Night Operations Flashcards
Name the two distinct types of light-sensitive cells located in the retina of the eye.
Rods and cones
What is the function of the cones and where are they located in the eye?
The cones are used to detect color, detail and far-away objects and are located in the center of the retina at the back of the eye. They are less sensitive to light, require higher levels of intensity to become active, and are most useful in the daylight hours.
What is the function of the rods and where are they located in the eye?
Rods are located in the back of the eye or retina. The rods function when something is seen out of the corner of the eye or peripheral vision. They detect objects, particularly those that are moving, but do not give detail or color - only shades of gray. Both the cones and the rods are used for vision during daylight. In the absence of normal light, the process of night vision is placed almost entirely on the rods.
What is the average time it takes for the rods and cones to become adapted to darkness?
Approximately 5 to 10 minutes for the cones to become adjusted to darkness. About 30 minutes for the rods to become adjusted to darkness.
What should the pilot do to accommodate changing light conditions?
The pilot should allow enough time for the eyes to become adapted to the low light levels and then should avoid exposure to bright light which could cause temporary blindness.
Give several examples of illusions related to ground lighting conditions.
1) On a clear night, distant stationary lights can be mistaken for stars or other aircraft. Certain geometrical patterns of ground lights, such as a freeway, runway, approach, or even lights on a moving train can cause confusion. Dark nights tend to eliminate reference to a visual horizon.
2) A black-hole approach occurs when the landing is made from over water or non-lighted terrain where the runway lights are the only source of light. Without peripheral visual cues to help, pilots will have trouble orientating themselves relative to Earth. The runway can seem out of position (downsloping or upsloping) and in the worse case, results in landing short of the runway.
3) Night landings can be complicated by the difficulty of judging distance and the possibility of confusing approach and runway lights. For example, when a double row of approach lights joins the boundary lights of the runway, there can be confusion where the approach lights terminate and runway lights begin. Under certain conditions, approach lights can make the aircraft seem higher in a turn to final, than when its wings are level.
4) If you stare at a stationary light too long, it will start to look like it is moving with you. To fix this, look away from the light for a brief period of time.
During takeoff you suddenly feel as if the aircraft is in an excessively high nose-up attitude. What type of illusion is this?
Somatogravic illusion. A rapid acceleration during takeoff can create the illusion of being in a nose-up attitude. A pilot disoriented by a somatogravic illusion may respond by pushing the aircraft into a nose low or dive attitude.
When approaching a well-lit runway surrounded by a dark area with little or no features, what illusion should a pilot be alert for?
Featureless terrain illusion - An absence of ground features, as when landing over water, darkened areas, and terrain made featureless by snow, can create the illusion that the aircraft is at a higher altitude than it actually is. The pilot who does not recognize this illusion will fly a lower approach.
What should the pilot do to maintain good eyesight?
Good eyesight depends upon physical condition. Fatigue, colds, vitamin deficiency, alcohol, stimulants, smoking, or medication can seriously impair vision.
What can the pilot do to improve the effectiveness of vision at night?
1) Adapt the eyes to darkness prior to flight and keep them adapted. About 30 minutes is needed to adjust after exposure to a bright light.
2) If oxygen is available, use it during night flying. Significant deterioration in night vision can occur at cabin altitudes as low as 5,000 feet.
3) Close one eye when exposed to bright light to help avoid the blinding effect.
4) Do not wear sunglasses after sunset.
5) Move the eyes more slowly than in daylight.
6) Blink the eyes if they become blurred.
7) Concentrate on seeing objects.
8) Force the eyes to view off center.
9) Maintain good physical condition.
10) Avoid smoking, drinking, and using drugs that may be harmful.
What equipment should the pilot have for night flight operations?
At least one reliable flashlight is recommended as standard equipment on all night flights. A reliable incandescent or light-emitting diode (LED) flashlight able to produce white/red light and blue for chart reading is preferable. Include a second flashlight (such as a head-mounted type) as a backup. The white light is used while performing the preflight visual inspection and the red light is used when performing cockpit operations. A spare set of batteries is also recommended.
What other items should the pilot have on board for night flights?
Aeronautical charts are essential for night cross-country flight and, if the intended course is near the edge of the chart, the adjacent chart should also be available. It is also recommended to have a spare set of batteries for the flashlight readily available. Organize equipment and charts and place them within easy reach prior to taxiing.
Explain the arrangement and interpretation of the position lights on an aircraft.
A red light is positioned on the left wingtip, a green light on the right wingtip, and a white light on the tail. If both a red and green light of another aircraft are observed, and the red light is on the left and the green to the right, the airplane is flying in the same direction. Care must be taken not to overtake the other aircraft and to maintain clearance. If red were on the right and green to the left, the airplane could be on a collision course.
Position lights are required to be on during what period of time?
From sunset to sunrise
When an aircraft is operated in, or in close proximity to, a night operations area, what is required of an aircraft?
The aircraft must:
1) Be clearly illuminated
2) Have lighted position lights
3) Be in an area which is marked by obstruction lights
Are aircraft anticollision lights required to be on during night flight operations?
Yes; however, the anticollision lights need not be lighted when the PIC determines that, because of operating conditions, it would be in the interest of safety to turn the lights off.
