Saying that night time visual flight operations are resulting in an increasing number of avoidable accidents, the National Transportation Safety Board said pilots need more training to increase altitude awareness and provide for better pre-flight planning for such operations if they are to avoid Controlled Flight Into Terrain (CFIT) accidents. “If you fly at night, especially in remote or unlit areas, consider whether a global positioning system-based terrain awareness unit would improve your safety of flight,” concluded the board.
Recent NTSB investigations have identified several accidents that involved CFIT by both instrument flight rules (IFR)-rated and visual flight rules (VFR) pilots operating under visual flight conditions at night in remote areas. In many of these cases, said the board, pilots were in contact with air traffic control (ATC) at the time of the accident and receiving radar service and all involved were unaware of the impending danger. .
The board cited six accidents nationwide which resulted in controlled flight into terrain and 16 fatalities. All involved the pilot being unaware of their altitude in relation to the surrounding mountainous terrain.
The NTSB also noted that proper flight planning would avoid such accidents, especially if pilots familiarizes themselves with the terrain and other topographic references throughout the flight path. The problem is most acute in remote areas, in overcast or moonless conditions, when darkness renders visual cues useless and may result in loss of horizon reference.
It recommended pilots follow IFR practices such as climbing on a known safe course until well above surrounding terrain, choosing a cruising altitude that provides terrain separation similar to IFR flights (2,000 feet above ground level in mountainous areas and 1,000 feet above the ground in other areas.)
It also said pilots should not depend on air traffic services to warn of terrain hazards since controllers may not recognize that a particular VFR aircraft is dangerously close to terrain. In addition, any heading issued along with instructions to “maintain VFR” should be double checked by the pilot to ensure it provides adequate terrain clearance.
“ATC radar software can provide limited prediction and warning of terrain hazards, but the warning system is configured to protect IFR flights and is normally suppressed for VFR aircraft,” said the board. “Controllers can activate the warning system for VFR flights upon pilot request, but it may produce numerous false alarms for aircraft operating below the minimum instrument altitude—especially in en route center airspace.” It also noted the FAA recommends supplemental oxygen above 5,000 feet to improve night vision.