Cognitive Biases: The Hidden Threat to Pilots & Flight Safety

Cognitive Biases: The Hidden Threat to Pilots & Flight Safety

How Mental Shortcuts Can Lead to Critical Errors in Aviation

Understanding Cognitive Biases in Aviation

Human factors play a critical role in flight safety and daily operations. One of the most significant human factors affecting aviation safety is cognitive biases—mental shortcuts that influence perception, interpretation, and decision-making. While biases can be useful in filtering vast amounts of information quickly, they can also lead to errors and misjudgments that threaten flight safety.

Cognitive biases occur when a pilot’s prior knowledge, expectations, or assumptions interfere with objective decision-making. These biases can lead to overlooked warnings, misinterpretation of data, and unsafe actions. Below are some of the most dangerous cognitive biases that have contributed to real-world aviation accidents.

1. Confirmation Bias

The tendency to search for or interpret information in a way that confirms pre-existing beliefs while ignoring contradictory evidence.

Example: Air France Flight 447 (2009) On June 1, 2009, Air France Flight 447, an Airbus A330 flying from Rio de Janeiro to Paris, crashed into the Atlantic Ocean, killing all 228 people on board. Confirmation bias played a significant role in the accident.

How Confirmation Bias Contributed to the Accident:

• Misinterpretation of Airspeed Data: The aircraft’s pitot tubes froze, causing autopilot disconnection and unreliable airspeed readings. The First Officer assumed an overspeed condition (flying too fast) and pulled back on the controls, unknowingly putting the aircraft into a stall.
• Ignoring Contradictory Warnings: The stall warning sounded multiple times, indicating a low-speed, high-angle-of-attack condition. However, the pilots continued to believe they were in an overspeed condition, reinforcing their false assumption and failing to take corrective action.

2. Expectation Bias

Expectation bias occurs when a person interprets information in a way that aligns with their expectations, even if the actual data suggests otherwise.

Example: Delhi ATC Initial Altitude Clearance If a pilot routinely flies out of Delhi Airport, they may be accustomed to receiving an initial altitude clearance of 7,000 feet from Delhi ATC. One day, ATC assigns a different altitude—5,000 feet—but due to expectation bias, the pilot still assumes it to be 7,000 feet and climbs accordingly. This mismatch can lead to a serious airspace conflict or altitude deviation, creating a safety hazard.

Example: Eastern Air Lines Flight 401 (1972) On December 29, 1972, Eastern Air Lines Flight 401, a Lockheed L-1011 TriStar, crashed into the Florida Everglades while on approach to Miami International Airport, killing 101 people onboard.

How Expectation Bias Contributed to the Accident:

1. Landing Gear Light Distraction: The crew noticed that the landing gear indicator light was not illuminated. Expecting a faulty lightbulb rather than an actual gear problem, the pilots focused on troubleshooting the light instead of manually verifying the landing gear’s position.
2. Autopilot Disengagement Went Unnoticed: The Captain accidentally disengaged the autopilot, causing a slow descent. Expecting the aircraft to be level, the crew failed to monitor altitude changes.
3. Ignored Altitude Warnings: ATC alerted the aircraft about altitude concerns, but the crew assumed everything was normal and did not take corrective action.

3. Plan Continuation Bias (Get-There-Itis)

The tendency to stick to the original plan despite emerging risks, even when changing the plan would be safer.

Example: Avianca Flight 52 (1990) On January 25, 1990, Avianca Flight 52, a Boeing 707 flying from Bogotá, Colombia, to New York’s JFK Airport, crashed due to fuel exhaustion, killing 73 out of 158 people onboard.

How Plan Continuation Bias Contributed to the Accident:

1. Delays and Holding Patterns: The flight was delayed multiple times due to poor weather. The pilots continued holding rather than diverting to a closer airport despite depleting fuel levels.
2. Failure to Declare a Fuel Emergency: The crew did not explicitly declare a Mayday or fuel emergency, instead vaguely stating they were "low on fuel." ATC did not recognize the urgency and did not prioritize their landing clearance.
3. Commitment to the Original Destination: The crew remained focused on landing at JFK rather than choosing closer alternatives (e.g., Newark or Philadelphia). This resulted in fuel exhaustion mid-air, causing all four engines to shut down and the aircraft to crash short of the runway.

Other Critical Cognitive Biases in Aviation

4. Anchoring Bias

Relying too heavily on the first piece of information received (the "anchor") and ignoring new evidence. Example: If ATC initially reports "light turbulence," a pilot may underestimate worsening conditions even when new reports suggest severe turbulence.

5. Authority Bias

Placing too much trust in authority figures, even when their decision appears incorrect. Example: A First Officer hesitates to challenge a Captain’s incorrect decision, fearing conflict or disciplinary action.

6. Status Quo Bias

Preferring to stick to familiar methods rather than adopting safer, updated procedures. Example: A pilot resists new automation or technology, insisting that manual flying is always superior, even when automation provides better safety.

How Pilots Can Overcome Cognitive Biases

✅ Cross-Check Data – Always verify information from multiple sources instead of relying on assumptions.

✅ Encourage Open Communication (CRM) – Crew members should challenge decisions when necessary.

✅ Use Decision-Making Models (FORDEC) – Facts, Options, Risks, Decision, Execution, Check.

✅ Recognize the Impact of Stress and Fatigue – Fatigue increases reliance on cognitive shortcuts.

✅ Practice Scenario-Based Training – Regularly simulate emergencies to enhance adaptive decision-making.

Conclusion

Cognitive biases are one of the most significant hidden threats in aviation. While they help in fast decision-making, they can also lead to critical errors when unchecked. By understanding and mitigating these biases, pilots can improve their situational awareness, decision-making, and overall flight safety.