Helios Airways Flight 522 crash
A Boeing 737 flew on autopilot until it ran out of fuel and crashed near Athens after the entire crew and passengers were incapacitated by hypoxia, killing all 121 people aboard.
The damage was public. The root cause was preventable.
A Boeing 737 flew on autopilot until it ran out of fuel and crashed near Athens after the entire crew and passengers were incapacitated by hypoxia, killing all 121 people aboard.
What the software actually got wrong
A pressurization switch was left in the wrong position after maintenance, and the aircraft's cabin-altitude warning horn used the exact same sound as the unrelated takeoff-configuration warning horn, so the crew misdiagnosed the alert as a nuisance takeoff warning rather than a life-threatening loss of cabin pressure.
A pressurization switch was left in the wrong position...
A pressurization switch was left in the wrong position after maintenance
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.
The aircraft's cabin-altitude warning horn used the exact same...
the aircraft's cabin-altitude warning horn used the exact same sound as the unrelated takeoff-configuration warning horn, so the crew misdiagnosed the alert as a nuisance takeoff warning rather than a life-threatening loss of cabin pressure
Requs AI Software FMEA traces this failure mode back to the system-level hazard it feeds, tagging it against the Common Defect Enumeration so it surfaces in review instead of in the field.
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.
Schedule a demonstration, or explore how Requs AI Edge Case and Software FMEA use the Common Defect Enumeration.