Be Aware of What Lurks in the Night

by Dean Chamberlain
Reprinted with permission from FAA Aviation News

Each year, FAA Aviation News looks at some aspect of winter-related flight operations as a way to remind pilots and maintenance technicians of some of the risks associated with this time of the year. In the past, we have discussed such topics as winter survival to preparing your aircraft for cold weather operations. This year, we are printing fatal accident data provided by Joe Mooney. Mooney, who works in the FAA's Office of Accident Investigation, did computer analyses of almost 30,000 NTSB records from the period 1995-2002. He based his search upon the listed probable causes. As he said, 'One accident can have more than one airplane involved, and one airplane can have more than one probable cause. So we are counting probable causes.'

Mooney provided data on accidents listing both light and dark probable causes. Then he compared them to see if 'dark' had any impact on the numbers. For the purpose of this report, dark includes dusk and night periods. Light includes day and dawn data. Accident data from Alaska and Hawaii are excluded. The data are pilot related. Someone had to be flying the aircraft or involved in the reported accident.

In the following data, the 'Difference Factor' column is calculated by dividing the dark accident percentage by the light accident percentage. The number is an indication of the apparent increased risk factor for dark operations involving that particular phase of flight.

As you can see, some 'Difference' factors are very minor. Some are more significant. Refueling, for instance, is nine times more likely to be a probable cause during dark than during light conditions. Because this is not a completely scientific study, we are only providing data to stimulate thought. But, based upon the following information, the fatal 'Difference Factor' numbers seem to show that phases of flight dealing with night landings, particularly those involving instrument flight procedures are more dangerous at night.

Based upon common wisdom, the following flight profile may explain why the numbers show that phases of night landings, particularly IFR landings, have a higher fatal probable cause rating. If you see yourself in this profile, you may want to reconsider how you fly or when you fly. You have worked all day. You have flown your own aircraft or your company's aircraft on a business trip that started before sunrise. You preflighted in the dark with cold outside air temperatures. You flew several hours to your meeting. You missed lunch and ate dinner out of the candy machine. After preflighting for your return trip in the dark, you are glad to get airborne. You spend another couple of hours airborne. You are tired and sleepy. As you prepare to fly the published instrument approach, you realize that instead of being alert and prepared to fly the procedure, you can hardly stay awake, let alone remain alert. If there is any type of wind or weather, you have just increased your risk of making a dumb mistake. Fatigue is a killer. Are you alert enough to make a safe landing? If you have ever found yourself in this situation, maybe the next time you see yourself in this accident profile, you might consider renting a hotel or motel room and spending the night. Based upon Mooney's work, you can reduce your odds of dying by several factors by waiting and departing during the daylight hours the next day. Or, if you don't want to spend the night, you could take another pilot along with you who could fly the return leg of your trip. You just need to make sure the pilot gets to rest or gets some sleep before the return trip. What you don't need is two very tired and sleepy pilots shooting an approach. You might even take an air carrier flight and leave the flying to them. Have a safe holiday period. Hope to see you next spring.