ASN Wikibase Occurrence # 367830
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| Date: | Wednesday 18 October 1989 |
| Time: | 01:15 LT |
| Type: | Mcdonnell Douglas DC-9 |
| Owner/operator: | Northwest Airlines |
| Registration: | N922RW |
| MSN: | 47182 |
| Total airframe hrs: | 61931 hours |
| Engine model: | P&W JT8D |
| Fatalities: | Fatalities: 0 / Occupants: 103 |
| Aircraft damage: | Minor |
| Category: | Serious incident |
| Location: | Monte Vista, CO -
 United States of America
|
| Phase: | En route |
| Nature: | Unknown |
| Departure airport: | Minneapolis, MN (MSP |
| Phoenix, AZ (KPHX) | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
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.
Probable Cause: 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.
Accident investigation:
 |
|
Sources:
NTSB DEN90IA012
Location
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 22-Mar-2024 19:18 | ASN Update Bot | Added |
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