The function of the ciliary muscles in the eye is to alter the shape of the lens to allow the eye to focus on objects at various distances move the eye from left to right in the socket move the eyelids to produce blinking change the size of the pupil to vary the amount of light entering the eye.
When light passes through the lens it is brought to focus at the back of the eyeball on the retina optic nerve cornea
iris.
The two different types of light sensitive elements on the retina are classified as rods which are sensitive to colour and cones which work best in dim light cones which are sensitive to colour and rods which work best in dim light
rods and cones both of which respond equally to all lighting conditions rods and cones both of which are responsible for colour vision.
The blind spot is the area of the lens which is screened by the iris the black spot in the centre of the coloured section of the eye at the junction of the optic nerve and the retina an area on the cornea which does not respond to light.
If a pilot whose eyes have fully adapted to darkness is exposed to a bright flash of light, the time required for
dark adaptation to be re-established is most likely to be 3 minutes 5 minutes 15 minutes 30 minutes
.
Prolonged exposure to bright glare such as beach sand or snow can cause a significant reduction in night vision
for up to 12 hours one day one week one month.
Empty Field Myopia is the tendency of the ciliary muscle to relax when there are no close objects in the field of
view. This causes the eye to take up a focal length of approximately one to two metres six metres infinity twenty-five metres.
The maximum distance at which a healthy eye in good lighting and contrast could identify a circle one metre in
diameter is approximately one kilometre five kilometres
2 nautical miles five hundred metres.
The perception of colour is a function of the cones on the retina and is diminished in dim ambient lighting rods on the retina and is diminished in dim ambient lighting cones on the retina and is diminished in bright lighting conditions rods on the retina and is diminished in bright lighting conditions
.
In level flight, a collision risk exists if a converging aircraft viewed from your cockpit appears to be on the horizon and maintaining a constant position in your windscreen below the horizon and moving closer to the centre of your windscreen on the horizon and moving away from the centre of your windscreen on the horizon
.
The most effective way to scan the sky for other aircraft during level flight is to move the head in a continuous arc from side to side keep the head still and move the eyes continuously from side to side do not look anywhere but straight ahead unless you detect movement move the head about 10° or 15° at a time, pausing after each movement to allow the peripheral
vision to detect any movement
.
Night vision is enhanced by looking slightly to one side of the object you wish to view fixing your gaze directly on the object you wish to view ensuring that the cockpit remains brightly illuminated drinking lots of carrot juice.
After being exposed to normal lighting, dark adaptation [night vision] returns after a recovery period of about 30 minutes 1 hour 2 minutes 10 minutes.
For a pilot who is exposed to a high glare environment while on the ground [beach sand or snow], which of the
following would help to enhance night vision? do not read small print within one hour of flying wear good quality sunglasses during the day avoid using contact lenses keep the cockpit lighting as bright as possible until just before takeoff.
Night vision is extremely sensitive to any reduction of oxygen supply to the retina. The lowest level at which
night vision starts to be affected is
2000 ft 4000 ft 10 000 ft 15 000 ft.
The most effective method for scanning the sky for other aircraft is to move the head to scan small sectors allowing
the eyes to stop regularly throughout the scan while focusing on the horizon this statement is true this statement is false.
What is the limit of resolution for a person with good vision at a distance of 2 nautical miles? a circle with a diameter of .5 metres
a circle with a diameter of 1 metre a circle with a diameter of 2 metres a circle with a diameter of 3 metres.
Which of the following eye problems is a natural consequence of ageing? astigmatism myopia hyperopia presbyopia.
In which of the following situations would a scratched and dirty windscreen have the most detrimental effect on
the pilot's forward vision during the day? flying beneath a thick overcast of cloud flying above a thick overcast of cloud flying away from the setting sun landing into a low sun
.
Heavy rain may have the effect of making objects viewed through the windscreen appear further away than they actually are closer than they actually are larger than they actually are brighter than they actually are.
To avoid the possibility of the eyes taking up a resting focus position when flying in conditions without visual
texture, it is recommended to stare at the horizon periodically look at an external aircraft fixture such as a wingtip blink regularly fixate at infinity.
To avoid an aircraft moving into the visual blind spot in a pilot's field of view, it is recommended to
move the head as well as the eyes
move the eyes only close one eye when scanning not rely on see and avoid for separation .
While night flying, the pilot of a passenger aircraft is exposed to the momentary flash of a match in the
cabin. Full dark re-adaption will take not more than 5 minutes about 30 minutes 10 to 15 minutes at least an hour
.
Flicker vertigo is a condition which may occur during flight in a helicopter due to the strobe effect of light through
the rotor disc. It may lead to a feeling of excessive speed disorientation an over alert state of mind a state of total relaxation
.
Night vision may be assisted by avoiding dark rooms during the day avoiding the use of sunglasses during the day avoiding bright light during the day and wearing sunglasses avoiding the use of a hat when out in bright sunshine.
Night vision is enhanced by looking slightly off centre. This is due to the concentration of rods in the foveal periphery the concentration of cones in the foveal periphery the concentration of cones in the retinal periphery the concentration of rods in the retinal periphery .
When scanning the horizon for traffic, the technique a pilot should use is to move the head smoothly with pauses and many brief pauses between eye movements move the head smoothly and continuously and many long pauses between eye movements move the head smoothly with pauses with many long pauses between eye movements
.
When visually scanning, the saccade/rest cycle duration is 1 second 0. 1 seconds 0.3 seconds 0. 7 seconds .
The anatomical part of the eye which focuses the visual image onto the retina is the - fovea iris lens maculus lutea .
The eye adapts to changes in ambient light intensity by adjusting the iris to change the shape of the pupil and making chemical changes in the retina the shape of the lens with the ciliary muscle the cornea and the shape of the lens the position of the rods and cones.
Light is focused onto the retina by the action of the lens only the cornea only the cornea and the leans the cornea and the iris .
The brain perceives the body's orientation in space by processing information from the eyes [visual cues] processing information from the inner ear [vestibular cues] processing information from the skeletal muscles and joints [postural cues] combining and comparing visual, vestibular and postural cues.
In sensing the orientation of the body in space, the brain assigns the highest priority to information coming from
the eyes the inner ear the middle ear the proprioceptive system.
Which of the following is the most likely cause of disorientation? a change in the information coming from the inner ear a conflict or ambiguity in the information coming from visual, vestibular and postural cues poor lighting reducing the amount of visual information received a rapid transition from level flight to a steep climb.
In the absence of reliable visual information, which of the following states of motion would be most difficult to
differentiate? a steep turn and a rapid deceleration in level flight a rapid acceleration in level flight and a transition from level flight to a dive a rapid acceleration in level flight and a transition from level flight to a climb
a rapid deceleration in level flight and a transition from level flight to a climb.
The most effective way to deal with an episode of disorientation in flight is to keep a constant look-out for glimpses of the natural horizon outside rely absolutely on the aircraft's instruments keep the control column central and maintain a constant power disregard the instrument indications and fly by 'feel' until it passes.
'The leans' is a state of disorientation which occurs when the rate of onset of the initial bank angle is above the threshold of perception, but the rate of
the pilot's correction to a level attitude is below that threshold the rate of onset of the initial bank angle is below the threshold of perception, and the rate of
the pilot's correction to a level attitude is also below that threshold the rate of onset of the initial bank angle is below the threshold of perception, but the rate of
the pilot's correction to a level attitude is above that threshold the rate of onset of the initial bank angle is above the threshold of perception, and the rate of
the pilot's correction to a level attitude is also above that threshold.
The Coriolis illusion can produce an unpleasant tumbling sensation. It is most likely to occur when the head is turned rapidly from left to right during visual flight the head is bowed forward rapidly during instrument flight a rapid deceleration occurs during level flight an aircraft which has been in a shallow turn for some time rolls back to level flight.
The somatogravic illusion [falsely identifying a level acceleration as a steep climb], is most likely to be encountered
during a go-around in a high performance aircraft when flying visually just after the transition from instrument to visual flight during an approach to a poorly lit runway on a dark night during and just after take-off in a high performance aircraft on a dark night
.
When an aircraft is performing a prolonged shallow turn during instrument flight, a common illusion is a sensation of being banked in the opposite direction when the wings are rolled back to the
level attitude a sensation of remaining banked in the turn when the wings are rolled back to the level
attitude a sensation of climbing when the wings are rolled back to the level attitude a sensation of diving when the wings are rolled back to the level attitude.
If a pilot who experiences the somatogravic illusion reacts to the associated false sensation, there would be a
danger of the aircraft being flown back into the ground after take-off. the statement above is false
the statement above is true.
Which of the following is true regarding perspective? if two aircraft are in the field of view, the one which appears larger is always closest to the
observer if two aircraft are in the field of view, the one which appears closer to the horizon is always
further away any point which is on the horizon must be at the same height as the observer if two aircraft in the field of view are at the same height, they will also appear to be the same
distance above or below the horizon.
One illusion which may be experienced on a dark night approach to a very wide runway which is remote from
street or town lighting is the aircraft appears to be higher than it actually is during the flare prior to touchdown the aircraft appears to be lower than it actually is during the flare prior to touchdown the aircraft appears to be travelling faster than it actually is during the landing roll the aircraft appears to be higher than it actually is during the approach.
One illusion which may be experienced on a dark night approach to a narrow runway which is remote from street
or town lighting is the aircraft appears to be higher than it actually is during the flare prior to touchdown the aircraft appears to be lower than it actually is during the flare prior to touchdown the aircraft appears to be travelling slower than it actually is during the landing roll the aircraft appears to be lower than it actually is during the approach.
You are making an approach by day into a runway where the terrain slopes up from the threshold of intended
landing. The most likely misjudgment during this approach would be an overestimate of your height above the runway threshold an underestimate of your height above the runway threshold an underestimate of your speed during the approach an overestimate of the length of the runway.
During a constant angular acceleration in the yawing plane, the hair-like cells in the semicircular canals of the
inner ear will be deflected in the same direction as the turn deflected in the opposite direction as the turn in an upright position waving to and from.
Which of the following organs mediates the sense of balance? eustachian tube the eardrum the semicircular canals the cochlea.
The effects of vertigo may be reduced or eliminated by rapidly scanning between the instruments and features on the ground looking for the horizon when visibility is poor concentrating on the artificial horizon only scanning all of the instruments and ignoring any sensations that are not confirmed by
instrument indications.
The susceptibility to disorientation is increased if the pilot is suffering from anxiety, stress or mental fatigue this statement is false this statement is true.
The proprioceptive system generates sensation from the semicircular canals the otolith the skeletal muscles, joints and tendons the skin.
The autokinetic illusion is responsible for an isolated distant light appearing to move when stared at for a period of time brightly lit towns appearing closer than they actually are on a dark night a pilot rounding out too high when landing on a wide runway on a dark night a pilot confusing acceleration on take-off for a steep climb.
When viewed from the cockpit of an aircraft, a small town which is approximately five nautical miles away will
appear to be closer than it actually is on a dark night closer than it actually is in daylight further away than it actually is on a dark night further away than it actually is in daylight .
The somatogravic illusion causes the pilot to think that deceleration in a descent is level flight deceleration in level flight is a climb acceleration in a climb is level flight acceleration in level flight is a climb.
The effects of vertigo may be reduced or eliminated by rapidly scanning between instruments and external visual features looking only outside in conditions of poor visibility scanning all instruments only fixating only on one instrument.
The "black hole" phenomena on take-off refers to the inability of light to escape beyond the event horizon the somatogravic illusion autokinesis the place where odd socks go.
A pilot's susceptibility to visual illusions during approaches will be increased by fatigue the amount and nature of their flying experience good night adaptation the presence of good glideslope guidance .
Disorientation is likely to occur as a result of flying on instruments only, if you accidentally enter a cloud while in flight avoiding looking at instruments for reference if you accidentally enter a cloud while in flight avoiding fast head movements when no external horizon is visible only looking outside the cockpit on a sunny day with no cloud
.
A pilot experiencing spatial disorientation in IMC should avoid head and eye movements scan all instruments fixate on one instrumen concentrate on outside visual cues .
On approach to land on a runway at night with an overwater approach a pilot is likely to perceive that the
runway is further away than it really is and that the approach is too low resulting in an overshoot further away than it really is and that the approach is too high causing an undershoot
closer than it really is and that the approach is too low resulting in an overshoot closer than it really is and that the approach is too high causing an undershoot.
The most important cue used by a pilot in judging height is aircraft attitude runway length
texture flow on the ground ground illumination intensity from landing light.
A disoriented pilot should vigorously seek external visual cues avoid head movements combine flight instrument indications with external visual clues roll the aircraft into a rate one level turn and maintain the turn until re-oriented.
A pilot is most likely to fly an approach which is too low when the approach is made the runway is wider than usual the runway lights are brighter than usual the runway slopes down from the aiming point the runway is shorter than usual.
Disorientation is a conditions which exists when there is not enough visual information available to the brain there is insufficient information available from visual, vestibular and proprioceptive cues the body is subjected to rapid accelerations there is conflict of information from visual, vestibular and proprioceptive cues.
Information from the eyes, ears combine with proprioceptive information to give the body a sense of equilibrium situational awareness navigation position vertigo.
During take-off on a dark night it is important during the initial climb out to seek as many visual cues as possible from outside the cockpit keep checking the instrument indications with outside information concentrate only on the instruments to maintain the aircraft's attitude fly by 'feel' as much as possible.
When maintaining the correct approach path to land on a runway which is shorter than usual you may think you are low and therefore tend to overshoot think you are high and therefore tend to overshoot think you are low and therefore tend to undershoot think you are high and therefore tend to undershoot.
Which of the following will always be accompanied by an increase in positive G load? increased IAS in a dive any manoeuvre which requires extra power any manoeuvre which requires the pilot to pull back on the control column any manoeuvre in which the aircraft's nose is above the horizon.
Which of the following will always be accompanied by an increase in positive G load? increased IAS in a dive any manoeuvre which requires extra power any manoeuvre which requires the pilot to pull back on the control column any manoeuvre in which the aircraft's nose is above the horizon
.
Which of the following is an effect of a sustained high G load? a slowing of the heart beat a decreased flow of oxygenated blood to the brain an increased flow of oxygenated blood to the brain an irregular heart beat.
Very high transient [short-duration] G loads can be tolerated with little effect because the brain can continue to function for a few seconds on the residual oxygen which was present
before the onset of the G load the heart responds immediately to the onset of high G loads by pumping faster high G load forces freshly oxygenated blood to the brain the brain can continue to function without oxygen until the increased heart rate compensates.
In which of the following situations would a normal healthy person be most likely to experience loss of consciousness
[G-LOC]? eight G sustained for two seconds three G sustained for five seconds seven G sustained for seven seconds two G sustained for fifteen seconds.
Which of the following would not increase a pilot's tolerance to high G loads? adopting a more reclined seating position tensing of the stomach muscles just before the onset of and during the G load maintaining a high level of physical fitness adopting a more erect seating position
.
Which of the following is an effect of a sustained negative G load? a slowing of the heart beat a decreased flow of oxygenated blood to the brain pooling of blood in the abdomen and legs
an irregular heart beat.
Which of the following transitions of G loads would be most likely to produce G-LOC? from a high positive to high negative G load from a high negative to high positive G load from a low positive to high positive G load from a low negative to high negative G load.
At about which sustained G load will a healthy person be likely to begin to experience grey out? 1.5 G 2.5 G 3.5 G 4.5 G.
At about which sustained G load will a healthy person be likely to begin to experience black out? 7 G 5 G 3.5 G 2.5 G.
Which of the following would most likely lead to carbon monoxide contamination of the cockpit atmosphere? excessive use of carburettor heat an electrical short circuit flying low in a very thick smoke haze a leak in the engine exhaust system.
Which of the following is not a symptom of carbon monoxide poisoning? headache and fatigue a feeling of euphoria discomfort in breathing impairment of vision and mental confusion.
When using cabin heat in light single-engined aircraft it should be remembered that there is a possibility that carbon monoxide can be introduced directly into the cockpit through
exhaust leaks in the heat exchanger
the frequent use of cabin heat can increase the risk of fire the use of full cabin heat during take-off can degrade the aircraft's take-off performance cabin heat should be used in cruising flight only, and never in climbs or descents.
Which of the following would be suitable treatment for a person suffering from carbon monoxide poisoning? administer oxygen give plenty of water give a sleeping pill have them re-breathe their exhaled breath from a bag placed over the nose and mouth.
Carbon monoxide is dangerous because it displaces oxygen from the blood's red cells it stings the eyes and seriously impairs vision
it is highly acidic and attacks the lining of the lungs it displaces oxygen from the lungs causing suffocation.
One design feature which would improve the tolerance to high positive G loads is a five-point, full aerobatic harness a more reclined seating position an upright seating position a joystick rather than a control column.
The action which should be taken in the event of a person suffering from carbon monoxide poisoning is to provide oxygen give water lie the patient down and keep them warm have the patient re-breathe inside a paper bag.
A symptom of carbon monoxide (CO) poisoning is a feeling of well being with no pain or discomfort tingling of the bodies extremities blue colouring of the fingers and toes warm and sluggish feelings with a tendency to headaches.
The most likely result of exposure to negative G forces is G induced loss of consciousness (GLOC)
sagging facial features burst blood vessels in the eyes black out.
If you suspect that you are suffering from carbon monoxide poisoning during flight you should open all available air vents and use oxygen. close all air vents and use cabin heat slow down your breathing rate. hold your breath.
Items of clothing that offer good resistance to flame contain a high percentage of synthetic frabics wool cotton plastic.
The accepted limit for negative G for a healthy person is considered to be -1G -2G -3G -4G.
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