NTSB CAROL · Event
Event DEN90IA012
Aircraft involved
Probable cause & findings
THE POOR INFLIGHT PLANNING AND DECISIONS MADE BY THE FLIGHT CREW FOLLOWING THE FAILURE OF THE NUMBER TWO GENERATOR CONSTANT SPEED DRIVE UNIT. CONTRIBUTING FACTORS TO THE ACCIDENT WERE THE FAILURE OF THE NO. 2 GENERATOR CONSTANT SPEED DRIVE UNIT AND THE CREW'S INADVERTENT SHUT DOWN OF THE WRONG GENERATOR WHICH RESULTED IN A COMPLETE LOSS OF ELECTRICAL POWER.
Factual narrative
WHILE IN CRUISE AT FL350 THE NO. 2 GENERATOR CONSTANT SPEED DRIVE (CSD) FAILED AND THE CREW INADVERTENTLY DISCONNECTED THE NO. 1 GENERATOR CSD. ATTEMPTS TO START THE APU ABOVE THE START ENVELOPE WERE MADE BUT ABORTED DUE TO A HOT START. A DESCENT WAS MADE ON EMERG ELECTRICAL POWER AND A LANDING WAS MADE AT AN ARPT WHICH WAS INADEQUATE FOR THE ACFT. THE CREW CHOSE TO MAKE A NO FLAP APCH AND TO LOWER LANDING GEAR BY EMERG METHOD WHEN BOTH SYSTEMS WERE OPERABLE BY NORMAL MEANS. THIS DECISION WAS INFLUENCED BY THE LACK OF LANDING GEAR AND FLAP POSITION INDICATORS WHEN THE ACFT IS OPERATED ON BATTERY POWER. THE LANDING SPEED WAS FAST AND THE ACFT DEPARTED THE END OF THE RWY DAMAGING THE LANDING GEAR AND THE NO. 1 ENGINE. THE CREW FAILED TO MANUALLY DEPRESSURIZE THE ACFT AND THE EVACUATION WAS DELAYED UNTIL A KNOWLEDGEABLE PASSENGER WENT TO THE COCKPIT AND DEPRESSURIZED THE ACFT. THE OPERATORS ACFT OPERATING MANUAL DID CONTAIN APU STARTING PROCEDURES BUT NOT AN APU START ENVELOPE CHART. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12
Verbatim from NTSB's published report. Source file
NTSB_1989_DEN90IA012.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. Sourced from NASA NTRS, NTSB Safety Studies, FAA CAMI, AOPA Air Safety Institute, Embry-Riddle Scholarly Commons, arXiv, and the Semantic Scholar academic graph.
- NASA NTRS 2019 · Preprint (Draft being sent to journal)
Cockpit Interruptions and Distractions: Effective Management Requires a Careful Balancing Act
Managing several tasks concurrently is an everyday part of cockpit operations. For the most part, crews handle concurrent task demands efficiently, yet crew preoccupation with one task to the detrimen…
- NASA NTRS 2019 · Technical Memorandum (TM)
Effects of digital altimetry on pilot workload
A series of VOR-DME instrument landing approaches was flown in the DC-9 full-workload simulator to compare pilot performance, scan behavior, and workload when using a computer-drum-pointer altimeter (…
- NASA NTRS 2013 · Conference Paper
Maintaining the safety of an aging fleet of aircraft
The current status of the Douglas Aging Fleet is examined in light of increasing concern for the possibility of the onset of widespread cracking and recent industry activity to minimize the concern.
- NASA NTRS 2011 · Reprint (Version printed in journal)
Predicted airframe noise levels for certification flights
A correction is presented for a previously published inconsistency in predicted airframe noise values, which were based on approach velocities lower than those required for FAA certification.
Browse the full corpus — academia portal ↗