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Human Factors in Accident Investigations

11 investigationsFrom the official reportsUpdated Sep 2026

Human factors is the study of how people perform in their working environment: their abilities and limitations, and how equipment, procedures and organisations support or undermine them. Most accident reports identify human performance as a factor, but modern investigations do not stop at "pilot error".

Following James Reason's model of organisational accidents, often drawn as the Swiss cheese model, they look for the conditions that made an error likely and for the defences that failed to catch it: training, procedures, cockpit design, rostering, supervision, and the safety culture of the operator and of the regulator. ICAO Annex 13 states that the sole objective of an investigation is the prevention of accidents and incidents, and that it is not its purpose to apportion blame or liability, which is why reports speak of findings and contributing factors rather than guilt. The reports below show how decisions that made sense to the people involved at the time led to an accident, and what others can learn from them.

The investigations

The Boeing 767 freighter N1217A.
NTSB · 2019

Atlas Air Flight 3591

· Boeing 767-375BCF (converted freighter)
A 767 freighter's go-around mode engaged by accident in turbulence; the first officer, disoriented, pushed the aeroplane into a steep dive, and 32 seconds after the mode change it struck the bay.
Loss of controlSpatial disorientationAutomationCRMHuman factors
A Germanwings Airbus A320 registered D-AIPX photographed at Barcelona airport.
BEA · 2015

Germanwings Flight 9525

· Airbus A320-211
The BEA's findings on the deliberate descent of an A320 into the French Alps, the co-pilot's medical certification and the reinforced cockpit door that kept the captain out.
IncapacitationHuman factors
An Asiana Airlines Boeing 777-200ER, registration HL7742.
NTSB · 2013

Asiana Airlines Flight 214

· Boeing 777-200ER
A 777 crew on a visual approach to San Francisco unintentionally left the autothrottle in HOLD at idle, noticed the decaying airspeed only at about 200 ft and struck the seawall after a late go-around.
Approach and landingAutomationCRMFatigueHuman factors
A Delta Air Lines Boeing 717 landing on runway 22 at Blue Grass Airport, Lexington, Kentucky.
NTSB · 2006

Comair Flight 5191

· Bombardier CL-600-2B19 (CRJ-100)
Cleared for runway 22 at Lexington, a CRJ crew lined up in the dark on runway 26, less than half as long, and crashed beyond its end.
Runway incursionHuman factorsCRM
The Helios Airways Boeing 737-300 5B-DBY.
AAIASB · 2005

Helios Airways Flight 522

· Boeing 737-31S (737-300)
A 737 left Larnaca with its pressurisation in manual; the crew mistook the cabin altitude horn, lost consciousness from hypoxia, and the aircraft flew on autopilot until its fuel ran out.
PressurisationIncapacitationMaintenanceCRMHuman factors
A DHL Boeing 757 freighter at Brussels Airport.
BFU · 2002

Überlingen Mid-Air Collision

· Tupolev Tu-154M and Boeing 757-200 freighter (757-23APF)
Two jets cleared at FL360 collided near Lake Constance at night after a late ATC descent instruction to one crew contradicted its TCAS climb advisory; all 71 people on board died.
Mid-air collisionHuman factorsCRM
The recovered vertical stabiliser of American Airlines Flight 587 being lifted by a crane beside a US Army Corps of Engineers vessel.
NTSB · 2001

American Airlines Flight 587

· Airbus A300-605R (A300B4-605R)
An A300-600's fin broke off in the climb when repeated full rudder reversals after a minor wake encounter built loads beyond the ultimate design load.
Structural failureFlight controlsLoss of controlHuman factors
Air Transat Airbus A330-243 C-GITS.
GPIAA · 2001

Air Transat Flight 236

· Airbus A330-243
A fuel leak from a mis-installed engine tube, crossfed instead of isolated, left an A330 without fuel over the Atlantic; the crew glided it to a landing in the Azores.
FuelMaintenanceHuman factorsEngine failure
The Swissair McDonnell Douglas MD-11 HB-IWF at Zurich airport.
TSB · 1998

Swissair Flight 111

· McDonnell Douglas MD-11
A fire hidden above the cockpit ceiling of a Swissair MD-11 spread through flammable insulation during a diversion to Halifax, degrading the aircraft's systems until control was lost and it struck the sea.
FireHuman factorsLoss of control
The British Midland Boeing 737-400 G-OBME at London Heathrow.
AAIB · 1989

British Midland Flight 92 (Kegworth)

· Boeing 737-400
After a fan blade failure in the left engine, the crew of a Boeing 737-400 shut down the right engine; the damaged engine failed on final approach and the aircraft crashed beside the M1.
Engine failureCRMHuman factorsSurvival
Recovery of the tail section of the Air Florida Boeing 737 from the Potomac River.
NTSB · 1982

Air Florida Flight 90

· Boeing 737-222
A Boeing 737 took off in continuing snow with contaminated wings and far less thrust than its iced EPR gauges showed, could not sustain flight after liftoff and struck a bridge over the Potomac.
IcingStallCRMHuman factors

The theory in the Library

More investigations

Picture credits

  1. Atlas Air Flight 3591: Orlando Suarez · CC BY-SA 4.0 · Wikimedia Commons
  2. Germanwings Flight 9525: SEBASTIEN MORTIER · CC BY-SA 2.0 · Wikimedia Commons
  3. Asiana Airlines Flight 214: Tomás Del Coro from Las Vegas, Nevada, USA · CC BY-SA 2.0 · Wikimedia Commons
  4. Comair Flight 5191: Checkerberry · CC0 · Wikimedia Commons
  5. Helios Airways Flight 522: Mila Daniel · CC BY-SA 4.0 · Wikimedia Commons
  6. Überlingen Mid-Air Collision: Koen Gladines · CC BY-SA 4.0 · Wikimedia Commons
  7. American Airlines Flight 587: NTSB · Public domain · Wikimedia Commons
  8. Air Transat Flight 236: Ken Fielding · CC BY-SA 3.0 · Wikimedia Commons
  9. Swissair Flight 111: Aero Icarus from Zürich, Switzerland · CC BY-SA 2.0 · Wikimedia Commons
  10. British Midland Flight 92 (Kegworth): Leslie Snelleman · CC BY-SA 4.0 · Wikimedia Commons
  11. Air Florida Flight 90: FAA · Public domain · Wikimedia Commons

Crash Investigations pages summarise official investigation reports for study and exam preparation. The investigating body's report is the authoritative account and prevails wherever it differs from this page. Under ICAO Annex 13, an investigation exists to prevent accidents, not to apportion blame or liability.