Aviation Accident Summaries

Aviation Accident Summary LAX98LA243

TEMECULA, CA, USA

Aircraft #1

N2720V

Beech 35

Analysis

The pilot initiated a go-around at 50 to 75 feet agl due to excessive airspeed, and as he applied full throttle, the engine went to idle. He turned the aircraft toward a street and impacted the terrain about 1/2 mile from the airport. The Safety Board conducted a teardown inspection of the engine and discovered that the throttle linkage was disconnected. The bolt that connects the throttle cable to the throttle control rod end bearing was protruding out of the extension sleeve by only two threads. The aircraft had only flown approximately 1 hour since the annual inspection earlier in the month. The pilot did not report any mechanical problems with the aircraft prior to the accident sequence.

Factual Information

On July 24, 1998, at 1228 hours Pacific daylight time, a Beech 35, N2720V, impacted terrain about 1/2 mile from the French Valley Airport in Temecula, California. The aircraft was destroyed and the private pilot, the sole occupant, sustained minor injuries. The personal flight originated at the Pauma Valley, California, airport at 1200 and no flight plan was filed. Visual meteorological conditions prevailed. The pilot reported that he entered a left downwind for runway 18. He reported that he pulled the power back, but the manifold pressure gauge indicated 25 inches of manifold pressure. The pilot stated that as he lined up with the runway but his airspeed was too high, so he decided to do a go-around. About midway down the field at 50 to 75 feet agl, he applied full throttle and retracted the landing gear. He reported that the engine remained at idle speed, indicating 900 to 1000 rpm. The pilot stated that he knew he wouldn't be able to land on the runway, so he turned about 20 degrees to the right and headed for an area where the terrain sloped down. He lowered the landing gear and aligned the aircraft with a street, but realized there were power lines in his way. The aircraft impacted the terrain about 1/2 mile from the airport. The pilot did not report experiencing any mechanical problems with the aircraft prior to the accident sequence. The Safety Board conducted a teardown inspection of the engine on July 30, 1998. There was no external evidence of catastrophic engine failure. The crankshaft was rotated with thumb compression and accessory gear train and valve action continuity was verified in all cylinders. The engine cowling was opened and it was observed that the throttle linkage was disconnected, with only about two threads of the connecting bolt (connects to throttle control rod end bearing) extending out of the throttle extension sleeve. According to the Beechcraft Parts Catalog schematic for the throttle control and landing gear warning switch, the throttle cable end is threaded through the landing gear warning switch actuator into the throttle cable extension sleeve. The throttle cable extension sleeve is threaded into the throttle control rod end bearing. There is an inspection hole in the throttle cable end for the mechanic to verify the engagement depth of the throttle cable. A copy of the throttle control schematic is appended to this file. The aircraft had only flown approximately 1 hour since receiving an annual inspection on July 1, 1998. The Beechcraft Maintenance manual checklist for a 100-hour/annual inspection directs the mechanic to check all engine controls and associated equipment for condition, attachment, alignment, and rigging. A copy of the relevant portions of the Beechcraft Maintenance Manual is appended to this file.

Probable Cause and Findings

A partial loss of engine power due to a disconnected throttle linkage, which was the result of an inadequate maintenance installation/inspection.

 

Source: NTSB Aviation Accident Database

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