文本教程加拿习ff-151hf lp4vision,visual scanning hearing noise etc

1、1MEDICAL HUMAN FACTORSFF-101Vision, Visual Scanning, Hearing, Noise, Vibration, Orientation, Disorientation, Positive and Negative “G”2VISUAL ACUITYRETINA a projection screen, transfers the image to the Cones. From this over a million nerve cells meet and e the optic nerve.CONES are photosensor cell

2、s in the back of the eye. Gives sharp vision and are responsive in good light.RODS as you move progressively away from the center of the eye the photsensors are replaced by Rods. They give less focused images and are responsive in very low light.3Vision, Perception And ReactionThe most perfect eye w

3、ill not detect other aircraft unless the pilot is alert.Identifying a target requires:Picking it up.Locking on.RecognitionA reaction time of several seconds is needed before the information can be translated into action.4Empty Field of MyopiaOccurs when the field of vision is empty, as at high altit

4、ude or at night.The focus of the eye drifts to approximately 2 meters.This can be corrected by looking at a distant object such as a cloud, ground feature or a wing-tip of the aircraft. 5HEARINGThe Parts Of The Ear:Outer Ear funnels sound waves to the ear drum, a thin, semi-elastic membrane elastic

5、membrane causing to vibrate.Middle Ear, the vibrations are conducted across this section by three impedance matching bones to the inner ear.Inner Ear, the size of a pea, is set in dense bone and contains the organs of balance and Cochlea.It is here wear the vibrations are converted into nerve impuls

6、es and are transferred to the brain/ 6Hearing LossCauses of Hearing Loss:Wax build up in the outer ear.In pilots and divers, damage to the middle ear sometimes is caused by pressure changes.Inflammation or infection of the middle ear can scar and thicken the ear drum.Being exposed to a loud noise wh

7、ich may damage the inner ear.Continuous exposure to a constant noise at a lower dB level.7Effects of NoiseNoise increases task errors, causes stress, is very distracting, and may be the significant cause of fatigue.Noise ProtectionCan be plished by wearing:Ear plugs.HeadsetsHelmets with liquid-fille

8、d seals.8VibrationAny form of motion that repeatedly alternates in direction is a Vibration.Vibrations affect mobile parts of the body such as the head, shoulder girdle, limbs and also large organs such as the liver.Vibration in flight can arise from the environment or from the aircraft engines.9Ori

9、entation and DisorientationWe rely on three systems for most of our orientation:Kinesthetic sensors.Vision.Vestibular organs in the inner ear.Kinesthetic Illusions“Flying by the seat of the pants” describes the position sense used in flight on most days.A wise pilot knows that when kinesthetic sensa

10、tions and the instruments disagree, the instruments are right.10BIRDIN THETHE HAND11Visual IllusionsVision is separated in to 2 divisions:Central or focused vision is used for object recognition.Peripheral vision is a main source of spatial orientation.White-out White-out occurs when a fresh layer o

11、f snow merges with a white sky. This causes the horizon to be indistinguishable and make depth perception impossible.12False HorizonsTypes of False Horizons:Lining up with sloping cloud tops between layers is not mon.While flying over sparsely settled areas ground lights and stars may e confused.A d

12、imly lit, straight road.13Vectional IllusionsIllusions of false movement are common and hard to ignore.Types of Vectional Illusions:1.Angular Vection occurs when there is a rotation in the field of peripheral vision2.Autokinesis a light appears to move, but the movement is actually caused by the eye

13、s losing fixation, drifting away and jumping back to the target.14Vestibular IllusionsThese are the most complex and dangerous illusions:1.Linear Accelerations2.Angular Accelerations.3.Graveyard Spiral4.Coreolis Effect.5.The Leans.15Motion SicknessAir sickness is a form of motion sickness and all ar

14、e susceptible.Caused by:A conflict between what the eye sees and what the motion receptors report.Anxiety and/or fear prolong motion sickness.Passengers are more likely to experience this condition than pilots/drivers.Those prone to motion sickness should not eat or drink immediately prior to a flig

15、ht.16Positive and Negative “G”What is “G”?Rate of change of velocity and so represents both a force and direction.The Effects of “G”“G” Tolerance varies greatly with the individual.“G” Tolerance is increased by good muscle tone and decreased by obesity, ill health, low blood pressure, pregnancy etc.

16、17Positive “G”A 150lb. Pilot exposed to +2G will effectively weigh 300lbs.Positive “G” causes the blood to drain from the head to the feet and cause:Initially the periphery vision will e dim and colorless “GREY OUT”.As the forces increase the vision is eventually lost “BLACK OUT”.The end result is Stagnant Hypoxia.18NEGATIVE “G”This type of “G” is poorly tolerated, blood rushes from the feet to the head.Blood pressure in the eyes and the brain is increased which causes “RED OUT”.A Negative “G” in exces