# NTSB CEN22LA002: Beech B23, N6996Q, Lamesa, TX, October 2, 2021 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 3 · Limited · Final report - Date: October 2, 2021, 12:25 local (17:25 UTC) - Place: Lamesa, TX - Coordinates: 32.756306, -101.92022 - Nearby events: https://openairdocs.org/map.md?lat=32.7563&lon=-101.9202&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: FAA - LBB FSDO - NTSB case key (mKey): 104040 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN22LA002 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/104040/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=104040 - Page: https://openairdocs.org/ntsb/CEN22LA002 ## Probable cause The loss of engine power for a reason that could not be determined. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Temp/humidity/pressure: conducive to carburetor icing](https://openairdocs.org/ntsb-findings/03031030): Environmental issues › Conditions/weather/phenomena · Effect on equipment; cases with it: [Beech B23, 1 case](https://openairdocs.org/ntsb-findings/03031030/cases.md?model=1151240), [All aircraft, 435 cases](https://openairdocs.org/ntsb-findings/03031030/cases.md) - [Fuel system: fuel selector/shutoff valve](https://openairdocs.org/ntsb-findings/01022823): Aircraft › Aircraft systems · Incorrect use/operation; cases with it: [Beech B23, 3 cases](https://openairdocs.org/ntsb-findings/01022823/cases.md?model=1151240), [All aircraft, 176 cases](https://openairdocs.org/ntsb-findings/01022823/cases.md) - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Beech B23, 1 case](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=1151240), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Beech B23, 2 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=1151240), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) ## 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](https://openairdocs.org/deregistered/N6996Q-2022-12-24), registration cancelled 2022-12-24, S/N M-1103, built 1968 (OpenAirDocs) - Reported make and model: BEECH B23 - Registry model: [Beech B23](https://openairdocs.org/model/beech-b23) (registry code 1151240) (OpenAirDocs) - Registry engine: [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series) (registry code 41514, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: M-1103 - Year built: 1968 - Airframe hours: 3157 - Engines: 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 ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 23; injuries: none; 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= ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20211002016639A](https://openairdocs.org/incident/20211002016639A), Oct 2, 2021: Beech B23, Lamesa, TX, Substantial damage. The [privacy data omitted]pilot had the aircraft annual inspection performed by a part 65 facility at the Lamesa airport. The pilot stated they conducted a… ## Docket (7 files) The files NTSB released with the investigation on August 16, 2023, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=104040. 7.1 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 1.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15249756&FileExtension=pdf&FileName=N6996Q%20-%20FORM%206120%20-%20Pilot%20Kristen%20Green_Redacted-Rel.pdf - Maintenance record excerpts (item 2, PDF, 3 pages, 857 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15249320&FileExtension=pdf&FileName=Maintenance%20record%20excerpts_Redacted-Rel.pdf - Pilot logbook excerpts (item 3, PDF, 4 pages, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15249182&FileExtension=pdf&FileName=Pilot%20logbook%20excerpt_Redacted-Rel.pdf - METAR reports for kluv (item 4, PDF, 1 page, 113 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15252807&FileExtension=pdf&FileName=METARS%20KLUV-Rel.pdf - Carburetor icing probability chart (item 5, PDF, 1 page, 334 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15252110&FileExtension=pdf&FileName=Carburetor%20Icing%20Probability%20Graph%20-%20docket-Rel.pdf - Record of conversation with FAA inspector (item 6, PDF, 2 pages, 69 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15253322&FileExtension=pdf&FileName=FAA%20ROC-Rel.pdf - Photos (item 7, PDF, 4 pages, 4 photos, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15458206&FileExtension=pdf&FileName=Photo%20Array-Rel.pdf From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.