Cessna 150 N51172

Summary

On 5 July 2009 at about 20:01 local time, a Cessna 150 registered N51172 was involved in an accident near South Lake Tahoe, California, United States. One person was on board and one died. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

5 July 2009 at 20:01

Classification

Accident

Location

South Lake Tahoe, California, United States

Nearest airport

Lake Tahoe (TVL)

Coordinates

38.8881, -119.9942

Aircraft

Cessna 150

Registration

N51172

Category

Airplane

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

South Lake Tahoe → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR09FA326

1 person died.

A partial loss of engine power due to a malfunctioning carburetor and the pilot’s failure to maintain adequate airspeed while maneuvering to return to the runway. Contributing to the accident was the high density altitude.

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

Read the full NTSB narrative

Witnesses stated that the airplane lifted off and climbed to about 100 feet above the runway in an unusually high nose-up pitch attitude before turning left and descending into terrain. The pilot transmitted a "mayday" call on the Common Traffic Advisory Frequency just before the airplane entered the left turn. During postaccident testing of the engine, excessive vibration occurred as the rpm increased, and one of the spark plugs became excessively sooty, indicating an overly rich fuel/air mixture. The carburetor was then replaced and the engine ran normally at all power test points; the previously sooty spark plug was normal after this test. The accident carburetor was then examined, and a pin that secures the carburetor’s metal floats to their pivot point in the carburetor bowl was missing. Marks indicating contact on the edge of a float and on the side of the bowl were found, indicative of rubbing interference with the side of the bowl. The float-to-bowl contact likely altered the fuel quantity in the bowl, which likely created an overly rich mixture that would have further reduced available engine power at the high density altitude at which the airplane was being operated. The density altitude was calculated to be 8,708 feet. High density altitude adversely affects airplane climb performance and requires pilot vigilance to maintain adequate airspeed during takeoff and climb.

Quoted verbatim from the NTSB record.