# NTSB CEN23LA367: Cessna 172B, N7509X, San Angelo, TX, June 17, 2023 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: June 17, 2023, 08:45 local (13:45 UTC) - Place: San Angelo, TX - Coordinates: 31.357748, -100.4963 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=31.3577&lon=-100.4963&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach-VFR pattern downwind: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 192893 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN23LA367 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/192893/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=192893 - Page: https://openairdocs.org/ntsb/CEN23LA367 ## Probable cause A partial loss of engine power due to loose bolts holding the carburetor throttle body to the fuel bowl. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine fuel and control: fuel control/carburetor](https://openairdocs.org/ntsb-findings/01057322): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Cessna 172B, 1 case](https://openairdocs.org/ntsb-findings/01057322/cases.md?model=2072406), [All aircraft, 195 cases](https://openairdocs.org/ntsb-findings/01057322/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Approach-VFR pattern downwind: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Cessna 172B, 4 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=2072406), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Landing: Hard landing](https://openairdocs.org/ntsb-events/092); cases with it: [Cessna 172B, 2 cases](https://openairdocs.org/ntsb-events/092/sequence.md?model=2072406), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md) - [Landing-landing roll: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [Cessna 172B, 3 cases](https://openairdocs.org/ntsb-events/300/sequence.md?model=2072406), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) ## Analysis The pilot reported that shortly after takeoff the engine began running rough and the engine lost partial power. The pilot made a forced landing back to the departure airport. During the landing, the airplane touched down hard and departed the side of the runway, which resulted in substantial damage to the left wing. Postaccident examination of the carburetor revealed fuel stains around the outside of the fuel bowl and in the throat of the fuel bowl. Five of the six bolts holding the throttle body to the fuel bowl were found only finger-tight. The partial loss of engine power was most likely the result of air being drawn into the fuel bowl due to the loose bolts. The last annual inspection was completed on the engine in January of 2023. Investigators did not determine the last time maintenance was specifically performed on the carburetor. ## Factual narrative On June 17, 2023, about 0845 central daylight time, a Cessna 172B, N7509X, was substantially damaged during a forced landing at San Angelo Regional Airport (SJT), San Angelo, 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 after departure from runway 36 the engine began running rough and a partial loss of power occurred. The pilot flew a forced landing to runway 9, during which the engine continued to run rough. The airplane touched down hard and departed the side of the runway, which resulted in substantial damage to the left wing. Postaccident examination of the carburetor revealed fuel stains around the outside of the fuel bowl. Five of the six bolts holding the throttle body to the bowl were found finger-tight. The float setting was set overly rich and wear was observed on the tip of the float needle. The last annual inspection was completed on the engine on January 1, 2023. Investigators did not determine the last time maintenance was specifically performed on the carburetor. The airplane had flown about 13 hours since the last annual inspection was completed on the airplane. ## Aircraft - Registration: [N7509X](https://openairdocs.org/aircraft/N7509X), registered now, S/N 17248009, built 1960 (OpenAirDocs) - Reported make and model: CESSNA 172B - Registry model: [Cessna 172B](https://openairdocs.org/model/cessna-172b) (registry code 2072406) (OpenAirDocs) - Registry engine: [Continental 0-300-D](https://openairdocs.org/engine/continental-0-300-d) (registry code 17176, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 17248009 - Year built: 1960 - Airframe hours: 3140 - Engines: Lycoming O-360-AF16D 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, January 1, 2023, 13 hours before - Departed: SJT, San Angelo, TX - Destination: SJT, San Angelo, TX - Airport: SJT, San Angelo Regional Airport, runway 9, 4,406 × 75 ft, asphalt - Equipment: Handheld GPS, ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 72; injuries: none; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, unknown; last flight review May 10, 2022; seat: left; restraint: 3-point; flight hours: 1,450 total, 399 in this make and model, 10 in the last 90 days, 2 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Temperature: 73 °F, dew point 70 °F - Altimeter: 29.92 inHg - Observed at: SJT ## 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 20230617011779A](https://openairdocs.org/incident/20230617011779A), Jun 17, 2023: Cessna 172B, San Angelo, TX, Substantial damage. On June 17, 2023, at 0845 CDT, a Cessna 172 experienced a hard landing at the San Angelo regional airfield in San Angelo, Texas. The pilot requested to return… ## Other investigations on N7509X (1) 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. - [NTSB DIA69F0036](https://openairdocs.org/ntsb/DIA69F0036), Jul 30, 1968: Cessna 172 (N7509X), Richmond, VA, substantial damage ## Docket (4 files) The files NTSB released with the investigation on September 5, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=192893. 4.3 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 2.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16394564&FileExtension=pdf&FileName=6120%20....._Redacted-Rel.pdf - FAA correspondence (item 2, PDF, 1 page, 133 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16395743&FileExtension=pdf&FileName=Examination%20Correspondence-Rel.pdf - Engine logs - excerpt (item 3, PDF, 2 pages, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16395576&FileExtension=pdf&FileName=Engine%20Logs%20-%20Excerpt_Redacted-Rel.pdf - Carburetor exam report (item 4, PDF, 2 pages, 473 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16394152&FileExtension=pdf&FileName=Carb%20Exam%20Report_Redacted-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.