10: Flight Physiology

Principles of Flight Instruction

Fitness for Flight

Supplemental Oxygen

Spatial Disorientation, Vertigo, and Visual Illusions

Motion Sickness

Collision Avoidance

Principles of Flight Instruction

“Integrated flight instruction” means that each flight maneuver should be performed by using both outside visual references and the flight instruments. When pilots use this technique, they develop proper habit patterns of instrument interpretation and aircraft control, which increases their overall piloting ability. This results in less difficulty in holding desired altitudes, controlling airspeed during takeoffs, climbs, descents, and landing approaches, and in maintaining headings in the traffic pattern, as well as on cross-country flights.

Distractions are used throughout the flight training process to help the student develop skill in maintaining control of the aircraft while his/her attention is diverted. Some appropriate distractions for flight training are:

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

Risk management is the part of the decision making process which relies on situational awareness, problem recognition, and good judgment to reduce risks associated with each flight.

The ADM process addresses all aspects of decision making in the flight deck and identifies the steps involved in good decision making. Steps for good decision making 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 in a multicrew situation.
  6. Evaluating the effectiveness of one’s ADM skills.

There are a number of classic behavioral traps into which pilots have been known to fall. Pilots, particularly those with considerable experience, as a rule always try to complete a flight as planned, please passengers, meet schedules, and generally demonstrate that they have the “right stuff.” These tendencies ultimately may lead to practices that are dangerous and often illegal, and may lead to a mishap. All experienced pilots have fallen prey to, or have been tempted by, one or more of these tendencies in their flying careers. These dangerous tendencies or behavior patterns, which must be identified and eliminated, include:

Peer pressure. Poor decision making based upon emotional response to peers rather than evaluating a situation objectively.

Mind set. The inability to recognize and cope with changes in the situation different from those anticipated or planned.

Get-there-itis. This tendency, common among pilots, clouds the vision and impairs judgment by causing a fixation on the original goal or destination combined with a total disregard for any alternative course of action.

Duck-under syndrome. The tendency to sneak a peek by descending below minimums during an approach. Based on a belief that there is always a built-in “fudge” factor that can be used or on an unwillingness to admit defeat and shoot a missed approach.

Scud running. Pushing the capabilities of the pilot and the aircraft to the limits by trying to maintain visual contact with the terrain while trying to avoid physical contact with it. This attitude is characterized by the old pilot’s joke: “If it’s too bad to go IFR, we’ll go VFR.”

Continuing visual flight rules (VFR) into instrument conditions often leads to spatial disorientation or collision with ground/obstacles. It is even more dangerous if the pilot is not instrument qualified or current.

Getting behind the aircraft. Allowing events or the situation to control your actions rather than the other way around. Characterized by a constant state of surprise at what happens next.

Loss of positional or situation awareness. Another case of getting behind the aircraft which results in not knowing where you are, an inability to recognize deteriorating circumstances, and/or the misjudgment of the rate of deterioration.

Operating without adequate fuel reserves. Ignoring minimum fuel reserve requirements, either VFR or IFR, is generally the result of overconfidence, lack of flight planning, or ignoring the regulations.

Descent below the minimum enroute altitude. The duck-under syndrome during the enroute portion of an IFR flight.

Flying outside the envelope. Unjustified reliance on the (usually mistaken) belief that the aircraft’s high performance capability meets the demands imposed by the pilot’s (usually overestimated) flying skills.

Neglect of flight planning, preflight inspections, checklists, etc. Unjustified reliance on the pilot’s short and long term memory, regular flying skills, repetitive and familiar routes, etc.

Each ADM student should take the Self-Assessment Hazardous Attitude Inventory Test in order to gain a realistic perspective on their attitudes toward flying. The inventory test requires the pilot to provide a response which most accurately reflects the reasoning behind each decision. The pilot must choose one of the five given reasons for making that decision, even though the pilot may not consider any of the five choices acceptable. The inventory test presents extreme cases of incorrect pilot decision making in an effort to introduce the five types of hazardous attitudes.

ADM addresses the following five hazardous attitudes:

  1. Anti-authority (don’t tell me!). This attitude is found in people who do not like anyone telling them what to do. In a sense they are saying no one can tell me 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 prerogative to question authority if you feel it is in error. The antidote for this attitude is: Follow the rules. They are usually right.
  2. Impulsivity (do something quickly!) is the attitude of 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. The antidote for this attitude is: Not so fast. Think first.
  3. 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. The antidote for this attitude is: It could happen to me.
  4. 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. While this pattern is thought to be a male characteristic, women are equally susceptible. The antidote for this attitude is: Taking chances is foolish.
  5. Resignation (what’s the use?). Pilots who think “what’s the use?” 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 that’s good luck. When things go badly, the pilot may feel that “someone is out to get me,” 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.” The antidote for this attitude is: I’m not helpless. I can make a difference.

Hazardous attitudes which contribute to poor pilot judgment can be effectively counteracted by redirecting that hazardous attitude so that appropriate action can be taken. Recognition of hazardous thoughts is the first step in neutralizing them in the ADM process. Pilots should become familiar with a means of counteracting hazardous attitudes with an appropriate antidote thought. When a pilot recognizes a thought as hazardous, the pilot should label that thought as hazardous, then correct that thought by stating the corresponding antidote.

If you hope to succeed at reducing stress associated with crisis management in the air or with your job, it is essential to begin by making a personal assessment of stress in all areas of your life. Good flight deck 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, you must condition yourself to relax and think rationally when stress appears. The following checklist outlines some thoughts on flight deck stress management:

  1. Avoid situations that distract you from flying the aircraft.
  2. Reduce your 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. Maintain proficiency in your aircraft; proficiency builds confidence. Familiarize yourself thoroughly with your aircraft, its systems, and emergency procedures.
  5. Know and respect your own personal limits.
  6. Do not let little mistakes bother you until they build into a big thing. Wait until after you land, then “debrief” and analyze past actions.
  7. If flying is adding to your stress, either stop flying or seek professional help to manage your stress within acceptable limits.

The DECIDE Model, comprised of a six-step process, is intended to provide the pilot with a logical way of approaching decision making. The six elements of the DECIDE Model represent a continuous loop decision process which can be used to assist a pilot in the decision making process when faced with a change in a situation that requires a judgment. This DECIDE Model is primarily focused on the intellectual component, but can have an impact on the motivational component of judgment as well. If a pilot practices the DECIDE Model in all decision making, its use can become very natural and could result in better decisions being made under all types of situations.

Fitness for Flight

As little as one ounce of liquor, one bottle of beer, or four ounces of wine can impair flying skills. The alcohol consumed in these drinks is detectable in the breath and blood for at least three hours. Alcohol renders a pilot susceptible to disorientation and hypoxia. Even after the body completely destroys a moderate amount of alcohol, a pilot can be severely impaired for many hours by hangover. There is simply no quick method for dissipating alcohol in the body or alleviating a hangover.

Pilots and passengers should allow sufficient time between scuba diving and flying, to rid the body of excess nitrogen absorbed during the dive. The recommended waiting time before flight to cabin pressure altitudes of 8,000 feet or less is at least 12 hours after diving which has not required controlled ascent (non-decompression diving), and at least 24 hours after diving which has required controlled ascent. The waiting time before flight to cabin pressure altitudes above 8,000 feet should be at least 24 hours after any scuba diving.

Supplemental Oxygen

The oxygen in the air causes approximately 21 percent of the total air pressure. At low altitudes, this partial pressure is sufficiently high to force oxygen into the blood through the lungs. As one goes up in altitude, the total air pressure becomes less, and above 28,000 feet, the pressure of the oxygen in the air is too low to force the oxygen into the blood. For the oxygen to enter the blood at high altitudes, the aircraft must be pressurized, or supplemental oxygen must be used.

Hypoxia is a state of oxygen deficiency in the body, sufficient to impair functions of the brain and other organs. Hypoxia from exposure to altitude is due only to the reduced barometric pressures encountered at altitude, for the concentration of oxygen in the atmosphere remains about 21 percent from the ground out to space. The most significant hazard of hypoxia at altitude is a crewmember engrossed in his/her flight duties may not notice the effects of hypoxia. These symptoms are typical of hypoxia:

  1. An increased breathing rate, headache, fatigue.
  2. Light-headed or dizzy sensations, listlessness.
  3. Tingling or warm sensations, sweating.
  4. Poor coordination, impairment of judgment.
  5. Loss of vision or reduced vision, sleepiness.
  6. Cyanosis (blue coloring of skin, fingernails, and lips).
  7. Behavior changes, feeling of well-being (euphoria).

Hyperventilation is a condition that can occur when there is a deficiency of carbon dioxide. This can be caused by an abnormal increase in the volume of air breathed in and out of the lungs and can occur subconsciously when a stressful situation is encountered in flight. It can also be caused by rapid or deep breathing while using oxygen. As hyperventilation blows off carbon dioxide that is needed by the body, a pilot can experience symptoms of light-headedness, suffocation, drowsiness, tingling in the extremities, and coolness, and react to them by breathing faster and deeper, causing even greater hyperventilation. The symptoms of hyperventilation subside within a few minutes after the rate and depth of breathing are consciously brought back under control. The buildup of carbon dioxide in the body can be hastened by controlled breathing, in and out, with a paper bag held over the nose and mouth.

Spatial Disorientation, Vertigo, and Visual Illusions

Inside the ear are located three hollow, semicircular tubes arranged at approximately right angles to each other. In each tube is a sensory organ consisting of small hairs that project into a gelatinous substance. When the head turns, speeds up, slows down, or stops turning, the sensory hairs in the tube in the axis of turning are temporarily deflected, due to the motion of the fluid lagging behind the motion of the tube wall. When these hairs are deflected, the pilot may experience spatial disorientation or vertigo. Action can be taken to prevent spatial disorientation and its potentially disastrous consequences:

  1. Always obtain preflight weather briefings.
  2. Do not continue flight into adverse weather conditions or into dusk or darkness unless proficient in the use of flight instruments.
  3. Ensure that when outside visual references are used, they are reliable, fixed points on the earth’s surface.
  4. Avoid sudden head movements, particularly during takeoffs, turns, and approaches to landing.
  5. Remember that illness, medication, alcohol, fatigue, sleep loss, and mild hypoxia are likely to increase susceptibility to spatial disorientation.
  6. Most importantly, become proficient in the use of flight instruments and rely upon them.

Rapid acceleration during takeoff can create the illusion of being in a nose-up attitude, and a disoriented pilot will push the aircraft into a nose-low, or dive attitude. Rapid deceleration caused by a quick reduction of the throttles can have the opposite effect, with the disoriented pilot pulling the aircraft into a nose-up, or stall attitude. An upsloping runway, upsloping terrain, or both, can create the illusion that the aircraft is at a higher altitude than it actually is. The pilot who does not recognize this illusion will fly a lower approach. A downsloping runway, downsloping approach terrain, or both can have the opposite effect.

Rain on the windscreen can create the illusion of greater height, and atmospheric haze causes the illusion of being a greater distance from the runway. The pilot who does not recognize these illusions will fly a lower approach.

In darkness, vision becomes more sensitive to light, a process called dark adaptation. Dark adaptation is impaired by exposure to cabin pressure altitudes above 5,000 feet, by carbon monoxide inhaled by smoking or from exhaust fumes, by deficiency in Vitamin A in the diet, and by prolonged exposure to bright sunlight.

Motion Sickness

Motion sickness is caused by continued stimulation of the tiny portion of the inner ear which controls the pilot’s sense of balance. Motion sickness, particularly among student pilots, is probably a result of combining anxiety, unfamiliarity, and the vibration or jogging received from the aircraft, and is usually overcome by experience. To overcome motion sickness, open up the air vents, loosen the clothing, use supplemental oxygen, and keep the eyes on a point outside the aircraft. Avoid unnecessary head movements, and cancel the flight and land as soon as possible.

Collision Avoidance

The eyes can focus only on a narrow viewing area, so effective scanning is accomplished with a series of short, regularly spaced eye movements that bring successive areas of the sky into the central visual field. Each movement should not exceed 10°, and each area should be observed for at least 1 second to enable detection.

An effective way of preventing a collision hazard in the traffic pattern is to enter the pattern at the correct position, midway of the downwind leg at an angle of 45°, at the correct traffic pattern altitude, and to continually scan the area for traffic.

The physical makeup of the eye is such that off-center viewing is most effective for night viewing. When you scan for other aircraft at night, do not look directly at the area you expect the aircraft to be flying, but rather scan slightly above or below the suspected area.

The FAA Near Mid-Air Collision Report indicates that 81% of the incidents occurred in clear skies and unrestricted visibility conditions, and 46% occurred over a VOR facility.

[10-2024]