# NTSB CEN23LA231: Cessna 207, N91157, Harlingen, TX, June 6, 2023 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: June 6, 2023, 12:08 local (17:08 UTC) - Place: Harlingen, TX - Coordinates: 26.228099, -97.658703 - Nearby events: https://openairdocs.org/map.md?lat=26.2281&lon=-97.6587&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: Continental Aerospace Technologies, Federal Aviation Administration - NTSB case key (mKey): 192328 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN23LA231 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/192328/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=192328 - Page: https://openairdocs.org/ntsb/CEN23LA231 ## Probable cause The improper installation of the throttle control arm to the throttle control cable attachment end, which resulted in a failure of the control arm and a loss of engine power in flight. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine fuel and control: fuel controlling system](https://openairdocs.org/ntsb-findings/01057320): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Cessna 207, 1 case](https://openairdocs.org/ntsb-findings/01057320/cases.md?model=2073602), [All aircraft, 59 cases](https://openairdocs.org/ntsb-findings/01057320/cases.md) - [Maintenance: installation](https://openairdocs.org/ntsb-findings/02062035): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Cessna 207, 1 case](https://openairdocs.org/ntsb-findings/02062035/cases.md?model=2073602), [All aircraft, 371 cases](https://openairdocs.org/ntsb-findings/02062035/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) (defining event); cases with it: [Cessna 207, 1 case](https://openairdocs.org/ntsb-events/340/sequence.md?model=2073602), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md) ## Analysis The pilot reported that shortly after takeoff on the fourth flight of the day, he leveled the airplane about 500 ft above ground level (agl), and set the engine controls for 2,500 rpm and 25 inHg manifold pressure. Immediately after adjusting the engine controls, the engine speed decreased to idle. The pilot made a forced landing to a field and the airplane sustained substantial damage to the left wing. A postaccident examination revealed that the throttle control lever had fractured, and the throttle control was no longer connected. The associated hardware remained attached to the throttle control cable attachment end. The engine and fuel control valve were recently overhauled, reinstalled in the airplane, and had accumulated 86.3 hours. A postaccident metallurgical examination revealed the throttle control lever attachment point exhibited wear and deformation on the surfaces of the areas that would have been in contact with the rod end attachment hardware. The throttle control lever attachment point also exhibited wear and a shallow impression of the splined collar on the inner surface of the attachment point bore, which was significantly worn. The splines on the collar were worn and uneven. The wear and deformation to the throttle control lever attachment point and the wear in the attachment point’s bore resulted in dimensions that no longer provided enough interference with the rod end attachment hardware to secure the connection. The throttle linkage hardware build-up on the accident airplane was different than specified by the airplane service manual and was missing a washer. The difference likely resulted in the hardware becoming loose over time and allowing excessive wear of the splined collar and lever arm, and ultimately the failure of the lever arm attachment point. ## Factual narrative On June 6, 2023, about 1208 central daylight time, a Cessna 207 airplane, N91157, was substantially damaged when it was involved in an accident near Valley International Airport (HRL), Harlingen, Texas. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 aerial application flight. The pilot stated that the purpose of the flight was to distribute sterile fruit flies in the area, and he had already completed three similar flights that morning. After the third flight, the fuel tanks were topped off and additional fruit flies were loaded into the airplane. The pilot departed, proceeded southeast about 500 ft agl, and set the engine controls for 2,500 rpm and 25 inHg manifold pressure. Immediately after adjusting the engine controls, the engine speed decreased to idle. He was unable to fly back to the airport, so he made a forced landing in a field. During the forced landing, the airplane sustained substantial damage to the left-wing spar. A postaccident examination revealed that the throttle control lever had fractured, and the throttle control was no longer connected. The associated hardware remained attached to the rod end. The engine and fuel control valve were overhauled and reinstalled on the airplane April 14, 2023. The engine had accumulated 86.3 hours since overhaul. The fractured throttle control lever and associated hardware were examined by the National Transportation Safety Board Materials Laboratory. The throttle control lever attachment point exhibited plastic deformation on the surfaces of the areas that would have been in contact with the rod end attachment hardware. This deformation resulted in a variable thickness across the attachment point. The throttle control lever attachment point also exhibited wear and a shallow impression of the splined collar on the inner surface of the attachment point bore, which was significantly worn. The splines on the collar were worn and uneven. The plastic deformation to the throttle control lever attachment point and the wear in the attachment point’s bore resulted in dimensions that no longer provided enough interference with the rod end attachment hardware to secure the connection. On January 26, 1996, the airplane manufacturer issued Service Bulletin SEB 95-15 Rev 1, Engine Throttle Control Lever Inspection. The SEB was issued due to wearing at the throttle control cable attachment end, where in some cases the wear progressed through the lever allowing the throttle control end to become disconnected from the lever. The SEB warned that failure to complete the inspection could result in the loss of engine throttle control and an incontrollable reduction in engine power to idle rpm in flight. The SEB and the airplane service manual provided a diagram of the proper throttle linkage hardware build up. The throttle linkage hardware build-up on the accident airplane was different than the service manual and was missing a washer. ## Aircraft - Registration: [N91157](https://openairdocs.org/aircraft/N91157), registered now, S/N 20700096, built 1969 (OpenAirDocs) - Reported make and model: CESSNA 207 - Registry model: [Cessna 207](https://openairdocs.org/model/cessna-207) (registry code 2073602) (OpenAirDocs) - Registry engine: [Continental IO-520 series](https://openairdocs.org/engine/continental-io-520-series) (registry code 17032, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 20700096 - Year built: 1969 - Airframe hours: 4850 - Engines: Continental Motors IO-520-F 300 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 91 - Operator: Garza Aircraft Inc - Registered owner: Garza Aircraft Inc - Airworthiness certificate: Standard, Normal - Last inspection: Annual, April 17, 2023, 86.3 hours before - Flight plan: Company VFR - Airport: HRL, Valley Intl, runway 17L, 5,949 × 150 ft, asphalt - Equipment: Stall warning system, ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 28; injuries: none; flight instructor, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review October 3, 2022; seat: left; restraint: lap only; flight hours: 2,231 total, 74 in this make and model, 2,129 as pilot in command, 136 in the last 90 days, 51 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 86 °F, dew point 73 °F - Altimeter: 29.90 inHg - Observed at: KHRL - METAR: KHRL 061652Z 00000KT 10SM CLR 30/23 A2990 RMK AO2 SLP125 T03000228 ## 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 20230606006749A](https://openairdocs.org/incident/20230606006749A), Jun 6, 2023: Cessna 207, Harlingen, TX, Substantial damage. Pilot lost power during climb and landed aircraft in field with tall crops, damaged left wing forward spar. Aircraft damage detrimined substantial in… ## Other investigations on N91157 (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 ANC85LA179](https://openairdocs.org/ntsb/ANC85LA179), Sep 18, 1985: Cessna 207 (N91157), Chuathbaluk, AK, substantial damage ## Docket (11 files) The files NTSB released with the investigation on August 29, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=192328. 100 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 5.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15717602&FileExtension=pdf&FileName=6120%20-%20pilot_Redacted-Rel.pdf - Photos (item 2, PDF, 6 pages, 5 photos, 2.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17240357&FileExtension=pdf&FileName=Docket%20photos-Rel.pdf - Maintenance records (item 3, PDF, 3 pages, 66.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15717188&FileExtension=pdf&FileName=Mx%20records_Redacted-Rel.pdf - Engine overhaul work order excerpts (item 4, PDF, 6 pages, 21.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17240962&FileExtension=pdf&FileName=Overhaul%20Work%20Order%20excerpt_Redacted-Rel.pdf - Photos - throttle control arm and rod end installation (item 5, PDF, 3 pages, 1.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17239855&FileExtension=pdf&FileName=N91157%20C207%20throttle%20control%20lever%20figures-Rel.pdf - Correspondence - mechanic (item 6, PDF, 1 page, 73 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17244104&FileExtension=pdf&FileName=ROC%20-%20Mechanic-Rel.pdf - Materials laboratory factual report 23-103 (item 7, PDF, 12 pages, 8 photos, 2.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16806803&FileExtension=pdf&FileName=Materials%20Laboratory%20Factual%20Report%2023-103-Rel.pdf - Cessna 207 service manual excerpt - engine controls (item 8, PDF, 3 pages, 309 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17241150&FileExtension=pdf&FileName=Pages%20from%20Cessna%20207%20service%20manual%20-%20chap12%20engine-Rel.pdf - Cessna service bulletin SEB95-12 rev 1 (item 9, PDF, 13 pages, 516 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17240367&FileExtension=pdf&FileName=Cessna%20%20SEB95-15%20Rev%201%20Throttle%20control%20lever%20inspection-Rel.pdf - Statement of party representatives to NTSB investigation (item 10, PDF, 1 page, 134 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15718055&FileExtension=pdf&FileName=Party%20form%20-%20CMI_Redacted-Rel.pdf - Release of aircraft wreckage, NTSB form 6120.15 (item 11, PDF, 1 page, 149 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15719499&FileExtension=pdf&FileName=Wreckage%20Release%20Form%20-%20N91157%20(CEN23LA231)%20signed_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.