Northwest Airlines Flight 255 crash
A McDonnell Douglas MD-82 crashed on takeoff from Detroit after the crew failed to extend flaps and slats, killing 154 of the 155 people aboard plus 2 on the ground.
The damage was public. The root cause was preventable.
A McDonnell Douglas MD-82 crashed on takeoff from Detroit after the crew failed to extend flaps and slats, killing 154 of the 155 people aboard plus 2 on the ground.
What the software actually got wrong
The cockpit's Takeoff Configuration Warning System, designed to sound an alarm if flaps/slats were not properly set, had lost electrical power because a circuit breaker had been pulled and not reset, so the system had no way of detecting or alerting on its own disabled state.
The cockpit's Takeoff Configuration Warning System, designed to sound...
The cockpit's Takeoff Configuration Warning System, designed to sound an alarm if flaps/slats were not properly set, had lost electrical power because a circuit breaker had been pulled and not reset, so the system had no way of detecting or alerting on its own disabled state.
Requs AI Edge Case flags this exact pattern at the requirements and architecture stage — before a single line of code implementing it exists — so the assumption behind it gets challenged while it is still cheap to fix.
Beyond code coverage and "shall" testing
Root causes like this one rarely show up in code coverage or requirements-compliance testing, because nobody wrote a requirement anticipating the specific edge case that broke. Requs AI Edge Case and Requs AI Software FMEA are built to surface exactly this class of overlooked failure mode — before the software is written.
Surfaces this before code exists
Identifies edge cases like this one at requirements and architecture time, using the Common Defect Enumeration to catalog failure patterns seen across hundreds of real-world software failures — including this one.
Connects the failure mode to the hazard
Traces this class of root cause directly to the system-level hazard it can produce, so a defect pattern like this one gets flagged during design review instead of after it ships.
Find the overlooked root causes before they ship.
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