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Flashcards in Flight Physiology [Block 5] Deck (64)

What is the most important organ for pilots?




What are they?
What information do they provide the eye?
When is it best in use?
Where is it located and does it read color?

–Receptors concentrated in focal area
–Detail & Color Oriented
–Best in Light
–Cones – Color – Center of eye



What are they?
What information do they provide the eye?
When is it best in use?
Where is it located and does it read color?

–Receptors along periphery
–Not sensitive to color
–Detects movement and shapes
–Good for low light levels


Night Vision

•In low light, the cones will not perceive light

•Night Blind Spot
–Occurs in focal center where a large concentration of cones are located
–Looking 4-12 degrees to the side of object best way to see


How to avoid optical illusions? (8)

•How to Avoid
–Awareness of possible illusions
–Use instruments to verify perceptions
–Use autopilot
–Anticipate Illusions
–Use Visual Glideslope Indicators (VASA, PAPI, etc)
–Minimize Distractions
–Maintain proficiency
–Adjust lighting aids as necessary


Anatomy of the inner ear. (5)

More Info...

•Semicircular Canals
•Canals are filled with fluid
•Force move fluid
•Fluid stimulates hairs in canal
•Translates into movement in brain

•Canals insensitive to gradual changes of direction.
•Motion greater than 3 degrees per second is necessary to sense turning


Vestibular Illusions (6)

•Coriolis Illusion
•Graveyard Spin / Graveyard Spiral
•Somatogravic Illusion
•Inversion Illusion
•Elevator Illusion



What is it?
How does a pilot correct this?

•An abrupt correction from a bank that was entered too slowly to stimulate the motion sensing system creates the illusion of banking in the other direction.

•Pilot corrects by re-entering the banked attitude.


Coriolis Illusion

•An abrupt head movement in a prolonged constant rate turn that has ceased stimulating the motion sensing system can create the illusion of rotation or movement in an entirely different axis.


Graveyard Spin

Spin: A proper recovery from a spin that has ceased stimulating the motion sensing system can create the illusion of entering a spin in the other direction.

–Pilot re-enters original spin.


Graveyard Spiral:

Spiral: An observed loss of altitude during a coordinated constant rate turn that has ceased stimulating the motion sensing system can create the illusion of being in a descent with the wings level.
–Pilot pulls back on control yolk, causing the aircraft to descend at a faster rate.


Somatogravic Illusion

•A rapid acceleration during takeoff can create the illusion of being in a nose high attitude.
–The disoriented pilot may push the aircraft into a nose-low or dive attitude.

•Rapid deceleration can have the opposite effect


Inversion Illusion

•An abrupt change from climb to straight and level can create the illusion of tumbling backwards.

–Pilot may then push the aircraft into a nose-low attitude, further intensifying the illusion.


Elevator Illusion

•An abrupt upward vertical acceleration, usually by an updraft, can create the illusion of being in a climb.

•An abrupt downward vertical acceleration has the opposite effect.


Factors Effecting Illusions (6)

•Changes in acceleration & deceleration
–Forward acceleration causes a sensation of nose-up pitch

•Cloud Layers
•Low level flight over water
•Repeated transitions between VMC and IMC
•Unperceived changes in flight attitude
•No horizon/low visibility


Illusion Avoidance (7)

•Anticipate illusion situations
•Be able to recognize false sensations
•Develop instrument interpretation skills
•Be decisive about transitioning to instruments
•Avoid flying under stress
•Even experienced pilots encounter brand new illusions
•Stay ahead of the airplane


Atmospheric Considerations *test question*

–78% nitrogen, 21% oxygen at all altitudes
1% other

•Pressure decreases as altitude increases.
–However, the air composition remains unchanged


Physiological Zones

•Physiological Zone - SL to 10,000’
–We can adapt in this zone

•Physiological Deficient Zone - 10,000’ to 50,000’
–Majority of commercial flying
–Hypoxia due to altitude, as well as trapped and evolved gas problems, are concerns


Hypoxia Definition

•Lack of sufficient oxygen in the body to the point where function is impaired.
–Is due to a number of causes
–Can occur at any altitude

•Clearly is a pilot’s most important physiological concern.


Hypoxia Effects:

Influenced by?

•Significantly affects performance…can lead to incapacitation and death!
•Influenced by multiple factors
–Atmospheric considerations
–Respiration problems
–Blood donation
–Oxygen equipment design
… to name a few.


Four Types of Hypoxia *Test Question*



Hypoxic Hypoxia

What causes this?

How is it corrected?

•Partial pressure of oxygen is insufficient
–You cannot absorb adequate oxygen

•Correction: breathe a greater percentage of oxygen or oxygen under pressure
–Oxygen systems vary in what they deliver
–Descend to higher barometric pressures


Hypemic Hypoxia

What is the causes and effects?

•The oxygen-carrying capacity of the blood is reduced
–Carbon Monoxide interferes with oxygen binding to the blood

•Smoking, engine exhaust
–Sulfa drugs can have an effect also
–Blood donation also limits capability


Blood Donation

What is the effect of donation?

How long must you wait after blood transfusion?

How long must you wait after plasma donation?

•Symptoms of hypoxia at lower altitudes

•UND Policy
–72 hour wait after a blood donation or transfusion
–12 hour wait after a plasma donation


Stagnant Hypoxia

•Oxygen deficiency due to impaired circulation
–G forces from maneuvers
–Positive pressure breathing for extended periods
–Disease of the blood vessels


Histotoxic Hypoxia

•Tissue cells are poisoned and unable to use oxygen


Symptoms of Hypoxia

•Symptoms vary between individuals

•Symptoms are always the same for the individual

•Each symptom will ultimately lead to unconsciousness if untreated.

- Headache
- Euphoria
- Impaired Judgement
- Decreased Reaction Time
- Drowsiness
- Numbness
- Air Hunger
- Limp Muscles
- Blue around nails and lips (cyanosis)
- Tingling in Fingers or Toes


Effective Performance Time (EPT)


•Definition –
–Amount of time from loss of adequate oxygen partial pressure in which an individual can perform effectively

–Varies with altitude

–This is not a guarantee!


Corrective Actions for Hypoxia (3)

•Immediately use supplemental oxygen
–System on, Mask on, breathe normally

•Check operation of oxygen equipment
–Don’t wait for problems

•Make emergency descent if oxygen is not available


Oxygen Use Recommended

Why half at night?

•Per AIM
–Use above 10,000’ in the day
–Use above 5,000’ at night

*the eye demands more oxygen hence the lower altitude at night


FAR Part 91.211 – Supplemental Oxygen

12,500 or higher - Flight crew must use after 30 minutes

14,000 or higher - Flight crew must use for flight's duration

15,000 or higher - Flight crew must use and passengers must be provided oxygen.


Carbon Dioxide Management

What do carbon dioxide levels do?
What is normal breathing rate?
What will keep levels stable?

•Carbon Dioxide levels stimulate respiratory center of the brain, influencing how we breathe.

•Normal Breathing Rate is 12-16 breaths per minute

•Controlled breathing will keep our Carbon Dioxide levels stable.



What is it?
What does it cause?

•Respiration that is too rapid and/or deep for current physical activity
–results in a abnormal loss of carbon dioxide (CO2) from the blood.

–Emotional tension or stress
–Fear or anxiety
–Pressure breathing equipment


Hyperventilation: Symptoms (7)

•Hot & / or cold sensations
•Tingling of hand, legs, or feet
•Muscle spasms

*Hyperventilation symptoms are very similar to that of Hypoxia


Hyperventilation: Corrective Action

If symptoms remain?

•Correct for any potential of Hypoxia 1st.
•Check oxygen equipment for proper function.
•Breathe normally.
–If problem was hypoxia, symptoms disappear rapidly.

•If symptoms remain:
–breath slower
–breath into a bag
–talk aloud/sing


Carbon Monoxide Poisoning : Definition

•The inability of blood to carry oxygen because of an excess of Carbon Monoxide in the blood.

–Carbon Monoxide is absorbed much more rapidly by blood
–Carbon Monoxide prevents Oxygen absorption


Carbon Monoxide Poisoning: Causes (4)

•Leaky Heater
•Smoke from a Fire
•Pilot is more susceptible at higher altitudes


Carbon Monoxide Poisoning: Symptoms (6)

•Uneasy feeling rather than euphoria
•Mental confusion
•Effects can last for days


Carbon Monoxide Poisoning: Solutions (5)

Aim Recommendations: (2)

•Open fresh air vents
•Turn off heater
•Go on 100% oxygen
•Land as soon as practical
•Change detectors regularly

•AIM recommends;
–Get rid of carbon monoxide
–Land immediately - emergency descent


Decompression Sickness: Causes

•Symptoms caused by nitrogen gas coming out of solution in your body.

–Bubbles are formed as a result of Henry’s Law and a sudden loss of pressure.

–Bubbles can cause pain or disability due to hypoxia.

–Joint pain is the most common symptom.


Decompression Sickness:

Waiting Time

–Pressure loss, recent SCUBA diving
–Joint pain, chest pain, cyanosis, or any symptom of brain dysfunction

–100% oxygen, tight fitting mask
–Re-pressurize by descent or pressure chamber

•Waiting time
–At least 24 hours for all SCUBA dives.
–12 hours if flying below 8,000 MSL and performed a nondecompression dive.


Reactions To Stress:

•Heart rate quickens
•Motion sickness
•Stress, in moderation, can improve:
–Thinking speed
–Reaction time
–Situational awareness


Trapped Gas : Ear

What are symptoms?
How is it remedied?

•Ear - eardrum flexes causing pain
–Head colds & infections can block Eustachian tube (more common on descent)

–swallow, yawn, tense throat, valsalva, nasal inhalant
–Ascend until pain resolves, then use a slower descent


Trapped Gas: Sinus


•Pressure occurs the same way as in the ears
–Pain is felt on sides of nose, upper jaw, above eyes
–Occurs more commonly on descent

–Valsalva maneuver
–Nasal sprays can be used only to help with descent…DO NOT USE PRIOR TO FLIGHT!
•Use as a get-me-down drug


Trapped Gas: Toothache


–imperfect fillings
–inadequately filled root canals

–visit to dentist


Trapped Gas - Gastrointestinal


–Abdominal Pain
–Difficulty breathing
–Lowers blood pressure, leading to shock
–Severe pain above 25,000’

–belching, passing flatus, descending


Dehydration: Mild Dehydration Effects

•Mild dehydration can have the following effects:
–Decreased coordination
–Impairment of higher functions
•Situation awareness


Heat Exhaustion Symptoms:

Fatigue, exhaustion, nausea, and light headedness


Dehydration: Water Loss

Respiration ?

•Water loss
–Respiration: 1-2 liters a day normally
•Up to 6 liters a day in cold, dry air
–Sweat: 1-2 liters a day normally
•Heavy exertion: 1-3 liters per hour
–Bathroom break: 1-2 liters per day


Dehydration: Loss Per Day Average

4 liters

Active individuals can dehydrate in 15 minutes in hostile environments.


Avoiding Dehydration

How to •Minimize fluid loss? (3)


•Minimize fluid loss
–Pace your activities
–Protect from the heat

–Drink fluids proactively not based upon thirst
–Water is best
•Avoid carbonated and caffeine drinks


Types of Stress (2)

•Acute (short term)
•Chronic (long term)


Things That Degrade Performance: (4)



Reactions to Stress: (4)

Stress in moderation can improve: (4)

•Heart rate quickens
•Motion sickness
•Stress, in moderation, can improve:
–Thinking speed
–Reaction time
–Situational awareness


Physical Stress Definition

•Conditions associated with the environment, such as temperature and humidity extremes, noise, vibration, and lack of oxygen


Psychological Stress:

Social or Emotional Factors?
Physical Conditions?

•Social or emotional factors, such as a death in the family, a divorce, a sick child, or a demotion at work. This type of stress may also be related to mental workload, such as analyzing a problem, navigating an aircraft, or making decisions

•Physical conditions, such as fatigue, lack of physical fitness, sleep loss, missed meals (leading to low blood sugar levels), and illness


Alcohol :

Far Regulations?
How long must you wait from last drink?
What is BAC limit?
Can you fly under effects?

How fast can two ounces of alcohol absorb into blood stream?

How long does it take for two ounces to metabolize out of system?

–8 hours bottle to throttle (12 UND)
–.04% blood alcohol content - less than 1/2 of automobile standard
–No effect of alcohol prior to the flight….
•A hangover is an effect seen with



•2 mg of nicotine per cigarette

•Given orally 2.5 mg causes nausea, 50-60 causes death

•Tolerances develop

•CO is 2.5% of volume of cigarette smoke



•Aspirin, Ibuprofen, and Tylenol
•Cold and cough medication
•Motion sickness medication

•Aspirin, Ibuprofen, and Tylenol
–safe to take it and fly
•Cold and cough medication
–Most are not approved for flight
–Are you too sick to fly?
•Motion sickness medication
–Not approved


Prescription Drugs:

•What is being treated may cause you to be grounded

Who is the authority on prescription drugs and flying?

•What is being treated may cause you to be grounded
–Ear infections
–Sore throats
•AME is authority on prescription drugs and flying

•If you need medication – are you too sick to fly?



What are the two types ?
How do they differ?
What does Fatigue do?

•Acute fatigue – caused by intense mental or physical activity at a single task.

•Chronic fatigue – caused over time by such factors as lack of sleep, jet lag, and stress. Can be cured by rest but may take a few days.

–Degrades attention and concentration required for ADM
–Focus attention on physical activity
–Lowers your attention to detail


Short Vs. Long Runway

- Short may seem higher on approach, longer may seem lower on approach.


Spatial Systems

•Our “position sense” lies within the nerves of muscles, skin, & joints.
–“Seat of the Pants” expression originates here

•Body is easily fooled when flying solely by the forces felt.


What is the pilot's most important physiological concern?

Lack of sufficient oxygen - Hypoxia