Great Lakes 2T-1A-2 N765GL

Summary

On 14 May 2005 at about 17:30 local time, a Great Lakes 2T-1A-2 registered N765GL was involved in an accident near Sonoma, California, 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

14 May 2005 at 17:30

Classification

Accident

Location

Sonoma, California, United States

Nearest airport

Sonoma Valley Airport (0Q3)

Coordinates

38.2233, -122.4494

Aircraft

Great Lakes 2T-1A-2

Registration

N765GL

Category

Airplane

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Sonoma → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

LAX05LA173

1 person had minor injuries.

a partial loss of engine power, which resulted from the fuel servo leaking and generating an excessively rich fuel/air mixture. A factor was the owner's failure to comply with a service bulletin.

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

Read the full NTSB narrative

The airplane collided with the runway during an aborted takeoff following a partial loss of engine power. Prior to departure the pilot completed an engine run-up, observing no anomalies with the engine gauges or the engine's performance. During the takeoff, as the pilot began to lift off of the runway surface, the engine began to surge and he noticed a subsequent degradation in climb performance. After reaching about 30 to 40 feet above ground level (agl), he realized the airplane would not be able to continue the departure and opted to perform an emergency landing on an alternate runway. The airplane collided with the runway in a 15-degree nose low attitude. A post accident examination of the engine found that the spark plugs, the cylinders, and piston heads were heavily sooted; signatures consistent with an excessively rich fuel mixture. No other anomalies were found that would have precluded the engine from normal operation. An examination of the fuel servo revealed that the unit had a black coloration in the throat section and blue staining present near the idle valve. These signatures were consistent with a rich fuel mixture and a continuous fuel leak. During the bench testing of the servo, several small fuel leaks were noted at the idle valve, fuel diaphragm, and center body seal. Flow tests at high power settings revealed that the fuel servo was running rich, well over the prescribed maximum flows for that unit. The unit was about 28 years old and did not appear to have ever been overhauled. A representative from the engine manufacturer stated that based on the fuel servo's tested flow, the engine would have been running very rich and most likely could not have produced normal power. The servo manufacturer issued a Service Bulletin in 1990 that recommends that the unit be overhauled at engine TBO or every 10 years.

Quoted verbatim from the NTSB record.