Hazards Associated With Flying at Night Presented by Name Transport Canada, System Safety Transport Canada Transports Canada

Transport Canada Transports Canada Main Causes of Night Accidents VFR-into-IMC CFIT

Transport Canada Transports CanadaCARs CAR three mile visibility for night VFR CAR prohibits en route night VFR at less than 1000 ft above the highest obstacle along specific routes

Transport Canada Transports Canada The Eye

Transport Canada Transports Canada Factors that Affect our Night Vision Night vision Two blind spots Lack of colour vision Reduced acuity Reduced depth perception Night myopia Visual hypoxia Night blindness Effects of aging Carbon monoxide, alcohol, drugs, fatigue, smoking

Transport Canada Transports Canada Night Vision Process requires about 30 min Rods become adjusted to darkness Off-centre viewing important during night flights Smoking, carbon monoxide, hypoxia, certain drugs adversly affect night vision Avoid bright lights to preserve night vision Red light preserves night vision but severley distorts colours

Transport Canada Transports Canada Two Blind Spots Physiological blind spot Central blind Spot Use an off-centre scanning technique

Transport Canada Transports Canada Lack of Colour Vision Rod vision is unable to discriminate colours

Transport Canada Transports Canada Reduced Acuity Central vision blindness at night High rod-to-optic nerve fiber ratio reduces acuity

Transport Canada Transports Canada Reduced Depth Perception Rod vision and pupil dilation reduces depth perception

Transport Canada Transports Canada Night Myopia Shortsightedness occurs during dark focus Periodically change focus distance

Transport Canada Transports Canada Visual Hypoxia The retina of the eye is more sensitive to hypoxia than any part of our body One of the first symptoms of hypoxia is a decrease in night vision Effects most noticeable starting at 5000’ above ground level to which you are acclimated Smokers are much more susceptible to hypoxia due to the build-up of carbon monoxide in their blood

Transport Canada Transports Canada Night Blindness Functionally blind due to pigment deficiency in rods Night blindness induced within 60 days on diet lacking vitamin A

Transport Canada Transports Canada Effects of Aging Pupil size decreases Range of eye focus is reduced Visual acuity is reduced Colour discrimination becomes more difficult It takes longer to process visual information in general Sensitivity to glare increases Takes longer to read under dim light conditions

Transport Canada Transports Canada Night Illusions & Limitations Illusions Autokinesis (objects appear to shift) False reference (stars or lights near horizon) Venus and sirius (false aircraft) Night myopia (dilation, inability to focus) Somatogravic (acceleration with pitch) Limitations Night blind spot (rods & cones, stars, etc) Light to dark adaptation (2 hours)

Transport Canada Transports Canada Focused Scan Problems: Night Night blind spot (A.I.P. AIR 3.7) –centre portion of eye is blind at night Night Scan –look away from what you try to see –night vision is affected by altitude –drugs, alcohol, smoking and fatigue adversely affect night and day vision

Transport Canada Transports Canada Pre-Flight Planning Route Study Weather Conditions Equipment Alternate Plan

Transport Canada Transports Canada Ground Operations Taxi speed illusion Geographic disorientation Risk of collision

Transport Canada Transports Canada Take off and Climb Lining up Take off into the black-hole Somatogravic illusion

Transport Canada Transports CanadaCruise Ability to detect and monitor weather Terrain detection Geographic disoriention

VMC into IMC Conditions 178 Seconds

Transport Canada Transports Canada Approach and Landing Runway detection Black-hole approach Effects of runway slope Runway dimensions Atmospheric conditions Runway lighting

Transport Canada Transports Canada Diagram Black-hole Diagram 3 degree glidescope Arc of Constant Visual Angle Arc Radius

Transport Canada Transports Canada Be alert for the black-hole illusion if you observe these conditions An airport that is on the near side of a brightly lit city with few or no terrain features or lights between you and the airport An airport that is on the coast or lake shore An airport in a very sparsely settled areas

Transport Canada Transports Canada Fatigue Induces Human Error

Transport Canada Transports Canada Preventative Measures Recognize normal human visual limitations involved know what they are and circumstances they are most likely to occur Learn which airports are conducive to visual illusions at night and use the Canada Flight Supplement (CFS) for more information and restrictions during hours of darkness Use flight instruments for approaches especially those that provide glide path information (i.e., ILS, DME readouts and altimeter) Use airport aids to vision (i.e., VASIS, T-VASIS)

Transport Canada Transports Canada More Preventative Measures Avoid visual long straight-in approaches (overfly airport if necessary) For geographic disorientation use radio navigation and GPS if fitted Pay attention to alert devices (radio, altimeter, GPWS) Double check your own expectations and perceptions Ensure adequate sleep and nutrition