Modrow AVID FLYER N700RM

Summary

On 23 June 1999 at about 00:03 local time, a Modrow AVID FLYER registered N700RM was involved in an accident near Poulsbo, Washington, United States. One person was on board and one had minor injuries. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

23 June 1999 at 00:03

Classification

Accident

Location

Poulsbo, Washington, United States

Coordinates

47.7504, -122.6100

Aircraft

Modrow AVID FLYER

Registration

N700RM

Category

Airplane

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Bremerton → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

SEA99LA093

1 person had minor injuries.

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.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

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.

Quoted verbatim from the NTSB record.