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Case Study #213 — 300 Software Failure Case Studies

China Airlines Flight 140 crash (Nagoya)

An Airbus A300 crashed while landing at Nagoya, Japan, killing 264 of the 271 people aboard.

1994-04-26
When it happened
Aviation
Sector
#213 of 300
Ranked by documented impact
01 — What Happened

The damage was public. The root cause was preventable.

An Airbus A300 crashed while landing at Nagoya, Japan, killing 264 of the 271 people aboard.

Aviation
Sector affected
1994-04-26
Date of the event
#213
Rank in the 300 Software Failure Case Studies
3
Distinct root-cause clauses identified below
02 — The Root Cause

What the software actually got wrong

The first officer inadvertently triggered the autopilot's go-around mode, and as he continued pushing the control column forward against it, the autopilot progressively applied more nose-up trim to try to achieve the commanded climb; the automation and the crew fought each other for control until the aircraft stalled and crashed.

01Root Cause

The first officer inadvertently triggered the autopilot's go-around mode

What Happened

The first officer inadvertently triggered the autopilot's go-around mode

How Requs AI Catches This

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.

02Root Cause

As he continued pushing the control column forward against...

What Happened

as he continued pushing the control column forward against it, the autopilot progressively applied more nose-up trim to try to achieve the commanded climb

How Requs AI Catches This

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.

03Root Cause

The automation and the crew fought each other for...

What Happened

the automation and the crew fought each other for control until the aircraft stalled and crashed

How Requs AI Catches This

Requs AI Edge Case and Software FMEA together treat this as a known, catalogued defect pattern — not a novel surprise — so it gets tested for deliberately rather than discovered after deployment.

03 — How This Gets Caught Before It Happens

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.

Requs AI Edge Case

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.

Requs AI Software FMEA

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.