Addressing Human Fatigue

What is the issue?
Airplanes, trains, trucks, buses, and ships are complex machines that require the full attention of the operator, maintenance person, and other individuals performing safety-critical functions. Consequently, the cognitive impairments to these individuals that result from fatigue due to insufficient or poor quality sleep are critical factors to consider in improving transportation safety. Whether driving a commercial vehicle, piloting a ship, or flying professionally for an airline, operators of transportation vehicles need to have sufficient off-duty time to obtain sufficient sleep. But duty schedules are only part of the equation. Even when an individual has enough time to get rest, medical conditions, living environment, and personal choices can affect the ability to obtain quality sleep.

Over the years, the NTSB has investigated many accidents, in all transportation modes, in which fatigue was cited as the probable cause or a contributing factor. Human fatigue is subtle; at any given point, the traveling public could be at risk because the professional pilots, vessel captains, motorcoach drivers, or truck drivers with whom, or near whom, they are travelling—or the individuals responsible for maintaining vehicles—do not realize until it is too late that they cannot safely complete their duties because of fatigue. To make matters worse, people frequently are not aware of, or may deny, ability impairments caused by fatigue. Just because a driver is not yawning or falling asleep does not necessarily mean that he or she is not fatigued.

What can be done . . .

Since its creation, the NTSB has issued more than 180 separate safety recommendations to address the problem of human fatigue in all modes of transportation. Continued research on the manifestations of fatigue will help in further identifying mechanisms that can counter, and ultimately eliminate, fatigue. Such research needs to recognize the unique aspects of fatigue associated with each mode of transportation, such as the effect of crossing multiple time zones on international flights or being required to work during periods of the day when circadian rhythms increase the risk of fatigue.

Fatigue-countering mechanisms must include science-based, data-driven hours-of-service limits, particularly for professional drivers, pilots, mechanics, and air traffic controllers. The medical oversight system must recognize the dangers of sleep-related medical impairments, such as obstructive sleep apnea, and incorporate mechanisms for identifying and treating affected individuals. Employers should also (1) establish science-based fatigue management systems that involve all parties (employees, management, interest groups) in developing environments to help identify the factors that cause fatigue, and (2) monitor operations to detect the presence of fatigue before it becomes a problem. Because “powering through” fatigue is simply not an acceptable option, fatigue management systems need to allow individuals to acknowledge fatigue without jeopardizing their employment.

Related Reports

Title: Evaluation of U.S. Department of Transportation Efforts in the 1990s to Address Operator Fatigue
NTSB Report Number: SR–99-01, adopted on 5/11/1999 [Summary | PDF Document]

Title: Aircraft Accident Report: In-Flight Fire and Impact With Terrain Valujet Airlines Flight 592 DC-9-32, N904VJ Everglades, Near Miami, Florida May 11, 1996
NTSB Report Number: AAR-97-06, adopted on 8/19/1997 [Summary | PDF Document]

Title: Aviation Accident Report: Weather Encounter and Subsequent Collision into Terrain, Bali Hai Helicopter Tours, Inc., Bell 206B, N16849, Kalaheo, Hawaii, September 24, 2004
NTSB Report Number: AAR-07-03, adopted on 2/13/2007 [Summary | PDF Document]

Title: Aircraft Accident Report: Attempted Takeoff From Wrong Runway Comair Flight 5191 Bombardier CL-600-2B19, N431CA Lexington, Kentucky August 27, 2006
NTSB Report Number: AAR-07-05, adopted on 7/26/2007 [Summary | PDF Document]

Title: Aircraft Accident Report: Runway Overrun During Landing Shuttle America, Inc. Doing Business as Delta Connection Flight 6448 Embraer ERJ-170, N862RW Cleveland, Ohio February 18, 2007
NTSB Report Number: AAR-08-01, adopted on 4/15/2008 [Summary | PDF Document]

Title: Highway Accident Report: Truck-Tractor Semitrailer Rear-End Collision Into Passenger Vehicles on Interstate 44, Near Miami, Oklahoma, June 26, 2009
NTSB Report Number: HAR-10-02, adopted on 9/28/2010 [Summary | PDF Document]

Title: Highway Accident Brief: Rear-End Chain Reaction Collision, Interstate 94 East, Near Chelsea, Michigan, July 16, 2004
NTSB Report Number: HAB-07-01, adopted on 12/4/2007 [Full Text | PDF Document]

Title: Highway Accident Report: Truck-Tractor Semitrailer Rollover and Motorcoach Collision With Overturned Truck Interstate Highway 94 Near Osseo, Wisconsin October 16, 2005
NTSB Report Number: HAR-08-02, adopted on 9/16/2008 [Summary | PDF Document]

Title: Collision of Two Canadian National/Illinois Central Railway Trains near Clarkston, Michigan, November 15, 2001
NTSB Report Number: RAR-02-04, adopted on 11/19/2002 [Summary | PDF Document]

Title: Railroad Accident Report: Collision Between Two Washington Metropolitan Area Transit Authority Trains at the Woodley Park-Zoo/Adams Morgan Station in Washington, D.C., November 3, 2004
NTSB Report Number: RAR-06-01, adopted on 3/23/2006 [Summary | PDF Document]

Title: Railroad Accident Report: Collision Between Two Massachusetts Bay Transportation Authority Green Line Trains, Newton, Massachusetts, May 28, 2008
NTSB Report Number: RAR-09-02, adopted on 7/14/2009 [Summary | PDF Document]

Title: Aircraft Accident Report: Collision with Trees and Crash Short of Runway, Corporate Airlines Flight 5966, British Aerospace BAE-J3201, N875JX, Kirksville, Missouri, October 19, 2004
NTSB Report Number: AAR-06-01, adopted on 1/24/2006 [Summary | PDF Document]
NTIS Report Number: PB2006-910401

Title: Aircraft Accident Report: Loss of Control on Approach, Colgan Air, Inc., Operating as Continental Connection Flight 3407, Bombardier DHC 8 400, N200WQ, Clarence Center, New York, February 12, 2009
NTSB Report Number: AAR-10-01, adopted on 2/2/2010 [Summary | PDF Document]
NTIS Report Number: PB2010-910401

Title: Aircraft Accident Report: Crash During Attempted Go-Around After Landing East Coast Jets Flight 81 Hawker Beechcraft Corporation 125-800A, N818MV Owatonna, Minnesota July 31, 2008
NTSB Report Number: AAR-11-01, adopted on 03/15/2011 [Summary | PDF Document]
NTIS Report Number: PB2011-910401

Title: Uncontrolled Collision with Terrain Air Transport International Douglas DC-8-63, N782AL Kansas City International Airport Kansas City, Missouri February 16, 1995
NTSB Report Number: AAR-95-06, adopted on 8/30/1995
NTIS Report Number: PB95-910406


More InformationFor more information on the safety recommendations in these reports that address this Most Wanted List issue area, see: