LAX01TA233

NTSB accident investigation · Cessna 150 · Delano, CA · July 3, 2001

Accident · No injuriesFinal report
Date
July 2, 2001, 17:34 local (Jul 3, 2001, 00:34 UTC)
Place
Delano, CA
Injuries
2 uninjured
Damage
Substantial damage
Phase of flight
Enroute
Aircraft
N6475TCessna 150
Weather
Visual (VMC) · Day
Status
Completed · report October 24, 2002
Report
Approved by Office Director
Parties
FAA Flt Stnds Dist Office
FAA report
20010702015049A
Case key
52636

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

On this page

Probable cause

A bent mixture control valve stem shaft in the carburetor which made pilot control of the mixture inoperative resulting in excessive fuel consumption, and subsequent loss of engine power..

Sequence of events

NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.

Loss of engine power(total) - nonmechanicalCruise - normal
Fluid,fuel - exhaustionCause
Fuel system,carburetor - excessive flow/outputCause
Mixture control - inoperativeCause
Mixture control - bentCause
Forced landingEmergency descent/landing
On ground/water encounter with terrain/waterEmergency landing
Terrain condition - high vegetation

Analysis

The aircraft collided with grapevines and supporting trellises during a forced landing following a loss of engine power. According to the pilot, his passenger fueled the airplane prior to departure. They purposely waited until after they ate lunch and immediately before departure to refuel the airplane in order to obtain the maximum quantity of cool fuel. The passenger had flown about 40 photo missions with the pilot and was aware of the importance of fueling the airplane to maximum capacity. He assured the pilot that the fuel tanks were completely full. The accident occurred 3 hours 34 minutes after departure. The pilot stated that during recovery, 1/2-gallon of fuel was found in the airplane. The pilot also told the Safety Board investigator that he routinely flew the airplane 4 hours to 4 hours 5 minutes and it would require 20- to 20.5-gallons fuel to fill the tanks. The airplane holds 26 gallons fuel, of which 22.5 are usable fuel. The engine was test run and started promptly and ran smoothly. The magneto check and carburetor heat check were normal. The engine did not stop when the mixture control was moved to the idle cutoff position. The inspection revealed that the mixture control arm was loose on its shaft. The carburetor was examined and the mixture control valve stem shaft was found bent and was not inserted into the sleeve in the bowl. According to the representative from the carburetor manufacturer, the carburetor operates in the "full rich" condition at all times when the stem is not inserted in the sleeve and subsequent movement of the mixture control would have no effect. The examination also revealed that the mixture control lever was loose on the shaft and the stop peg traveled beyond the idle cutoff stop pad. The pilot/operator reported that no recent maintenance had been performed on the carburetor.

Factual narrative

On July 2, 2001, at 1734 hours Pacific daylight time, a Cessna 150, N6475T, made a forced landing in a grape vineyard near Delano, California, after a total loss of engine power. An individual was operating the airplane under the provisions of 14 CFR Part 91. The commercial pilot and one passenger were not injured. The airplane sustained substantial damage. The local area flight was operated as a public-use aircraft for the purpose of photographing crops for the U.S. Department of Agriculture. The flight departed from Delano at 1400. Visual meteorological conditions prevailed, and no flight plan had been filed.

According to the pilot, his passenger fueled the airplane prior to departure. They purposely waited until after they ate lunch and immediately before departure to refuel the airplane in order to obtain the maximum quantity of cool fuel. The passenger had flown about 40 photo missions and was aware of the importance of fueling the airplane to maximum capacity. He assured the pilot that the fuel tanks were completely full. The accident occurred 3 hours 34 minutes after departure. The pilot stated that during recovery, 1/2-gallon of fuel was found in the airplane.

The pilot also told the Safety Board investigator that he routinely flew the airplane 4 hours to 4 hours 5 minutes and it would require 20- to 20.5-gallons fuel to fill the tanks. The airplane holds 26 gallons fuel, of which 22.5 are usable fuel.

The engine was test run at the facilities of Valley Aircraft, Tulare, California, under supervision of an Federal Aviation Administration (FAA) inspector from the Fresno Flight Standards District Office (FSDO). The engine started promptly and ran smoothly. The magneto check and carburetor heat check were normal. The engine did not stop when the mixture control was moved to the idle cutoff position. The inspection revealed that the mixture control arm was loose on its shaft.

The carburetor was removed from the engine, without opening or disassembling it, and shipped to the facilities of Precision Airmotive Corporation. The carburetor was examined there, in the presence of an FAA FSDO inspector, on August 23, 2001. The examination revealed that the mixture control valve stem shaft was bent and was not inserted into the sleeve in the bowl. According to the representative from Precision Airmotive, the carburetor operates in the "full rich" condition at all times when the stem is not inserted in the sleeve, and any subsequent movement of the mixture control would have no effect. The examination also revealed that the mixture control lever was loose on the shaft and the stop peg traveled beyond the idle cutoff stop pad. On the flow bench, the full-rich fuel flow was within serviceable limits.

The pilot/operator reported that no recent maintenance had been performed on the carburetor.

Aircraft

Registration
N6475T
Reported as
Cessna 150
Category
Airplane
Serial number
15017875
Airframe hours
7,759
Engine
Continental O-200-A, 100 horsepower, reciprocating
Damage
Substantial damage
Flight
Public aircraft · Part 91
Operator
Randy L. Thompson, doing business as Thompsons Air
Registered owner
Christine L. Lewin
Airworthiness certificate
Standard, Utility
Last inspection
Annual · December 28, 2000 · 223 hours before
Departed
DLO · Delano, CA

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
52
Injuries
None
Certificate
Commercial
Airplane ratings
Single-engine land
Medical
Class 2, Valid Medical--w/ waivers/lim
Last flight review
July 6, 2001
Seat
Left
Flight hours
7,400 total · 600 in this make and model · 250 in the last 90 days · 25 in the last 30 days · 8 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
300° at 11 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
102 °F, dew point 61 °F
Altimeter
29.77 inHg
Observed at
KBFL, 22 nm away

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.