ASN Wikibase Occurrence # 365397
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| Date: | Monday 29 April 1991 |
| Time: | 12:00 LT |
| Type: |  Boeing 747SP |
| Owner/operator: | United Airlines |
| Registration: | N148UA |
| MSN: | 21648/367 |
| Year of manufacture: | 1979 |
| Engine model: | P&W JT9D-7ASP |
| Fatalities: | Fatalities: 0 / Occupants: 102 |
| Aircraft damage: | Minor |
| Category: | Serious incident |
| Location: | Churchville, NY -
 United States of America
|
| Phase: | En route |
| Nature: | Unknown |
| Departure airport: | Newark, NJ (KEWR) |
| (KTYO) | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
THE BOEING 747SP HAD JUST LEVELED OFF AT FL350 AND WAS ACCELERATING FROM M.81 TO M.85. DURING THE ACCELERATION, A VIBRATION WAS FELT IN THE COCKPIT AND CABIN. NO ABNORMAL ENGINE READINGS WERE OBSERVED. THE VIBRATION LASTED FOR ABOUT 2 MINUTES AND WAS FOLLOWED BY A LOUD BANG HEARD IN THE COCKPIT. THE NUMBER TWO ENGINE REVEALED A FAILED SIXTH ROTATING AIRSEAL. METALLURGICAL EXAMINATION OF FAILED AIRSEAL SHOWED FEATURES TYPICAL OF OVERSTRESS WITH NO INDICATION OF PREEXISTING CRACKS.
Probable Cause: A FAILURE OF THE SIXTH ROTATING AIRSEAL WHICH LED TO AN UNCONTAINED ENGINE FAILURE.
Accident investigation:
 |
|
Sources:
NTSB NYC91IA133
Location
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 20-Mar-2024 09:45 | ASN Update Bot | Added |
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