Tired?

May 1, 2006

AOPA Air Safety Foundation Executive Director Bruce Landsberg is a 5,000-hour-plus ATP.

The great football coach Vince Lombardi said, "Fatigue makes cowards of us all." The phrase also is attributed to Gen. George Patton, but regardless of which great man said it first, pilots should take it to heart. There's been a long-running battle between airline management, pilots, the FAA, and the NTSB as to when a pilot becomes too tired to be safe. In personal flight operations we answer only to ourselves, but I believe fatigue plays a much bigger role than official accident reports indicate.

You can't see fatigue, although the eyes may be bloodshot or the posture stooped. You can't smell it, and there are no traces in the body after a fatal accident like with drugs, alcohol, or carbon monoxide. Yet we've all experienced fatigue while flying or driving. We might think of ourselves as machines, but the reality is that our skill and energy levels vary from day to day.

There are volumes of sleep books, articles, and research on circadian rhythm. It's the natural body clock that drives our need for sleep. A French scientist in the 1700s discovered that sleep and wakefulness patterns generally follow the 24-hour rotation of the Earth and are affected by light and temperature. The body relies on multiple cues to stay on track — sleep, social interactions, and meals all influence the internal clock. We all have different sleep needs and these needs change based on age, health, and activity. This is complex stuff and plays a significant role in safe flight.

Under FAR Part 91, for personal flight there are no formal restrictions — fly as long as you like and nobody will ask any questions unless there is a violation, incident, or accident. For flight instructors the rules are slightly more limiting. FAR 61.195 requires that CFIs give no more than eight hours of flight training in any consecutive 24-hour period. Going back to my time as a full-time CFI, an eight-hour flight day meant at least a 12-hour airport day if you gave any meaningful pre- and postflight briefings. I also recall being just a "bit less effective" in those last few hours.

Moving to air-taxi rules and unscheduled flights with one- or two-pilot crews — a profile that might more closely match the typical general aviation transportation flight — the hours can get really long. FAR 135.267, with six paragraphs and 11 subparagraphs, is something only a lawyer could love. You can read it for yourself, but it says that under certain conditions a pilot could be completely legal and still be a mental marshmallow. Anecdotal discussion and observations with charter crewmembers reveal that many of them are chronically tired, and it's no coincidence that many FBOs have sleep rooms. That's better than nothing, but perhaps not much.

Anyone who has ever tried to sleep under the wrong conditions — and we all have — knows that even though you are technically "resting," meaningful sleep doesn't come. Flying eastbound across five or six time zones in airline coach class to Europe does not bring fond memories. A typical flight leaves in the early evening and arrives in the early morning, with the planet neatly subtracting about two-thirds of your normal rest period. It's somewhat noisy, coach seats are designed to meet the needs of airline accountants and not passengers, the temperature is too hot or too cold, the lighting is less than optimal, invariably there are other passengers who are wound up on adrenaline, alcohol, or who knows what, and your circadian rhythm is royally disrupted.

The business traveler or tourist is a zombie for a few days, but his mistakes aren't measured in blood as a pilot's might be. Flight crews struggle to get it together, and 18 hours later they're working back across the pond at less than optimal efficiency. This happens thousands of times a month with airlines all over the world, and yet while pilots and passengers are dragging, the safety record is still quite good. In the airline world, however, there are multiple safety checks and balances. Is it right? That's a subject for another article. On the really long hauls the aircraft now include crew sleep areas and extra pilots, which is not a bad way to go.

Getting back to GA, we see a disproportionate number of accidents relative to the number of flight hours on the back side of the clock. If you normally awaken at 6 a.m. you know how it feels to get up at 3 a.m. Like a cold engine, it takes awhile to get going and there may be a few stoppages before everything is running smoothly. Freight and cargo pilots, particularly in single-pilot operations, periodically will crash on an approach in the early morning despite being "used" to a night schedule. Daytime sleep frequently isn't very good for the reasons mentioned above.

Here is a classic fatigue accident. A college student who was enrolled at a Part 141 school in the Midwest embarked on a long cross-country training flight. On July 7, 2004, he departed Grand Forks, North Dakota, at 6:15 p.m. and flew a Piper Warrior to Airlake Airport in Minnesota, on the first leg of his cross-country flight arriving at 8:30. The second leg of the flight concluded at Minneapolis' Crystal Airport at 9:30. The aircraft was refueled while the pilot met a friend and went to a restaurant for dinner. As an aside, he had a high-carbohydrate meal that, in all probability, raised his blood sugar two hours later to help induce sleep. He departed Minneapolis at 11:55 p.m. and climbed to 4,500 feet msl; he contacted flight service about 12:30 a.m. to open his flight plan back to Grand Forks.

The pilot reported his first VFR checkpoint, missed the second checkpoint, but continued on course using VOR and GPS navigation. He visually identified Detroit Lakes, Minnesota, but did not remember anything else until he opened his eyes in a cornfield, having been thrown clear of the wreckage. Radar data indicated that the Warrior's altitude varied from 4,200 to 4,800 feet msl and the aircraft was on course until 1:26 a.m. It then entered a gradual left spiral, completing six turns before radar contact was lost around 1:33 a.m. at about 1,900 feet msl (less than 400 feet agl).

The aircraft was destroyed and no preimpact malfunctions could be found. There was fuel in both tanks, the engine was running at the time of impact, and there were no deficiencies in the muffler or exhaust system to indicate possible carbon monoxide poisoning.

The pilot held a private pilot certificate with just more than 90 hours of flight time. He had eight hours in the previous 30 days and total night-flight experience also was at about eight hours. Why was he flying so late? To complete night-flying training requirements; summer civil twilight does not end until 10 p.m. in the North Country.

The pilot's 72-hour history prior to the accident is educational. On July 6 he woke up at 8 a.m. and went to bed at 2 a.m. on July 7. His alarm clock went off at 6 a.m. after only four hours of sleep, but he continued to sleep until about 7:30 a.m. He reported for class at 10 a.m. and ate at around 3 p.m. He went to the airport at 3:30 p.m., completed cross-country flight planning, and reviewed the flight plan with his flight instructor. The flight was delayed about an hour and 20 minutes when his aircraft would not start and a replacement had to be found.

As with many of us, busy lives and other activities interfere with flying. College flight students have every bit as demanding a schedule as the professional pilots that they hope to become. With class schedules, flight lessons, study periods, and part-time jobs to pay the tuition, fatigue is one of the great concerns of many university flight safety directors. The university implemented a duty-time policy for students, and every aviation safety class has a briefing on this accident to warn of the dangers of flight when tired. And like the real world, there is a constant balancing between conflicting needs. It's not smart to ignore the physical aspects of piloting and that includes health, food, water, and rest. Guess Mother was right again. If you doubt it go look at the accident statistics.