equipment is a valuable tool for developing your instrument cross-check and learning procedures such as intercepting and tracking, holding patterns, and instrument approaches. Once these concepts are fully understood, you can then continue with in-flight training and refine these techniques for full transference of your new knowledge and skills.

Holding the Instrument Rating does not necessarily make you a competent weather pilot. The rating certifies only that you have complied with the minimum experience requirements, that you can plan and execute a flight under IFR, that you can execute basic instrument maneuvers, and that you have shown acceptable skill and judgment in performing these activities. Your Instrument Rating permits you to fly into instrument weather conditions with no previous instrument weather experience. Your Instrument Rating is issued on the assumption that you have the good judgment to avoid situations beyond your capabilities. The instrument training program you undertake should help you not only to develop essential flying skills but also help you develop the judgment necessary to use the skills within your own limits.

Regardless of the method of training selected, the curriculum in appendix 2 provides guidance as to the minimum training required for the addition of an Instrument Rating to a Private or Commercial pilot certificate.

Maintaining the Instrument Rating

Once you hold the Instrument Rating, you may not act as pilot in command under IFR or in weather conditions less than the minimums prescribed for VFR, unless you meet the recent flight experience requirements outlined in part 61. These procedures must be accomplished within the preceding 6 months and include six instrument approaches, holding procedures, and intercepting and tracking courses through the use of navigation systems. If you do not meet the experience requirements during these 6 months, you have another 6 months to meet these minimums. If the requirements still are not met, you must pass an instrument proficiency check, which is an in-flight evaluation by a qualified instrument flight instructor using tasks outlined in the instrument rating practical test standards (PTSs).

The instrument currency requirements must be accomplished under actual or simulated instrument conditions. You may log instrument flight time during the time for which you control the aircraft solely by reference to the instruments. This can be accomplished by wearing a view-limiting device such as a hood, flying an approved flight-training device, or flying in actual IMC.

It takes only one harrowing experience to clarify the distinction between minimum practical knowledge and a thorough understanding of how to apply the procedures and techniques used in instrument flight. Your instrument training is never complete; it is adequate when you have absorbed every foreseeable detail of knowledge and skill to ensure a solution will be available if and when you need it.

Chapter 1

Human Factors


Human factors is a broad field that studies the interaction between people and machines for the purpose of improving performance and reducing errors. As aircraft became more reliable and less prone to mechanical failure, the percentage of accidents related to human factors increased. Some aspect of human factors now accounts for over 80 percent of all accidents. Pilots who have a good understanding of human factors are better equipped to plan and execute a safe and uneventful flight.

Flying in instrument meteorological conditions (IMC) can result in sensations that are misleading to the body’s sensory system. A safe pilot needs to understand these sensations and effectively counteract them. Instrument flying requires a pilot to make decisions using all available resources.

The elements of human factors covered in this chapter include sensory systems used for orientation, illusions in flight, physiological and psychological factors, medical factors, aeronautical decision making, and crew/cockpit resource management.

Human factors: A multidisciplinary field encompassing the behavioral and social sciences, engineering, and physiology, to consider the variables that influence individual and crew performance for the purpose of reducing errors.

Sensory Systems for Orientation

Orientation: is the awareness of the position of the aircraft and of oneself in relation to a specific reference point. Disorientation is the lack of orientation, and spatial disorien-tation specifically refers to the lack of orientation with regard to position in space and to other objects.

Orientation is maintained through the body’s sensory organs in three areas: visual, vestibular, and postural. The eyes maintain visual orientation; the motion sensing system in the inner ear maintains vestibular orientation; and the nerves in the skin, joints, and muscles of the body maintain postural orientation. When human beings are in their natural environment, these three systems work well. However, when the human body is subjected to the forces of flight, these senses can provide misleading information. It is this misleading information that causes pilots to become disoriented.


During flight in visual meteorological conditions (VMC), the eyes are the major orientation source and usually provide accurate and reliable information. Visual cues usually prevail over false sensations from other sensory systems. When these visual cues are taken away, as they are in IMC, false sensations can cause the pilot to quickly become disoriented.

Orientation: Awareness of the position of the aircraft and of oneself in relation to a specific reference point.

Spatial disorientation: The state of confusion due to misleading information being sent to the brain from various sensory organs, resulting in a lack of awareness of the aircraft position in relation to a specific reference point.

The only effective way to counter these false sensations is to recognize the problem, disregard the false sensations, and while relying totally on the flight instruments, use the eyes to determine the aircraft attitude. The pilot must have an understanding of the problem and the self-confidence to control the aircraft using only instrument indications.


The inner ear has two major parts concerned with orientation, the semicircular canals and the otolith organs. [Figure 1-1] The semicircular canals detect angular acceleration of the body while the otolith organs detect linear acceleration and gravity. The semicircular canals consist of three tubes at right angles to each other, each located on one of the three axes: pitch, roll, or yaw. Each canal is filled with a fluid called endolymph fluid. In the center of the canal is the cupola, a gelatinous structure that rests upon sensory hairs located at the end of the vestibular nerves.

Figure 1-2 illustrates what happens during a turn. When the ear canal is moved in its plane, the relative motion of the fluid moves the cupola, which, in turn, stimulates the sensory hairs to provide the sensation of turning. This effect can be demonstrated by taking a glass filled with water and turning it slowly. The wall of the glass is moving, yet the water is not. If these sensory hairs were attached to the glass, they would be moving in relation to the water, which is still standing still.

Vestibular: The central cavity of the bony labyrinth of the ear, or the parts of the membranous labyrinth that it contains.

Figure 1-2. Angular acceleration.

The ear was designed to detect turns of a rather short duration. After a short period of time (approximately 20 seconds), the fluid accelerates due to friction between the fluid and the canal wall. Eventually, the fluid will move at the same speed as the ear canal. Since both are moving at the same speed, the sensory hairs detect no relative movement and the sensation of turning ceases. This can also be illustrated with the glass of water. Initially, the glass moved and the water did not. Yet, contin-ually turning the glass would result in the water accelerating and matching the speed of the wall of the glass.

The pilot is now in a turn without any sensation of turning. When the pilot stops turning, the ear canal stops moving but the fluid does not. The motion of the fluid moves the cupola and therefore, the sensory hairs in the opposite direction. This creates the sensation of turning in the opposite direction even though the turn has stopped.

The otolith organs detect linear acceleration and gravity in a similar way. Instead of being filled with a fluid, a gelatinous membrane containing chalk-like crystals covers the sensory hairs. When the pilot tilts his/her head, the weight of these crystals causes this membrane to shift due to gravity and the sensory hairs detect this shift. The brain orients this new position to what it perceives as vertical. Acceleration and deceleration also cause the membrane to shift in a similar manner. Forward acceleration gives the illusion of the head tilting backward. [Figure 1-3]


Nerves in the body’s skin, muscles, and joints constantly send signals to the brain, which signals the body’s relation to gravity. These signals tell the pilot his/her current position. Acceleration will be felt as the pilot is pushed back into the seat. Forces created in turns can lead to false sensations of the true direction of gravity, and may give the pilot a false sense of which way is up.

Uncoordinated turns, especially climbing turns, can cause misleading signals to be sent to the brain. Skids and slips give the sensation of banking or tilting. Turbulence can create motions that confuse the brain as well. Pilots need to be aware that fatigue or illness can exacerbate these sensations and ultimately lead to subtle incapacitation.

Illusions Leading to Spatial Disorientation

The sensory system responsible for most of the illusions leading to spatial disorientation is the vestibular system in the inner ear. The major illusions leading to spatial disorientation are covered below.

Inner Ear

The Leans

A condition called the leans can result when a banked attitude, to the left for example, may be entered too slowly to set in motion the fluid in the “roll” semicircular tubes. [Figure 1-2] An abrupt correction of this attitude can now set the fluid in motion, creating the illusion of a banked attitude to the right. The disoriented pilot may make the error of rolling the aircraft into the original left-banked attitude or, if level flight is maintained, will feel compelled to lean to the left until this illusion subsides.

Coriolis Illusion

The pilot has been in a turn long enough for the fluid in the ear canal to move at the same speed as the canal. A movement of the head in a different plane, such as looking at something in a different part of the cockpit, may set the fluid moving thereby creating the strong illusion of turning or accelerating on an entirely different axis. This is called Coriolis illusion. This action causes the pilot to think the aircraft is doing a maneuver that it is not. The disoriented pilot may maneuver the aircraft into a dangerous attitude in an attempt to correct the aircraft’s perceived attitude.

For this reason, it is important that pilots develop an instrument cross-check or scan that involves minimal head movement. Take care when retrieving charts and other objects in the cockpit—if you drop something, retrieve it with minimal head movement and be alert for the Coriolis illusion.

Graveyard Spiral

As in other illusions, a pilot in a prolonged coordinated, constant-rate turn, will have the illusion of not turning. During the recovery to level flight, the pilot will experience the sensation of turning in the opposite direction. The disoriented pilot may return the aircraft to its original turn.

Leans: An abrupt correction of a Coriolis illusion: An abrupt head banked attitude, entered too slowly movement, while in a prolonged to stimulate the motion sensing constant-rate turn that has ceased system in the inner ear, can create stimulating the motion sensing the illusion of banking in the system, can create the illusion of opposite direction. rotation or movement in an entirely different axis.

aircraft tends to lose altitude in turns unless the pilot compensates for the loss in lift, the pilot may notice a loss of altitude. The absence of any sensation of turning creates the illusion of being in a level descent. The pilot may pull back on the controls in an attempt to climb or stop the descent. This action tightens the spiral and increases the loss of altitude; hence, this illusion is referred to as a graveyard spiral. At some point, this could lead to a loss of control by the pilot.

Somatogravic Illusion

A rapid acceleration, such as experienced during takeoff, stimulates the otolith organs in the same way as tilting the head backwards. This action creates the somatogravic illusion of being in a nose-up attitude, especially in situations without good visual references. The disoriented pilot may push the aircraft into a nose-low or dive attitude. A rapid deceleration by quick reduction of the throttle(s) can have the opposite effect, with the disoriented pilot pulling the aircraft into a nose-up or stall attitude.

Inversion Illusion

An abrupt change from climb to straight-and-level flight can stimulate the otolith organs enough to create the illusion of tumbling backwards, or inversion illusion. The disoriented pilot may push the aircraft abruptly into a nose-low attitude, possibly intensifying this illusion.

Elevator Illusion

An abrupt upward vertical acceleration, as can occur in an updraft, can stimulate the otolith organs to create the illusion of being in a climb. This is called elevator illusion. The disoriented pilot may push the aircraft into a nose-low attitude. An abrupt downward vertical acceleration, usually in a downdraft, has the opposite effect, with the disoriented pilot pulling the aircraft into a nose-up attitude.


Two illusions that lead to spatial disorientation, the false horizon and autokinesis, are concerned with the visual system.

Graveyard spiral: The illusion of Inversion illusion: The feeling the cessation of a turn while actually that the aircraft is tumbling still in a prolonged coordinated, backwards, caused by an abrupt constant-rate turn, which can lead a change from climb to straight-and-disoriented pilot to a loss of control level flight while in situations of the aircraft. lacking visual reference.

Somatogravic illusion: The feeling Elevator illusion: The feeling of of being in a nose-up or nose-down being in a climb or descent, caused attitude, caused by a rapid accelera-by the kind of abrupt vertical tion or deceleration while in flight accelerations that result from up-situations that lack visual reference. or downdrafts.

False Horizon

A sloping cloud formation, an obscured horizon, an aurora borealis, a dark scene spread with ground lights and stars, and certain geometric patterns of ground lights can provide inaccurate visual information, or false horizon, for aligning the aircraft correctly with the actual horizon. The disoriented pilot may place the aircraft in a dangerous attitude.


In the dark, a stationary light will appear to move about when stared at for many seconds. The disoriented pilot could lose control of the aircraft in attempting to align it with the false movements of this light, called autokinesis.


The postural system sends signals from the skin, joints, and muscles to the brain that are interpreted in relation to the Earth’s gravitational pull. These signals determine posture. Inputs from each movement update the body’s position to the brain on a constant basis. “Seat of the pants” flying is largely dependent upon these signals. Used in conjunction with visual and vestibular clues, these sensations can be fairly reliable. However, because of the forces acting upon the body in certain flight situations, many false sensations can occur due to acceleration forces overpowering gravity. [Figure 1-4] These situations include uncoordinated turns, climbing turns, and turbulence.

False horizon: Inaccurate visual Autokinesis: Nighttime visual information for aligning the aircraft illusion that a stationary light is caused by various natural and moving, which becomes apparent geometric formations that disorient after several seconds of staring the pilot from the actual horizon. at the light.

Demonstrating Spatial Disorientation

There are a number of controlled aircraft maneuvers a pilot can perform to experiment with spatial disorientation. While each maneuver will normally create a specific illusion, any false sensation is an effective demonstration of disorien-tation. Thus, even if there is no sensation during any of these maneuvers, the absence of sensation is still an effective demonstration in that it shows the inability to detect bank or roll. There are several objectives in demonstrating these various maneuvers.



  1. They teach pilots to understand the susceptibility of the human system to spatial disorientation.

  2. They demonstrate that judgments of aircraft attitude based on bodily sensations are frequently false.

  3. They can help to lessen the occurrence and degree of disorientation through a better understanding of the relationship between aircraft motion, head movements, and resulting disorientation.

  4. They can help to instill a greater confidence in relying on flight instruments for assessing true aircraft attitude.

A pilot should not attempt any of these maneuvers at low altitudes, or in the absence of an instructor pilot or an appropriate safety pilot.

Climbing While Accelerating

With the pilot’s eyes closed, the instructor pilot maintains approach airspeed in a straight-and-level attitude for several seconds, and then accelerates while maintaining straight-and-level attitude. The usual illusion during this maneuver, without visual references, will be that the aircraft is climbing.

Climbing While Turning

With the pilot’s eyes still closed and the aircraft in a straight-and-level attitude, the instructor pilot now executes, with a relatively slow entry, a well-coordinated turn of about 1.5 positive G (approximately 50°bank) for 90°. While in the turn, without outside visual references and under the effect of the slight positive G, the usual illusion produced is that of a climb. Upon sensing the climb, the pilot should immediately open the eyes and see that a slowly established, coordinated turn produces the same feeling as a climb.

Demonstrating Spatial Disorientation—Safety Check

These demonstrations should never be conducted at low altitudes, or without an instructor pilot or appropriate safety pilot onboard.

Diving While Turning

This sensation can be created by repeating the previous procedure, with the exception that the pilot’s eyes should be kept closed until recovery from the turn is approximately one-half completed. With the eyes closed, the usual illusion will be that the aircraft is diving.

Tilting to Right or Left

While in a straight-and-level attitude, with the pilot’s eyes closed, the instructor pilot executes a moderate or slight skid to the left with wings level. The usual illusion is that the body is being tilted to the right.

Reversal of Motion

This illusion can be demonstrated in any of the three planes of motion. While straight-and-level, with the pilot’s eyes closed, the instructor pilot smoothly and positively rolls the aircraft to approximately a 45°-bank attitude while main-taining heading and pitch attitude. The usual illusion is a strong sense of rotation in the opposite direction. After this illusion is noted, the pilot should open the eyes and observe that the aircraft is in a banked attitude.

Diving or Rolling Beyond the Vertical Plane

This maneuver may produce extreme disorientation. While in straight-and-level flight, the pilot should sit normally, either with eyes closed or gaze lowered to the floor. The instructor pilot starts a positive, coordinated roll toward a 30°or 40°angle of bank. As this is in progress, the pilot should tilt the head forward, look to the right or left, then immediately return the head to an upright position. The instructor pilot should time the maneuver so the roll is stopped just as the pilot returns his/her head upright. An intense disorientation is usually produced by this maneuver, with the pilot experi-encing the sensation of falling downwards into the direction of the roll.

In the descriptions of these maneuvers, the instructor pilot is doing the flying, but having the pilot do the flying can also make a very effective demonstration. The pilot should close his/her eyes and tilt the head to one side. The instructor pilot tells the pilot what control inputs to perform. The pilot then attempts to establish the correct attitude or control input with eyes still closed and head still tilted. While it is clear the pilot has no idea of the actual attitude, he/she will react to what the senses are saying. After a short time, the pilot will become disoriented and the instructor pilot then tells the pilot to look up and recover. The benefit of this exercise is the pilot actually experiences the disorientation while flying the aircraft.

Top of the Page

Coping with Spatial Disorientation

Pilots can take action to prevent illusions and their potentially disastrous consequences if they:

  1. Understand the causes of these illusions and remain constantly alert for them.

  2. Always obtain preflight weather briefings.

  3. Do not continue flight into adverse weather conditions or into dusk or darkness unless proficient in the use of flight instruments.

  4. Ensure that when outside visual references are used, they are reliable, fixed points on the Earth’s surface.

  5. Avoid sudden head movement, particularly during takeoffs, turns, and approaches to landing.

  6. Remember that illness, medication, alcohol, fatigue, sleep loss, and mild hypoxia is likely to increase susceptibility to spatial disorientation.

  7. Most importantly, become proficient in the use of flight instruments and rely upon them.

The sensations, which lead to illusions during instrument flight conditions, are normal perceptions experienced by pilots. These undesirable sensations cannot be completely prevented, but through training and awareness, pilots can ignore or suppress them by developing absolute reliance on the flight instruments. As pilots gain proficiency in instrument flying, they become less susceptible to these illusions and their effects.

Practice Makes Proficient

Through training and awareness in developing absolute reliance on the instruments, pilots can reduce their susceptibility to disorienting illusions.

Optical Illusions

Of the senses, vision is the most important for safe flight. However, various terrain features and atmospheric conditions can create optical illusions. These illusions are primarily associated with landing. Since pilots must transition from reliance on instruments to visual cues outside the cockpit for landing at the end of an instrument approach, it is imperative they are aware of the potential problems associated with these illusions, and take appropriate corrective action. The major illusions leading to landing errors are described below.

Runway Width Illusion

A narrower-than-usual runway can create an illusion the aircraft is at a higher altitude than it actually is, especially when runway length-to-width relationships are comparable. [Figure 1-5A] The pilot who does not recognize this illusion will fly a lower approach, with the risk of striking objects along the approach path or landing short. A wider-than-usual runway can have the opposite effect, with the risk of leveling out high and landing hard, or overshooting the runway.

Runway and Terrain Slopes Illusion

An upsloping runway, upsloping terrain, or both, can create an illusion the aircraft is at a higher altitude than it actually is. [Figure 1-5B] The pilot who does not recognize this illusion will fly a lower approach. Downsloping runways and downsloping approach terrain can have the opposite effect.

Featureless Terrain Illusion

An absence of surrounding ground features, as in an overwater approach, over darkened areas, or terrain made featureless by snow, can create an illusion the aircraft is at a higher altitude than it actually is. This illusion, sometimes referred to as the “black hole approach,” causes pilots to fly a lower approach than is desired.

Water Refraction

Rain on the windscreen can create an illusion of being at a higher altitude due to the horizon appearing lower than it is. This can result in the pilot flying a lower approach.

Optical illusion: (in aircraft flight)

A misleading visual image of features on the ground associated with landing, which causes a pilot to misread the spatial relationships between the aircraft and the runway.

Normal approach Approach due to illusion


Atmospheric haze can create an illusion of being at a greater distance from the runway. As a result, the pilot will have a tendency to be high on the approach. Conversely, extremely clear air can give the pilot the illusion of being closer than he/she actually is, resulting in a long, low approach. The diffusion of light due to water particles can adversely affect depth perception. The lights and terrain features normally used to gauge height during landing become less effective for the pilot.


Penetration of fog can create an illusion of pitching up. Pilots who do not recognize this illusion will often steepen the approach quite abruptly.

Ground Lighting Illusions

Lights along a straight path, such as a road, and even lights on moving trains can be mistaken for runway and approach lights. Bright runway and approach lighting systems, especially where few lights illuminate the surrounding terrain, may create the illusion of less distance to the runway. The pilot who does not recognize this illusion will often fly a higher approach.

Top of the Page

How to Prevent Landing Errors Due to Visual Illusions

Pilots can take action to prevent these illusions and their potentially hazardous consequences if they:

  1. Anticipate the possibility of visual illusions during approaches to unfamiliar airports, particularly at night or in adverse weather conditions. Consult airport diagrams and the Airport/Facility Directory (A/FD) for information on runway slope, terrain, and lighting.

  2. Make frequent reference to the altimeter, especially during all approaches, day and night.

  3. If possible, conduct aerial visual inspection of unfamiliar airports before landing.

  4. Use Visual Approach Slope Indicator (VASI) or Precision Approach Path Indicator (PAPI) systems for a visual reference, or an electronic glide slope, whenever they are available.

Visual Approach Slope Indicator Precision Approach Path Indicator (VASI): A system of lights arranged (PAPI): Similar to the VASI but to provide visual descent guidance consisting of one row of lights in two-information during the approach to or four-light systems. A pilot on the the runway. A pilot on the correct correct glide slope will see two white glide slope will see red lights over lights and two red lights. white lights.

  1. Utilize the visual descent point (VDP) found on many nonprecision instrument approach procedure charts.

  2. Recognize that the chances of being involved in an approach accident increase when some emergency or other activity distracts from usual procedures.

  3. Maintain optimum proficiency in landing procedures.

Vision Under Dim and Bright Illumination

Under conditions of dim illumination, aeronautical charts and aircraft instruments can become unreadable unless adequate cockpit lighting is available. In darkness, vision becomes more sensitive to light; this process is called dark adap-tation. Although exposure to total darkness for at least 30 minutes is required for complete dark adaptation, a pilot can achieve a moderate degree of dark adaptation within 20 minutes under dim red cockpit lighting. Red light distorts colors, especially on aeronautical charts, and makes it very difficult for the eyes to focus on objects inside the aircraft. Pilots should use it only where optimum outside night vision capability is necessary. White cockpit lighting should be available when needed for map and instrument reading, especially under IMC conditions.

Dark adaptation is impaired by exposure to cabin pressure altitudes above 5,000 feet, carbon monoxide inhaled through smoking and from exhaust fumes, deficiency of Vitamin A in the diet, and by prolonged exposure to bright sunlight. Since any degree of dark adaptation is lost within a few seconds of viewing a bright light, pilots should close one eye when using a light to preserve some degree of night vision. During night flights in the vicinity of lightning, cockpit lights should be turned up to help prevent loss of night vision due to the bright flashes.

Physiological and Psychological Factors

Several factors can affect the pilot, either physiologically or psychologically, to the point where the safety of a flight can be severely compromised. These factors are stress, medical, alcohol, and fatigue. Any of these factors, individually or in combination, can significantly degrade the pilot’s decision-making or flying abilities, both in the flight planning phase and in flight.

Dark adaptation: Physical and chemical adjustments of the eye that make vision possible in relative darkness.


Stress is the body’s response to demands placed upon it. These demands can be either pleasant or unpleasant in nature. The causes of stress for a pilot can range from unexpected weather or mechanical problems while in flight, to personal issues totally unrelated to flying. Stress is an inevitable and necessary part of life; it adds motivation to life and heightens a pilot’s response to meet any challenge. The effects of stress are cumulative, and there is a limit to a pilot’s adaptive nature. This limit, the stress tolerance level, is based on a pilot’s ability to cope with the situation.

At first, some amount of stress can be desirable and can actually improve performance. Higher stress levels, particularly over long periods of time, can adversely affect performance. Performance will generally increase with the onset of stress, but will peak and then begin to fall off rapidly as stress levels exceed the ability to cope. [Figure 1-6A]

At the lower stress levels, boredom is followed by optimal performance at the moderate stress levels, then followed ultimately by overload and panic at the highest stress levels. At this point, a pilot’s performance begins to decline and judgment deteriorates. Complex or unfamiliar tasks require higher levels of performance than simple or overlearned tasks. Complex or unfamiliar tasks are also more subject to the adverse effects of increasing stress than simple or familiar tasks. [Figure 1-6B]

The indicators of excessive stress often show as three types of symptoms: (1) emotional, (2) physical, and (3) behavioral. These symptoms depend upon whether aggression is focused inward or outward. Individuals who typically turn their aggressive feelings inward often demonstrate the emotional symptoms of depression, preoccupation, sadness, and withdrawal. Individuals who typically take out their frustration on other people or objects exhibit few physical symptoms. Emotional symptoms may surface as over-compensation, denial, suspicion, paranoia, agitation, restlessness, defensiveness, excess sensitivity to criticism, argumentativeness, arrogance, and hostility. Pilots need to learn to recognize the symptoms of stress as they begin to occur within themselves.

Stress: The body’s response to demands placed upon it.








There are many techniques available that can help reduce stress in life or help people cope with it better. Not all of the following ideas may be the solution, but some of them should be effective.

  • Become knowledgeable about stress
  • Take a realistic self-assessment
  • Take a systematic approach to problem solving
  • Develop a lifestyle that will buffer against the effects of stress
  1. Practice behavior management techniques.

  2. Establish and maintain a strong support network.

Good cockpit stress management begins with good life stress management. Many of the stress-coping techniques practiced for life stress management are not usually practical in flight. Rather, pilots must condition themselves to relax and think rationally when stress appears. The following checklist outlines some methods of cockpit stress management.

  1. Avoid situations that distract from flying the aircraft.

  2. Reduce workload to reduce stress levels. This will create a proper environment in which to make good decisions.

  3. If an emergency does occur, be calm. Think for a moment, weigh the alternatives, then act.

  4. Become thoroughly familiar with the aircraft, its operation, and emergency procedures. Also, maintain flight proficiency to build confidence.

  5. Know and respect personal limits.

  6. Do not allow small mistakes to be distractions during flight; rather, review and analyze them after landing.

  7. If flying adds stress, either stop flying or seek professional help to manage stress within acceptable limits.

Top of the Page

Medical Factors

A “go/no-go” decision is made before each flight. The pilot should not only preflight check the aircraft, but also his/ herself before every flight. As a pilot you should ask yourself, “Could I pass my medical examination right now?” If you cannot answer with an absolute “yes,” then you should not fly. This is especially true for pilots embarking on flights in IMC. Instrument flying can be much more demanding than flying in VMC, and peak performance is critical for the safety of flight.

Pilot performance can be seriously degraded by both prescribed and over-the-counter medications, as well as by the medical conditions for which they are taken. Many medications, such as tranquilizers, sedatives, strong pain relievers, and cough-suppressants, have primary effects that may impair judgment, memory, alertness, coordination, vision, and the ability to make calculations. Others, such as antihistamines, blood pressure drugs, muscle relaxants, and agents to control diarrhea and motion sickness, have side effects that may impair the same critical functions. Any medication that depresses the nervous system, such as a sedative, tranquilizer, or antihistamine, can make a pilot much more susceptible to hypoxia.

Title 14 of the Code of Federal Regulations (14 CFR) prohibits pilots from performing crewmember duties while using any medication that affects the faculties in any way contrary to safety. The safest rule is not to fly as a crew-member while taking any medication, unless approved to do so by the Federal Aviation Administration (FAA). If there is any doubt regarding the effects of any medication, consult an Aviation Medical Examiner (AME) before flying.


14 CFR part 91 prohibits pilots from performing crewmember duties within 8 hours after drinking any alcoholic beverage or while under the influence. Extensive research has provided a number of facts about the hazards of alcohol consumption and flying. As little as one ounce of liquor, one bottle of beer, or four ounces of wine can impair flying skills and render a pilot much more susceptible to disorientation and hypoxia. Even after the body completely metabolizes a moderate amount of alcohol, a pilot can still be impaired for many hours. There is simply no way of increasing the metabolism of alcohol or alleviating a hangover.


Fatigue is one of the most treacherous hazards to flight safety, as it may not be apparent to a pilot until serious errors are made. Fatigue can be either acute (short-term) or chronic (long-term). A normal occurrence of everyday living, acute fatigue is the tiredness felt after long periods of physical and mental strain, including strenuous muscular effort, immobility, heavy mental workload, strong emotional pressure, monotony, and lack of sleep. Acute fatigue is prevented by adequate rest, regular exercise, and proper nutrition. Chronic fatigue occurs when there is not enough time for a full recovery from repeated episodes of acute fatigue. Recovery from chronic fatigue requires a prolonged period of rest. In either case, unless adequate precautions are taken, personal performance could be impaired and adversely affect pilot judgment and decision making.

Hypoxia: A state of oxygen deficiency in the body sufficient to impair functions of the brain and other organs.

IMSAFE Checklist

The following checklist, IMSAFE, is intended for a pilot’s personal preflight use. A quick check of the items on this list can help the pilot make a good self-evaluation prior to any flight. If the answer to any of the checklist questions is yes, then the pilot should consider not flying.

Illness—Do I have any symptoms?

Medication—Have I been taking prescription or over-the-counter drugs?

Stress—Am I under psychological pressure from the job? Do I have money, health, or family problems?

Alcohol—Have I been drinking within 8 hours? Within 24 hours?

Fatigue—Am I tired and not adequately rested?

Eating—Have I eaten enough of the proper foods to keep adequately nourished during the entire flight?

Aeronautical Decision Making

Aeronautical decision making (ADM) is a systematic approach to the mental process used by pilots to consistently determine the best course of action in response to a given set of circumstances. ADM builds upon the foundation of conventional decision making, but enhances the process to decrease the probability of pilot error. ADM provides a structure to analyze changes that occur during a flight and determine how these changes might affect a flight’s safe outcome.

The ADM process addresses all aspects of decision making in the cockpit and identifies the steps involved in good decision making. These steps are:

  1. Identifying personal attitudes hazardous to safe flight.

  2. Learning behavior modification techniques.

  3. Learning how to recognize and cope with stress.

  4. Developing risk assessment skills.

  5. Using all resources.

  6. Evaluating the effectiveness of one’s ADM skills.

Aeronautical decision making (ADM): A systematic approach to the mental process used by pilots to consistently determine the best course of action in response to a given set of circumstances.

In conventional decision making, the need for a decision is triggered by recognition that something has changed or an expected change did not occur. Recognition of the change, or nonchange, is a vital step in any decision making process. Not noticing the change in the situation can lead directly to a mishap. [Figure 1-7A] The change indicates that an appropriate response or action is necessary in order to modify the situation (or, at least, one of the elements that comprise it) and bring about a desired new situation. Therefore, situational awareness is the key to successful and safe decision making. At this point in the process, the pilot is faced with a need to evaluate the entire range of possible responses to the detected change and to determine the best course of action.

Situational awareness: Knowing where you are in regard to location, air traffic control, weather, regulations, aircraft status, and other factors that may affect flight.

Figure 1-7B illustrates the ADM process, how this process expands conventional decision making, shows the interactions of the ADM steps, and how these steps can produce a safe outcome. Starting with the recognition of change, and following with an assessment of alternatives, a decision to act or not act is made, and the results are monitored. Pilots can use ADM to enhance their conventional decision making process because it: (1) increases their awareness of the importance of attitude in decision making; (2) teaches the ability to search for and establish relevance of information;

(3) increases their motivation to choose and execute actions that ensure safety in the situational timeframe.

The DECIDE Model

A tool to use in making good aeronautical decisions is the DECIDE Model. [Figure 1-7C] The DECIDE Model is a six-step process intended to provide the pilot with a logical way of approaching decision making. The six elements of the DECIDE Model represent a continuous loop process to assist a pilot in the decision making when faced with a change in a situation that requires judgment. The model is primarily focused on the intellectual component, but can have an impact on the motivational component of judgment as well. If a pilot continually uses the DECIDE Model in all decision making, it becomes very natural and could result in better decisions being made under all types of situations.

Hazardous Attitudes and Antidotes


Research has identified five hazardous attitudes that can affect a pilot’s judgment, as well as antidotes for each of these five attitudes. ADM addresses the following:

  1. Anti-authority (“Don’t tell me!”). This attitude is found in people who do not like anyone telling them what to do. They may be resentful of having someone tell them what to do or may regard rules, regulations, and procedures as silly or unnecessary. However, it is always your preroga-tive to question authority if you feel it is in error.

  2. Impulsivity (“Do something quickly!”). This attitude is found in people who frequently feel the need to do something— anything— immediately. They do not stop to think about what they are about to do, they do not select the best alternative, and they do the first thing that comes to mind.

Hazardous attitudes: Five attitudes that contribute to poor pilot judgment while making decisions in flight: anti-authority, impulsivity, invulnerability, “macho,” and resignation.

  1. Invulnerability (“It won’t happen to me!”). Many people feel that accidents happen to others, but never to them. They know accidents can happen, and they know that anyone can be affected. They never really feel or believe that they will be personally involved. Pilots who think this way are more likely to take chances and increase risk.

  2. Macho (“I can do it!”). Pilots who are always trying to prove that they are better than anyone else are thinking, “I can do it— I’ll show them.” Pilots with this type of attitude will try to prove themselves by taking risks in order to impress others. This pattern is characteristic in both men and women.

  3. Resignation (“What’s the use?”). These pilots do not see themselves as being able to make a great deal of difference in what happens to them. When things go well, the pilot is apt to think it is due to good luck. When things go badly, the pilot may feel that someone is out to get them, or attribute it to bad luck. The pilot will leave the action to others, for better or worse. Sometimes, such pilots will even go along with unreasonable requests just to be a “nice guy.”

Hazardous attitudes, which contribute to poor pilot judgment, can be effectively counteracted by redirecting that hazardous attitude so that correct action can be taken. Recognition of hazardous thoughts is the first step toward neutralizing them. After recognizing a thought as hazardous, the pilot should label it as hazardous, then state the corresponding antidote. Antidotes should be memorized for each of the hazardous attitudes so they automatically come to mind when needed. Each hazardous attitude along with its appropriate antidote is shown in figure 1-8.

Crew/Cockpit Resource Management

Crew/cockpit resource management (CRM) is the effective use of all available resources; human resources, hardware, and information. While CRM is primarily focused on pilots operating in crew environments, many of the elements and concepts apply to single pilot operations.

Human Resources

Human resources include all groups routinely working with pilots to ensure flight safety. These groups include, but are not limited to: weather briefers, flightline personnel, maintenance personnel, crewmembers, pilots, and air traffic personnel. Pilots must recognize the need to seek enough information from these sources to make a valid decision. After all of the necessary information has been gathered, the pilot’s decision must be passed on to those concerned, such as other aircraft, air traffic controllers, crewmembers, and passengers. The pilot may have to request assistance from others and be assertive to safely resolve some situations.

CRM focuses on communication skills, teamwork, task allocation, and decision making. The single pilot needs to be able to effectively communicate with air traffic controllers, maintenance personnel, dispatchers, and other pilots. Key components of the communication process are inquiry, advocacy, and assertion.

Pilots should understand the need to seek further information from others until satisfied they have the proper information to make the best decision. Once a pilot has gathered all pertinent information and made the appropriate decision, the pilot needs to advocate the solution to others, such as air traffic controllers, to ensure the safe outcome of the flight. Pilots need to understand they must be assertive when seeking appropriate resolutions to problems they face.


Equipment in many of today’s aircraft includes automated flight and navigation systems. These automatic systems, while providing relief from many routine cockpit tasks, present a different set of problems for pilots. Information from these systems needs to be continually monitored to ensure proper situational awareness.

Crew/cockpit resource management (CRM): The effective use of all available resources— human resources, hardware, and information.

Information Workload

Workloads need to be properly managed. The pilot flying in IMC is faced with many tasks, each with a different level of importance to the outcome of the flight. For example, a pilot preparing to execute an instrument approach to an airport needs to review the approach chart, prepare the aircraft for the approach and landing, complete checklists, obtain information from Automatic Terminal Information Service (ATIS) or air traffic control (ATC), and set the navigation radios and equipment.

The pilot who effectively manages his/her workload will complete as many of these tasks as early as possible to preclude the possibility of becoming overloaded by last minutes changes and communication priorities in the later, more critical stages of the approach. Figure 1-9 shows the margin of safety is at the minimum level during this stage of the approach. Routine tasks that have been delayed until the last minute can contribute to the pilot becoming overloaded and stressed, resulting in an erosion of performance.

By planning ahead, a pilot can effectively reduce workload during critical phases of flight. If a pilot enters the final phases of the instrument approach unprepared, the pilot should recognize the situation, abandon the approach, and try it again after becoming better prepared. Effective resource management includes recognizing hazardous situations and attitudes, decision making to promote good judgment and headwork, and managing the situation to ensure the safe outcome of the IFR flight.

Keys to Communication

Inquiry—gather pertinent information. Advocacy—promote a solution or decision. Assertion—seek resolution with firm determination.



American Flyers is happy to provide Chapter 1 from the Instrument Flying Handbook, an FAA Publication

Chapter 1Chapter 2Chapter 3Chapter 4Chapter 5Chapter 6Chapter 7Chapter 8Chapter 9Chapter 10Chapter 11

Top of the Page