Version 1.0, 15 May 2011 Stage 1, Module 5 Copyright © 2011 Ted Dudley.
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Transcript of Version 1.0, 15 May 2011 Stage 1, Module 5 Copyright © 2011 Ted Dudley.
Version 1.0, 15 May 2011
Stage 1, Module 5
Copyright © 2011 Ted Dudley
Objectives
For the student to understand the factors which affect the physiology of flight
To become familiar with the regulations which govern the student and private pilot, and general aviation flight
Fitness to Fly
HEY!You can get pretty seriously killed doing this
stuff!Particularly if you’re not both physically and
mentally prepared to fly every time you step towards the airplane
You must always answer the question “Am I fit to fly today?”
Not just in training: every time for the rest of your life
Physical Fitness to Fly
After your medical is issued, the only person that checks your fitness to fly is you. Take into account: Illnesses/injuries Medications Cold/upper respiratory infection Use of corrective lenses Food poisoning Alcohol/tobacco use Fatigue Blood donation
Mental Fitness to Fly
Nobody ever checks for this except youIf you don’t feel like flying today, don’t fly!
Not mentally prepared for a training ride Emotionally in turmoil
Grief Anger Fear Problems with loved ones Problems at work
Medical Checks
Annual checkup, though not required for Class III, is a good idea Your doc may find things that can be dealt with before
the FAA gets involved Many things are easily treated if found early
Medication
Many common meds are not approved for use when enjoying the privileges of your certificate For example, most over the counter cold medications
It’s your responsibility to know what they areYou probably don’t know, so ask your Aviation
Medical ExaminerThey’re not approved because they could
affect your ability to fly safely
Upper Respiratory Problems
Tissue swelling associated with a cold or upper respiratory infection can block: Eustachian tubes Sinuses
Eustachian Tube Blockage
Eustachian tubes equalize air pressure on either side of eardrum and you experience much pressure changing in flight
Yawning naturally opens Eustachian tubesNormally, you can force pressure equalization with a
valsalva maneuver: Pinch the nostrils shut Close the mouth and lips Blow slowly and gently in the mouth and nose
Blocked Eustachian tubes reduce hearing sensitivity, can cause ear pain
Badly blocked Eustachian tubes could result in ruptured eardrums
Sinuses are cavities in the skull that contain airNormally connected to nasal passages for
equalization of air pressureBlocked sinuses can be excruciatingly painful, as
air trapped in the sinus expands and increases pressure on tissues
Occurs most frequently during descentSlow descent rates can reduce the associated
painBadly blocked sinus can lead to structural
damage of the sinus
Sinus Block
Corrective Lenses
Your Medical Certificate may require you to fly with corrective lenses
Even if not, if glasses/contacts help you, wear them
You can’t see and avoid if you can’t seeAlways a good idea to have a spare or backup
with you
Food Poisoning
Can easily debilitate you from 30 minutes to six hours after eating
Probably don’t want to try the raw oysters just before flying
Alcohol
Don’t be a knucklehead! Alcohol always interferes with your ability to operate an aircraft
14 CFR 91.17 says no person may operate or attempt to operate an aircraft: within 8 hours of having consumed alcohol while under the influence of alcohol with a blood alcohol content of 0.04% or greater while using any drug that adversely affects safety
It’s not hard to have a blood alcohol content higher than 0.04% even after 8 hours since consumption
Best if there is no alcohol left in you when you fly
Smoking
Tobacco smoke causes mild carbon monoxide (CO) poisoning
Smoking at sea level can raise the CO concentration in the blood and result in physiological effects similar to flying at 8,000 feet
Besides hypoxia, tobacco causes diseases and physiological debilitation that are medically disqualifying for pilots
Fatigue/Sleep Deprivation
Fatigue causes Degradation of attention and concentration Impaired coordination Decreased ability to communicate
…none of which are helpful to your ability to make effective decisions
Acute fatigue can be prevented by proper diet and adequate rest and sleep
If fatigue occurs in the flight deck, no amount of training or experience can overcome the detrimental effects
If suffering from acute fatigue, stay on the ground
Blood Donation
Giving blood causes a type of hypoxiaFAA policy: An airman who has donated
200cc or more for plasmapheresis or blood donation should not fly for at least 24 hours
Low Temperatures
We’re flying a single engine airplane – someday, that engine won’t work any more
If that happens while we’re in it, we’ll land somewhere, maybe far from any airport or road
Plan to spend a night in that caseAlways dress for survival in that eventuality
Think how disappointed you’ll be when you survive the landing, then freeze to death
Respiration and Flying
Increased altitudeHypoxiaCarbon monoxide poisoningHyperventilationDecompression sickness
Increased Altitude
Atmospheric pressure decreases with altitudeAs the airplane ascends during flight, the
percentage of each gas in the atmosphere remains the same, but there are fewer molecules available
At very high altitudes, low pressure can cause decompression problems
Hypoxia
Means “not enough oxygen”You need a certain amount of oxygen to
function normallyThere are several kinds of hypoxia, but the
one you’re most likely to encounter in small airplanes is hypoxic hypoxia As the airplane ascends during flight there are fewer
molecules available at the pressure required for them to pass between the membranes in the respiratory system
This results in not enough oxygen for you to function normally
Hypoxia Symptoms
Symptoms vary with individuals, but may include Cyanosis (blue fingernails and lips) Headache Decreased reaction time Impaired judgment Euphoria Visual impairment Lightheaded or dizzy sensation Tingling in fingers and toes Numbness
Hypoxia Cure
Descend!Use oxygen if available
Carbon Monoxide Poisoning
Exhaust gases contain large amounts of carbon monoxide (CO), which is odorless and colorless
Carbon monoxide is deadly and quick actingThere is a CO detector in the cabinIf the spot turns dark…
Cabin heat – closed Ventilate the cockpit as much as
possible
Hyperventilation
Excessive rate and depth of respiration leading to abnormal loss of carbon dioxide (CO2) from the blood If you breathe very rapidly (usually as a response to
emotional stress), you expel more CO2 through your lungs than usual
Your nervous system interprets low blood CO2 as a signal to automatically breathe faster
Breathing can still be consciously controlled
Hyperventilation Symptoms
Abnormally rapid breathingOther symptoms similar to hypoxia:
Visual impairment Lightheaded or dizzy sensation Tingling sensations Hot and cold sensations Muscle spasms Unconsciousness
Hyperventilation Cure
Consciously slow breathing to a normal rate Breathing normally will raise blood CO2 level
Breathe into a paper bag Rebreathing air from the bag will raise blood CO2
levelTalking out loud
You can’t breathe fast and talk at the same time
Decompression Sickness (DCS)
At very high altitudes (and low pressure), gases dissolved in body tissues and fluids come out of solution and form bubbles Much like taking the cap off a soda bottle
These bubbles can cause moderate to severe neurological damage and death
Generally not a problem at the altitudes we’ll fly in trainingFlying after scuba diving makes DCS more likely
Waiting time before going to flight altitudes of up to 8,000 feet: At least 12 hours after diving that does not require controlled ascent
(nondecompression stop diving) At least 24 hours after diving that does require controlled ascent
(decompression stop diving) Waiting time before going to flight altitudes above 8,000 feet should be at
least 24 hours after any scuba dive
Orientation and Balance
The body uses three integrated systems working together to ascertain orientation and movement in space Visual system—eyes, which sense position based on
what is seen Somatosensory system—nerves in the skin, muscles,
and joints, which, along with hearing, sense position based on gravity, feeling, and sound
Vestibular system—organs found in the inner ear that sense position by the way we are balanced
Visual System
During flight in visual meteorological conditions (VMC), the eyes are the major orientation source
The visual system almost always prevails over false sensations from other sensory systems
When visual cues are removed, as they are in instrument meteorological conditions (IMC), false sensations can cause a pilot to quickly become disoriented
Sensing Acceleration
The somatosensory system sends signals from the skin, joints, and muscles to the brain that are interpreted in relation to the Earth’s gravitational pull It tells you “which way is up”
“Seat of the pants” flying is largely dependent upon these signals
In conjunction with visual and vestibular clues, these sensations can be fairly reliable
However, the body cannot distinguish between acceleration forces due to gravity and those resulting from maneuvering the aircraft
This can lead to sensory illusions and false impressions of an aircraft’s orientation and movement
Inner Ear Balance Mechanism
The vestibular system in the inner ear allows the pilot to sense movement and determine orientation in the surrounding environment
In both inner ears, three semicircular canals are positioned at approximate right angles to each other
Each canal is filled with fluid and has a section full of fine hairs
Acceleration of the inner ear in any direction causes the tiny hairs to deflect, which in turn stimulates nerve impulses, sending messages to the brain to interpret motion
Vestibular System
Vestibular System
Under normal flight conditions, when there is a visual reference to the horizon and ground, the sensory system in the inner ear helps to identify the pitch, roll, and yaw movements of the aircraft
When visual contact with the horizon is lost, the vestibular system becomes unreliable
Without visual references outside the aircraft, there are many situations in which combinations of normal motions and forces create convincing illusions that are difficult to overcome
Sensing Angular Acceleration
Motion Sickness
Motion sickness, or airsickness, is caused by the brain receiving conflicting messages about the state of the body
You may experience motion sickness during initial flights, but it generally goes away within the first few lessons
Lots of excellent pilots have experienced motion sickness during initial training
Motion Sickness
If symptoms of motion sickness are experienced during a lesson: Open fresh air vents Focus on objects outside the airplane Avoid unnecessary head movements
Although medications like Dramamine can prevent airsickness in passengers, they are not recommended while flying since they can cause drowsiness and other problems
Vertigo
A condition where you mistakenly think you’re accelerating in a particular direction
One form of spatial disorientationCan be experienced as a feeling of dizziness
and imbalance that can create or increase illusions
Spatial Disorientation
The lack of orientation with regard to the position, attitude, or movement of the airplane in space
Your orientation systems work very well for walking around; not so good for flying, particularly when flying in a cloud without benefit of your visual system
Without visual clues, your somatosensory and vestibular systems will lie to you every time
Without visual clues, you must disregard what your body tells you, and use aircraft instruments for orientation
Sensory Illusions
All these illusions require loss of visual clues. If you can see the horizon, you won’t experience them: The leans Coriolis illusion Graveyard spiral Somatogravic illusion Inversion illusion Elevator illusion
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.
An abrupt correction of this attitude sets 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 in the perceived vertical plane until this illusion subsides
Coriolis Illusion
Occurs when a 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 flight deck, may set the fluid moving and create the illusion of turning or accelerating on an entirely different axis
The disoriented pilot may maneuver the aircraft into a dangerous attitude in an attempt to correct
Coriolis Illusion
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 flight deck—if something is dropped, retrieve it with minimal head movement and be alert for the coriolis illusion
Graveyard Spiral
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
Graveyard Spiral
Because an 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
Graveyard Spiral
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
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
Let’s see your certificate
Title 14, Code of Federal Regs
Title 14, Aeronautics and SpaceCommonly referred to as Federal Aviation
Regulations, or FARs, which they used to be called
Divided into Parts, many of which are of interest to pilots Part 1, Definitions and Abbreviations Part 61, Certification: Pilots, Flight Instructors, and
Ground Instructors Part 91, General Operating and Flight Rules
NTSB 830
NSTB is National Transportation Safety Board
Now found in 49 CFR Part 830Notification and Reporting of Aircraft
Accidents or Incidents and Overdue Aircraft, and Preservation of Aircraft Wreckage, Mail, Cargo, and Records
Defines accidents and incidentsGives requirements regarding whom to
report to and deadlines for reporting accidents and incidents