CEN22LA002

NTSB accident investigation · Beech B23 · Lamesa, TX · October 2, 2021

Accident · Minor injuriesClass 3 · LimitedFinal report
Date
October 2, 2021, 12:25 local (17:25 UTC)
Place
Lamesa, TX
Injuries
1 minor
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N6996QBeech B23
Defining event
Maneuvering: Loss of engine power (partial)
Weather
Visual (VMC) · Day
Status
Completed
Report
Approved by Office Director
Investigation class
Class 3
NTSB office
Central Region
Parties
FAA - LBB FSDO
FAA report
20211002016639A
Case key
104040

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

The loss of engine power for a reason that could not be determined.

Findings · 3

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.

Temp/humidity/pressure: conducive to carburetor icingEnvironmental issues › Conditions/weather/phenomena · Effect on equipmentBeech B23: 1 caseAll aircraft: 435 cases
Fuel system: fuel selector/shutoff valveAircraft › Aircraft systems · Incorrect use/operationBeech B23: 3 casesAll aircraft: 176 cases
Not determinedNot determined › Not determined · Unknown/Not determinedBeech B23: 1 caseAll aircraft: 2,247 casesProbable cause

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

Analysis

The airplane was on the first flight following an annual inspection in which the carburetor had been changed along with other maintenance. The pilot reported that, during the preflight inspection, both fuel tanks were full and everything was normal except for a non-working rotating beacon. She reported that the engine started normally, and the engine checks were normal except that the engine rpms were slightly lower than before the carburetor replacement. The pilot performed one takeoff and landing without difficulty. On the ensuing takeoff, when the airplane reached the departure threshold, the engine power reduced to idle. The pilot made a forced landing in a field and the airplane sustained substantial damage to the right wing. The pilot reported that she did not use carburetor heat during the takeoff or landing because the temperature was above 75° F and the humidity was low; however, the temperature and dewpoint recorded at the accident airport were favorable for serious carburetor icing at glide power settings. Postaccident examination revealed that the fuel selector valve was not in a detent and was positioned between the left and off positions. The pilot stated she did not move the fuel selector valve during or after the flight. Investigators were unable to determine when the fuel selector valve was moved to this position. The postaccident examination also revealed that a cotter pin was not installed on the nut and bolt that secured the throttle cable to the carburetor throttle arm; however, the nut and bolt were still in their proper position and finger tight and did not prevent normal operation of the throttle. The right fuel tank was found full of fuel and the left tank was empty after the accident. The fuel tanks were not compromised and no leaks were noted. The reason the left fuel tank was empty when the pilot had verified it was full before the flight could not be determined. No other mechanical discrepancies were found that would have prevented normal operation. Based on the available information, the loss of engine power could have been the result of improper fuel selector positioning, which reduced fuel flow and starved the engine for fuel, fuel starvation due to inadequate fuel supply from the left fuel tank, or the pilot’s failure to use carburetor heat during the flight when conditions were conducive for serious carburetor icing. The reason for the loss of engine power could not be determined due to the multiple possibilities discovered during postaccident examination.

Factual narrative

On October 2, 2021, about 1225 central daylight time, a Beech 23 airplane, N6996Q, was substantially damaged when it was involved in an accident near the Lamesa Municipal Airport (LUV), Lamesa, Texas. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that the airplane had just undergone an annual inspection that included replacement of the carburetor. She said that she returned to the maintenance facility several times because work that was requested had not been performed or noted discrepancies had not been repaired. On the day of the accident, the pilot planned to perform three takeoffs and landings before departing the area to fly the airplane to her home airport. She performed a preflight inspection, noting the only discrepancy being a non-working rotating beacon. She verified that both fuel tanks were full. Engine start, taxi and run-up were normal except that she noted the idle rpm and full throttle rpm were both slightly lower than before the carburetor replacement. The pilot took off from runway 34 and remained in the traffic pattern, which concluded in a touchdown before mid-field. She noted that she did not use carburetor heat during this landing approach as the temperature was above 75° F and the humidity was low. After touchdown she raised the flaps and applied engine power, performing a touch and go. When the airplane reached the departure end of the runway on the ensuing takeoff, the engine power suddenly reduced to idle. Due to the low altitude the pilot did not attempt to turn the airplane and landed in a field. The airplane sustained substantial damage to its right wing, engine mount, and forward fuselage,. Postaccident examination revealed that the fuel selector valve was not in a detent and was positioned between the left and off positions. The long end of the fuel selector handle was designed to reside between two spring loaded gates to prevent inadvertent selection of the off position during normal operation. The design required that one of the gates be depressed to allow the handle to be rotated to the off position. The handle was found outside of the gated area. The right-wing fuel tank was full of fuel and the left-wing fuel tank was empty. A cotter pin was not installed on the nut and bolt that secured the throttle cable to the carburetor throttle arm; however, the nut and bolt were still in their proper position and finger tight, and did not prevent normal operation of the throttle. No other mechanical discrepancies were found during the postaccident examination. In the pilot’s statement, she noted that the fuel selector handle was attached 180 degrees off. She noted that she, previous owners, and instructors were not aware of this and had always used the long end of the handle as an indicator of fuel selector position. According to the Federal Aviation Administration inspector that responded to the accident, the fuel selectorhandle was properly installed, but the pilot believed that the long end of the fuel selector handle was the indicator that was to be used to determine the fuel selector position. The fuel selector handle had a white triangular arrow on the opposite end from the long end of the handle that was to be used to indicate the selected position. The remainder of the handle was red in color. On the accident airplane, the paint on the fuel selector handle was faded and worn and the white triangular portion was also worn making it difficult to discern the triangular pointer. At the time of the accident, the recorded temperature and dewpoint at the accident airport were 22° C (72° F), and 13° C (55° F), respectively. These were in the range of susceptibility for serious icing at glide power settings.

Aircraft

Registration
N6996Q
Reported as
Beech B23
Category
Airplane
Serial number
M-1103
Built
1968
Airframe hours
3,157
Engine
Lycoming O-360-A2G, 180 horsepower, reciprocating
Damage
Substantial damage
Flight
Personal · Part 91
Airworthiness certificate
Standard, Normal
Last inspection
Annual · August 9, 2021
Departed
LUV · Lamesa, TX
Airport
LUV · Lamesa Muni
Equipment
Satellite tracking device, Handheld GPS, Stall warning system, ADS-B

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
23
Injuries
None
Certificate
Private
Airplane ratings
Single-engine land
Medical
Class 3, With waivers/limitations
Last flight review
August 29, 2020
Seat
Left
Restraint
Lap only
Flight hours
107 total · 67 in this make and model · 55 as pilot in command · 1 in the last 90 days · 0 in the last 30 days · 0 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
Calm
Visibility
10 statute miles
Lowest ceiling
None
Temperature
72 °F, dew point 55 °F
Altimeter
30.19 inHg
Observed at
KLUV
METAR
METAR KLUV 021735Z AUTO 00000KT 10SM 22/13 A3019 RMK AO2=

Docket · 7

The files NTSB released with the investigation on August 16, 2023, on NTSB’s docket system: statements, records, photos and specialists’ reports. 7.1 MB in all.

FAA reports on this event · 1

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