ASN Wikibase Occurrence # 353142
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| Date: | Tuesday 22 June 1999 |
| Time: | 17:03 LT |
| Type: |  Avid Flyer |
| Owner/operator: | Private |
| Registration: | N700RM |
| MSN: | 711 |
| Total airframe hrs: | 608 hours |
| Engine model: | Rotax 582 |
| Fatalities: | Fatalities: 0 / Occupants: 1 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | Poulsbo, WA -
 United States of America
|
| Phase: | En route |
| Nature: | Private |
| Departure airport: | Bremerton, WA (PWT |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
The Rotax engine in the amateur-built airplane seized while in flight. The pilot performed an emergency landing, with the airplane sustaining substantial damage. NTSB examination of the crankshaft, bearings and rods, and associated componentry, found no evidence of a general lack of lubrication. The labyrinth sleeve, located between the two front (PTO, or power takeoff end) bearings showed evidence of circular scoring and material transfer contact between the bore of the sleeve and the crankshaft surface, similar to that which would occur with foreign matter in the clearance space between the sleeve and crankshaft. A portion of what appeared to be a melted bearing retainer ring was found in one bearing. The flat face on the magneto side of the labyrinth sleeve was darkened and contained foreign material deposits which appeared similar in color and nature to the material of the bearing retainer ring. The PTO side of the labyrinth sleeve was configured with a ring at the inner and outer diameters, with a hollowed out region in between. The hollow contained foreign material deposits, as did the surface of the inner diameter ring. Little discoloration was noted on the PTO side of the labyrinth sleeve. The bore of the labyrinth ring showed a large amount of circumferential scoring and material transfer. The corresponding area on the surface of the crankshaft contained similar scoring and material transfer, consistent with contact between these two surfaces. The ball bearings in both of the PTO bearing assemblies were unevenly spaced, indicating that their retainer rings were either lost or somehow ineffective in keeping the balls evenly spaced.
Probable Cause: Engine seizing due to failure of main bearing assemblies. Factors include foreign material in the labyrinth sleeve, and a stall encountered while the pilot was attempting his emergency landing.
Accident investigation:
 |
|
Sources:
NTSB SEA99LA093
Location
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 09-Mar-2024 10:49 | ASN Update Bot | Added |
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