Numerous studies have concluded that significant sleep deprivation is equivalent to operating while under the influence of alcohol. The British Medical Journal concluded that "after 17–19 hours without sleep, performance on some tests was equivalent or worse than that at a BAC of 0.05%. Response speeds were up to 50% slower for some tests and accuracy measures were significantly poorer than at this level of alcohol. After longer periods without sleep, (up to 28 hours) performance reached levels equivalent to the maximum alcohol dose given to subjects (BAC of 0.10%)."

It's illegal to drive a car in the U.S. with a blood alcohol content at or above 0.08 to 0.10%.

The role of fatigue was mentioned during an NTSB hearing on the Colgan accident. Board chairman Deborah Hersman argued that several issues, including the crew's sleep deficits and the time of day the accident took place, were factors and said that fatigue was present and should be counted as a contributing factor to the crew's performance.

But the view of board member and former USAirways pilot Robert Sumwalt prevailed. He concluded that fatigue wasn't a factor in the accident. It didn't stop them from detailing the role it played in Colgan 3407 (PDF LINK)

So if nicotine is found to cause some cancer, but its role in a person's life expectancy cannot be determined, should we rule it out as a possible factor in a lung cancer death?

The British Medical Journal study concluded that fatigue does affect performance, finding that, "getting less than 6 hours a night can affect coordination, reaction time and judgment" and poses "a very serious risk" to drivers.

It was precisely this reaction time and judgment that are to blame in the Colgan accident. I'm sure if you had asked Captain Renslow about the proper response in a stall, he would have been able to recite the steps verbatim. But that night, he was operating in a fog caused by a lack of quality sleep for the past 36 hours.

And the copilot, Rebecca Shaw, after commuting across the country all night before starting her day, misinterpreted the stall for possible icing conditions that she thought was affecting the tail and so she retracted the flaps during the recovery, exacerbating an already difficult recovery.

Most pilots expected sleep deprivation to play the leading role in the Colgan 3407 accident. The industry has averaged nearly an accident a year for the past twenty years with fatigue listed as a contributing factor. Could this have been the first case where a lack of sleep was actually considered the cause of a crash?

If a lack of sleep can affect affect coordination, reaction time and judgment, how conclusive does fatigue have to be, to be considered a cause in an accident that lists improper reactions and judgement as the main factors?

This time the NTSB isn't even attaching fatigue as a 'contributing factor' in the Colgan accident, even though they went on to say in the report:

All pilots, including those who commute to their home base of operations, have a personal responsibility to wisely manage their off-duty time and effectively use available rest periods so that they can arrive for work fit for duty; the accident pilots did not do so by using an inappropriate facility during their last rest period before the accident flight.

There is no doubt in my mind that, if a BAC of, say, .08% were discovered in the pilots' blood that the NTSB would list this as the cause of the accident and close the case.

I've always been a proponent of the NTSB. They look at human factor trends and educate us on ways to avoid them. As a fresh 20 year-old pilot, I even defended the local NTSB office in a KOMO4 TV news report when their numbers were reduced.


The NTSB has done as much as the FAA to ensure safe flying for the masses. I don't understand why they've been reluctant to properly address the role of fatigue in a number of accident reports.

Perhaps it's because airlines are terrified at the thought of reducing the 16-hour duty day further, which could lead to the recall of a few pilots at each company. Airlines point to a policy that allows a pilot to call in 'fatigued' if they don't feel rested. But we don't allow pilots to self diagnose when they're too drunk to fly-we simply have limits on how much time must pass before they can fly.

So the fatigue policy, while helpful, isn't the only way to ensure pilots are well rested on their next flight. Furthermore, Colgan unilaterally put new restrictions on the use of fatigue calls by its pilots.

But the FAA was confident enough that fatigue was a causal factor in the Colgan Dash 8 accident to start acting before the final NTSB report has been issued. They are working on new limits that will reduce the duty day for pilots, which includes both flight time and the time sitting around in airports between flights.

To appease the industry, the FAA may have to agree to a slight increase in flight time limits-the number of hours a pilot is allowed to be in the air in a day-currently 8 hours for a two-pilot crew-to secure improvements to the current 16 hour duty day for pilots.

I applaud the FAA's decision to take on this cause after their previous 1995 attempt failed. At least the FAA seems to recognize that, for most pilots, it's not the number of hours flown in a day, but it's the amount of time on duty, and during what time of day a pilot is on duty that affects our safety.

Because there's no way we'll solve the fatigue issue if we continue to deny it leads to accidents.



Do you have a question about something related to the pointy end of an airplane? Ask Kent and maybe he'll use it for the next Plane Answer's Plane Answers. Check out his other blog, Cockpit Chronicles and travel along with him at work. Twitter @veryjr

Gallery: Ten pilots you don't want in your cockpit