Human factors lesson
Human factors
- Spatial disorientation.
- Hypoxia.
- Hyperventilation.
- Motion sickness.
- Carbon Monoxide.
- Fatigue and stress.
- Dehydration.
- Alcohol and drugs.
- Scuba diving.
- Middle ear and sinus problems.
Spacial disorientation
- Brain receives messages that contradict what the body perceives.
- An incorrect mental image of your position in relation to what is actually happening to the airplane.
- 3 body sensory organs:
- Visual (eyes)
- vestibular (inner ear)
- Kinesthetic (nerves in the skin, joints and muscles).
- Conflicting information from the three areas may result in disorientation if not overcome.
- The best things to do is to be confident on your flight instruments, more than your feeling.
Vestibular Illusion
- The sensation of bank in the opposite direction:
- May occur when a banked attitude is entered too slowly to set the fluid in the vestibular system in motion but an abrupt correction is used to level the aircraft.
- Coriolis Illusion:
- An abrupt head movement in a prolonged constant-rate turn can create the illusion of rotation or movement in an entirely different axis
- Graveyard spin :
- Recovery from a spin and create the illusion of spinning in the opposite direction. The disoriented pilot returns the aircraft to its original spin.
- Graveyard spiral:
- Losing altitude in a constant rate turn creates the illusion of being in a descent with the wings level.The disoriented pilot will pull back on the controls, tightening the spiral and increasing loss of altitude.
pilot human facors
Hypoxia
- Hypoxia means « not enough oxygen ». It can severely impair the function of the brain and other organs. Judgment, perception and mental ability, amongst others are affected.
- Symptoms:
- Impaired judgment
- Euphoria.
- Blue fingernails and lips (Cyanosis).
- Headache.
- Visual impairment (tunnel vision, impaired night vision).
- Drowsiness .
- Dizzyness.
- Tingling and numbness in fingers and toes.
- Night vision starts becoming deteriorated already at 5000 ft cabin altitude.
- Descend to a lower altitude or using supplemental oxygen.
Hyperventilation
- Can occur as a reaction to:
- emotional stress.
- Fright.
- Pain…
- Symptoms:
- Are nearly the same as for hypoxia, but instead of cyanosis, and limp muscles, the person experiencing hyperventilation will have get a pale appearance, and possibly muscle spasms.
- Corrective actions:
- Control breathing rate. Try restoring CO2 levels by breathing in a paper bag.
- If unsure whether it’s hypoxia or hyperventilation – treat for hypoxia!
Motion Sickness
- Brain receiving conflicting messages about the state of the body.
- Common among passengers and some inexperienced pilots.
- If prone to motion sickness:
- Avoid turbulence.
- Open air vents
- Focus outside
- Avoid head movements.
- Start with short lessons, gradually longer.
- Medication is not recommended while piloting.
- Symptoms:
- General discomfort, nausea, dizziness, paleness, sweating, and vomiting.
Carbon Monoxide Poisoning
- Colorless and odorless gas produced by all internal combustion engines.
- Attaches itself to the hemoglobin in the blood about 200 times more easily than oxygen.
- Aircraft heater vents and defrost vents.
- Symptoms:
- Red lips, nails.
- Headaches.
- Blurred vision.
- Dizziness.
- Drowsiness, and/or loss of muscle power.
- Can result in death
- Inexpensive carbon monoxide detectors. Turns black when exposed.
- Corrective actions:
- Turn off the heater
- Open fresh air vents and windows.
- Use supplemental oxygen, if available.
- Tobacco smoke also causes carbon monoxide poisoning. Effects similar to flying at 8,000 feet.
Stress
- The body’s response to physical and psychological demands placed upon it.
- Release chemical hormones (such as adrenaline) into the blood.
- The blood sugar, heart rate, respiration, blood pressure, and perspiration (transpiration) all increase.
- Stressors:
- Physical stress (noise or vibration).
- Physiological stress (fatigue).
- Psychological stress.
- Acute (grave,aigu) stress (short term).
- Chronic stress (long term).
A certain amount of stress increases performance until it exceeds a specific level.
Fatigue
- Frequently associated with pilot error.
- Degradation of attention and concentration, impaired coordination, and decreased ability to communicate.
- Physical (sleep loss, exercise, or physical work) and mental fatigue (stress)
- Acute and chronic.
Dehydration
- Critical loss of water from the body.
- The first effect of dehydration is fatigue.
- Increased risk at hot summer days and/or high altitudes.
- If this fluid is not replaced, fatigue progresses dizziness, weakness, nausea, tingling of hands and feet, abdominal cramps, and extreme thirst.
Alcohol:
- Drinking and performance deterioration are closely linked.
- Alcohol drastically reduces the chances of completing a flight without incident.
- Even in small amounts alcohol can:
- Impair judgment.
- Decrease sense of responsibility.
- Affect coordination.
- Constrict visual field.
- Diminish memory.
- Reduce reasoning power.
- Lower attention span.
- With a hangover a pilot is still under the influence of alcohol.
- Alcohol interferes with the brain’s ability to utilize oxygen, producing a form of
- Don’t drink before a minimum of 8 hours pass between drinking alcohol and piloting an airplane. Good idea to be more restrictive than that.
Drugs
- Performance seriously degraded by both prescribed and over-the-counter medications, as well as by the medical condition they are taken.
- May impair judgment, memory, alertness, coordination, vision, and the ability to make calculations.
- If there is any doubt regarding the effects of any medication, consult an aviation medical examiner before flying.
SCUBA Diving
- Scuba diving then flying can lead to decompression sickness
- The bends can be experienced from as low as 8000 feet MSL.
- Minimum time before flying up to an actual altitude of 8000 feet:
- 12 hrs after dives which has not required a controlled ascent.
- 24 hrs after dives with controlled ascent.
- Flying above 8000 feet:
- Should be at least 24hrs after any scuba dive.
Blood Donations
- Because it takes several weeks for the blood circulation to return to normal after a blood donation, it’s recommended that pilot who are actively flying to refrain from volunteering as blood donors.
- It’s recommended that you should wait at least 48 hours.
Eating
- The stress of flying, or indeed of any activity, consume energy.
- This energy is derived from oxygen and from blood sugar.
- The pilot is unwise to fly for too long without eating.
- His blood sugar will be low (hypoglycemia), that is, his energy reserve will be low.
- Reaction will be sluggish (lente) and efficiency will be impaired.
- It’s good precaution to carry a nutritious snack on long flight.
Middle ear and sinus problems
- Differences in pressure due to climbs/descends between the outside air, and the air in the middle ear, or in the nasal sinuses may cause discomfort and pain. Worst during descent.
- Pressure equalized through Eustachian tube, which can be opened through chewing, yawning or valsalva maneuver.
- Can also affect teeth.
- During a cold, sinuses and the Eustachian tube may be swollen, equalizing will be harder.
- Symptoms:
- Pain and discomfort in sinuses, ears, teeth.
- Corrective actions:
- Attempt to equalize. Reduce rate of descent/climb.
Review questions
- What can be the causes of hyperventilation ?
- How long is the minimum time required after drinking alcohol before flying?
- What do you have to do to counteract the effect of spatial disorientation and illusion?
