NTSB CAROL · Event
Event CHI90FA278
Aircraft involved
Probable cause & findings
THE INTENTIONAL ACTIVATION OF THE AUXILLARY POWER UNIT BY THE FLIGHT ENGINEER, AND THE IMPROPER EVACUATION PROCEDURES BY THE PILOT IN COMMAND. AN ASSOCIATED FACTOR IN THE ACCIDENT WAS THE APU CIRCUIT BREAKERS WERE NOT PULLED BY COMPANY MAINTENANCE PERSONNEL.
Factual narrative
FOUR PASSENGERS WERE INJURED DURING THE EMERGENCY EVACUATION FOLLOWING AN APU FIRE. THE CREW REPORTED THE APU FIRE BELL WHILE TAXIING. THE CAPT. ELECTED TO EVACUATE, BUT DID NOT INDICATE THE NATURE OF THE PROBLEM TO EITHER THE CABIN ATTENDANTS OR PASSENGERS. SEVERAL PASSENGERS USED THE OVERWING EXITS ON THE SAME SIDE AS THE FIRE AND WERE INJURED JUMPING OFF THE WING. ONE SAID THAT THE WING FLAPS WERE NOT LOWERED DURING THE EVACUATION. THE APU HAD BEEN PLACARDED INOPERATIVE PRIOR TO THE FLIGHT. CREW ADVISED IN WRITING. THE COCKPIT VOICE RECORDER TAPE WAS ERASED IN THE COCKPIT AFTER THE ACCIDENT, SO THE FLIGHT CREW'S ACTIVITIES WERE NOT ABLE TO BE REVIEWED. POST ACCIDENT EXAMINATION OF THE APU REVEALED THAT THE FIRE STARTED BECAUSE OF AN ATTEMPTED START OF THE DEFECTIVE UNIT. PRIOR TO THE FLIGHT, NWA MAINTENANCE ATTEMPTED TO MAKE THE APU INOPERABLE FROM THE COCKPIT BY OPENING CIRCUIT BREAKERS. THE WRONG CIRCUIT BREAKER WAS FULLED, LEAVING THE APU OPERABLE. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12
Verbatim from NTSB's published report. Source file
NTSB_1990_CHI90FA278.txt.
Findings + structured fields enriched from FAA avall.mdb.
Full investigation docket on
data.ntsb.gov ↗.
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Related research
What the literature says.
Academic papers and agency reports matching this event's aircraft type or causal vocabulary (maintenance). Sourced from NASA NTRS, NTSB Safety Studies, FAA CAMI, AOPA Air Safety Institute, Embry-Riddle Scholarly Commons, arXiv, and the Semantic Scholar academic graph.
- Embry-Riddle Scholarly Commons 2026 · Journal article (IJAAA)
From Reactive to Predictive: A hybrid Trust-Mediated Adoption Framework for Data-Driven Maintenance in Distributed-Authority Aviation Environments
Modern aviation maintenance operates within increasingly data-intensive technological environments, yet the operational integration of predictive maintenance into routine decision-making remains incon…
- Semantic Scholar 2025 · Article (Applied Sciences)
Decision-Making Framework for Aviation Safety in Predictive Maintenance Strategies
The implementation of predictive maintenance (PM) in aviation presents unique challenges due to strict safety requirements, complex operational environments, and regulatory constraints.
- Embry-Riddle Scholarly Commons 2024 · Journal article (JAAER)
Low-Resource Automatic Speech Recognition Domain Adaptation – A Case-Study in Aviation Maintenance
With timeliness and efficiency being critical in the aviation maintenance industry, the need has been growing for smart technological solutions that optimize and streamline the different underlying ta…
- Embry-Riddle Scholarly Commons 2024 · Journal article (JAAER)
A New Trajectory in UAV Safety: Leveraging Reinforcement Learning for Distance Maintenance Under Wind Variations
In the field of aviation, safety is a critical cornerstone, and the operation of Unmanned Aerial Vehicle (UAV) systems is deeply connected with this principle.
- Embry-Riddle Scholarly Commons 2024 · Journal article (IJAAA)
Just Culture in Aviation: A Metaphorical Study on Aircraft Maintenance Students
Just Culture, a sub-dimension of safety culture, has been a prominent and debated topic in aviation safety in recent years.
- Embry-Riddle Scholarly Commons 2024 · Journal article (IJAAA)
Performance PRISM: A Comprehensive Framework For Performance Measurement In Aircraft Maintenance
Aircraft maintenance is governed by rigorous safety requirements and high operational complexity, demanding robust performance measurement frameworks to ensure optimal maintenance practices.
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