total darkness. A takeoff at night is usually an “altitude over  airspeed” maneuver, meaning a pilot most likely performs  a nearly maximum performance takeoff. This improves the  chances for obstacle clearance and enhances safety. In order to provide a higher margin of safety, it is  recommended that a cruising altitude somewhat higher than  normal be selected. There are three reasons for this. First,  a higher altitude gives more clearance between obstacles,  especially those that are difficult to see at night, such as high- tension wires and unlighted towers. Second, in the event of  an engine failure, there is more time to set up for a landing  and the greater gliding distance gives more options for a safe  landing. Third, radio reception is improved, particularly if  using radio aids for navigation. During preflight planning, when possible, it is recommended  that a route of flight be selected that is within reach of an  airport, or any safe landing site. It is also recommended  that pilots fly as close as possible to a populated or lighted  area, such as a highway or town. Not only does this offer  more options in the event of an emergency, but also makes  navigation a lot easier. A course comprised of a series of  slight zigzags to stay close to suitable landing sites and  well-lit areas, only adds a little more time and distance to an  otherwise straight course. In the event of a forced landing at night, use the same  procedure recommended for day time emergency landings.  If available, turn on the landing light during the final descent  to help in avoiding obstacles along the approach path. Because the quantity and quality of outside visual references  are greatly reduced, a pilot tends to focus on a single point  or instrument, making him or her less aware of the other  traffic around. Make a special effort to devote enough time  to scan for traffic. As discussed previously in this chapter,  effective scanning is accomplished with a series of short,  regularly spaced eye movements that bring successive  areas of the sky into the central visual field. Contrary to  the 30-degree scan used to view the ground in the case of  scanning for other aircraft, each movement in this case  should not exceed 10 degrees, and each area should be  observed for at least 1 second to enable detection. If the  pilot detects a dimly lit object in a certain direction, the  pilot should not look directly at the object, but scan the area  adjacent to it, called off-center viewing. This will decrease  the chances of fixating on the light and allow focusing more  on the objects (e.g., tower, aircraft, ground lights). Short  stops of a few seconds in duration in each scan will help to  detect the light and its movement. A pilot can determine  Various surface features and atmospheric conditions  encountered in night landing can create illusions of incorrect  height above and distance from the runway threshold.  Landing errors from these illusions can be prevented by  anticipating them during approaches, conducting an aerial  visual inspection of unfamiliar airports before landing, using  electronic glideslope or VASI systems when available, and  maintaining optimum proficiency in landing procedures.  Although the landing light is a helpful aid when making  night approaches, there is an inherent disadvantage. The  portion of the landing area illuminated by the landing light  seems higher than the dark area surrounding it. This effect  can cause a pilot to terminate the approach at an altitude that  is too high, which may result in a vortex ring state condition  and a hard landing. Another pilot tendency during night flight is to focus too  much on the landing area and not pay enough attention to  airspeed. If too much airspeed is lost, a vortex ring state  condition may result. Maintain the proper attitude during  the approach, and ensure that you keep some forward  airspeed and movement until close to the ground. Outside  visual references for airspeed and rate of closure may not be  available, especially when landing in an unlit area, so pay  special attention to the airspeed indicator. Carefully controlled studies have revealed that pilots have a  tendency to make lower approaches at night than during the  day. This is potentially dangerous as there is a greater chance  of hitting an obstacle, such as an overhead wire or fence, that is  difficult to see. It is good practice to make steeper approaches at  night, increasing the probability of clearing obstacles. Monitor  altitude and rate of descent using the altimeter. Night approaches and landings do have some advantages over  daytime approaches, as the air is generally smoother, and the  disruptive effects of turbulence and excessive crosswinds are  often absent. However, there are a few special considerations  and techniques that apply to approaches at night. For  example, when landing at night, especially at an unfamiliar  airport, make the approach to a lighted runway and then use  the taxiways to avoid unlighted obstructions or equipment. another aircraft’s direction of flight by interpreting the  position and anticollision lights, as previously described.  When scanning, pilots should also remember to move their  heads, not just their eyes. Ground obstructions can cover  a considerable amount of sky, and the area can easily be  uncovered by a small head movement. Approach and Landing En Route Procedures Collision Avoidance at Night Illusions Leading to Landing Errors 12-9