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ASN Wikibase Occurrence # 66294
Last updated: 14 January 2021
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Date:05-JUL-2009
Time:13:01
Type:Silhouette image of generic C150 model; specific model in this crash may look slightly different
Cessna 150J
Owner/operator:Private
Registration: N51172
C/n / msn: 15069814
Fatalities:Fatalities: 1 / Occupants: 1
Aircraft damage: Substantial
Category:Accident
Location:South Lake Tahoe, California -   United States of America
Phase: Initial climb
Nature:Private
Departure airport:South Lake Tahoe, CA (TVL)
Destination airport:Unknown, CA
Investigating agency: 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 carburetorís 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.
Probable Cause: A partial loss of engine power due to a malfunctioning carburetor and the pilotís failure to maintain adequate airspeed while maneuvering to return to the runway. Contributing to the accident was the high density altitude.

Sources:

NTSB: https://www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20090706X61840&key=1


Revision history:

Date/timeContributorUpdates
06-Jul-2009 10:31 slowkid Added
06-Jul-2009 14:44 slowkid Updated
07-Jul-2009 11:00 slowkid Updated
21-Dec-2016 19:25 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
02-Dec-2017 15:49 ASN Update Bot Updated [Other fatalities, Departure airport, Destination airport, Source, Narrative]

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