# NTSB CEN22LA085: Beech A100, N93GT, West Helena, AR, December 28, 2021 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: December 28, 2021, 11:50 local (17:50 UTC) - Place: West Helena, AR - Coordinates: 34.576493, -90.675889 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=34.5765&lon=-90.6759&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Unknown or undetermined](https://openairdocs.org/ntsb-events/000) - Highest injury: No injuries - Injuries: 5 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: FAA FSDO, Textron, Hartzell, TSB Canada ACC REP - NTSB case key (mKey): 104451 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN22LA085 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/104451/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=104451 - Page: https://openairdocs.org/ntsb/CEN22LA085 ## Probable cause The malfunction of the propeller autofeather system after takeoff for undetermined reasons, which resulted in both propellers going into feather and a hard landing. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Propeller system: propeller feather/reversing](https://openairdocs.org/ntsb-findings/01046123): Aircraft › Aircraft propeller/rotor · Unknown/Not determined (probable cause); cases with it: [Beech A100, 1 case](https://openairdocs.org/ntsb-findings/01046123/cases.md?model=1152915), [All aircraft, 26 cases](https://openairdocs.org/ntsb-findings/01046123/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff: Unknown or undetermined](https://openairdocs.org/ntsb-events/000) (defining event); cases with it: [Beech A100, 1 case](https://openairdocs.org/ntsb-events/000/sequence.md?model=1152915), [All aircraft, 1,703 cases](https://openairdocs.org/ntsb-events/000/sequence.md) - [Takeoff: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340); cases with it: [Beech A100, 1 case](https://openairdocs.org/ntsb-events/340/sequence.md?model=1152915), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md) - [Landing-flare/touchdown: Hard landing](https://openairdocs.org/ntsb-events/092); cases with it: [Beech A100, 1 case](https://openairdocs.org/ntsb-events/092/sequence.md?model=1152915), [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: [Beech A100, 1 case](https://openairdocs.org/ntsb-events/300/sequence.md?model=1152915), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) ## Analysis The pilot reported that immediately after takeoff, both propeller assemblies went into a feathered condition. The pilot was able to maneuver the airplane back to a runway. After a hard landing, the left tire blew, the airplane exited the runway, and the airplane’s left wing sustained substantial damage. On the day before the accident flight, the airplane underwent maintenance to troubleshoot a propeller autofeather issue. A mechanic tested the autofeather system and replaced a low-pressure switch. After the maintenance, the mechanic conducted operational checks and performed ground runs; no defects were found. The airplane was returned to service, and the pilot flew the airplane the next day, before the accident flight, without any reported mechanical issues. Postaccident examinations of the cockpit control pedestal and feathering systems did not reveal any anomalies. All propeller condition lever controls were intact and had a full range of motion. Both left and right engine throttle controls were intact and had a full range of motion. Inspections of all accessible wiring and components within the engine nacelles, as well as those contained within the cabin of the aircraft and rigging under the floor panels, revealed no anomalies. Examination of both engines’ propeller governors, fuel control units (FCUs) and beta valves did not reveal any anomalies. These detailed examinations could not determine the reason for the reported propeller feather issue on takeoff. ## Factual narrative On December 28, 2021, about 1150 central standard time, a Beech A100 airplane, N93GT, was substantially damaged when it was involved in an accident near West Helena, Arkansas. The pilot and 4 passengers were not injured. The flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 91 as a business flight. The airplane had just been in maintenance on the day before the accident to troubleshoot a propeller feather issue. According to a work order, a mechanic found the low-pressure switch on the left engine to be inoperative, replaced the switch, and performed multiple ground runs and system tests. No further defects were found, and the airplane was returned to service. The pilot was briefed on the issue by maintenance. The pilot then flew the airplane solo from Batesville Regional Airport (PMU), Batesville, Mississippi, to Thompson-Robbins Airport (HEE), West Helena, Arkansas, on the morning of December 28, 2021. The pilot reported that there were no mechanical issues during the flight. The pilot arrived at HEE about 1040, and boarded 4 passengers for a flight to Camilla-Mitchell County Airport (CXU), Camilla, Georgia, and taxied the airplane to runway 18 at HEE for takeoff. Immediately after rotation, the pilot noticed that the engines were not producing normal thrust. He also stated that both propellers were going into feather. There was not enough runway remaining to land safely, so the pilot retracted the landing gear and searched for a suitable emergency landing area. The pilot was able to maneuver the airplane back to runway 18. With the combination of low altitude and insufficient thrust, the pilot was not able to slow the descent to the runway. Upon touchdown, the left tire blew, and the airplane skidded onto the grass adjacent to the runway, which resulted in substantial damage to the left wing’s spar. According to the pilot, he was aware of the emergency procedure for an unexpected propeller feathering. He stated that he was able to reduce power as required to keep the engine within the torque limits, but due to low altitude and heavy workload, he was unable to safely remove his hands from the controls to pull the propeller governor idle stop circuit breaker. An examination of the airplane was conducted on February 23, 2023. Examination of the cockpit control pedestal and feathering systems did not reveal any anomalies. All propeller condition lever controls were intact and had a full range of motion. Both left and right engine throttle controls were intact and had a full range of motion. Examination of all accessible wiring and components within the engine nacelles, as well as those contained within the cabin of the aircraft and rigging under the floor panels, revealed no anomalies. Examination of both engines’ propeller governors, FCUs, and beta valves did not reveal any anomalies. ## Aircraft - Registration: [N93GT](https://openairdocs.org/aircraft/N93GT), registered now, S/N B-179, built 1974 (OpenAirDocs) - Reported make and model: BEECH A100 - Registry model: [Beech A100](https://openairdocs.org/model/beech-a100) (registry code 1152915) (OpenAirDocs) - Registry engine: [Pratt & Whitney Canada PT6A-60A](https://openairdocs.org/engine/pratt-whitney-canada-pt6a-60a) (registry code 52043, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: B-179 - Year built: 1974 - Airframe hours: 8010 - Engines: P&W PT6A-28 (Left) 680 horsepower turbo prop; P&W PT6A-28 (Right) 680 horsepower turbo prop - Damage: Substantial damage - Flight: Business, Part 91 - Registered owner: Sky-Bound Aviation LLC - Airworthiness certificate: Standard, Normal - Last inspection: Annual, November 6, 2021 - Destination: CXU, Camilla, GA - Airport: HEE, Thompson-Robbins, runway 18, 5,001 × 100 ft, asphalt - Equipment: Onboard weather, Auto-pilot, ADS-B, Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 40; injuries: none; airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review October 3, 2021; seat: left; restraint: 4-point; flight hours: 13,550 total, 876 in this make and model, 190 in the last 90 days, 51 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 190° at 16 knots, gusting 24 - Visibility: 10 statute miles - Lowest ceiling: 7,000 ft overcast - Temperature: 73 °F, dew point 68 °F - Altimeter: 29.70 inHg - Observed at: KCKM, 18 nm away - METAR: KCKM 281755Z AUTO 19016G24KT 10SM FEW029 SCT034 OVC070 23/20 A2970 RMK A01 ## 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 20211228021589A](https://openairdocs.org/incident/20211228021589A), Dec 28, 2021: Beech A100, West Helena, AR, Substantial damage. On December 28, 2021 N93GT departed batesville ms (pmu) at approximately 10:28 CST and arrived uneventfully at Helena ar (hee) at approximately 10:40 CST. Upon… ## Docket (9 files) The files NTSB released with the investigation on March 20, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=104451. 6.0 MB in all. - NTSB form 6120 pilot operator report CEN22LA085 (item 1, PDF, 10 pages, 3.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16773544&FileExtension=pdf&FileName=NTSB%20Form%206120%20Pilot%20Operator%20Report%20CEN22LA085_Redacted-Rel.pdf - Pilot statement CEN22LA085 (item 2, PDF, 1 page, 52 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16773295&FileExtension=pdf&FileName=Pilot%20Statement%20CEN22LA085-Rel.pdf - Work order for auto feather system troubleshoot check CEN22LA085 (item 3, PDF, 1 page, 51 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16773637&FileExtension=pdf&FileName=Work%20Order%20for%20Auto%20Feather%20System%20Troubleshoot%20Check%20CEN22LA085_Redacted-Rel.pdf - Excerpt from maintenance manual propeller controldescription and operation CEN22LA085 (item 4, PDF, 5 pages, 623 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16773485&FileExtension=pdf&FileName=Excerpt%20from%20Maintenance%20Manual%20Propeller%20ControlDescription%20and%20Operation%20CEN22LA085-Rel.pdf - Excerpt from maintenance manual troubleshooting practices CEN22LA085 (item 5, PDF, 4 pages, 436 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16772957&FileExtension=pdf&FileName=Excerpt%20from%20Maintenance%20Manual%20Troubleshooting%20Practices%20CEN22LA085-Rel.pdf - Certificate of party representative hartzell CEN22LA085 (item 6, PDF, 1 page, 312 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16773324&FileExtension=pdf&FileName=Certificate%20of%20Party%20Representative%20Hartzell%20CEN22LA085_Redacted-Rel.pdf - Certificate of party representative Textron CEN22LA085 (item 7, PDF, 1 page, 151 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16773524&FileExtension=pdf&FileName=Certificate%20of%20Party%20Representative%20Textron%20CEN22085_Redacted-Rel.pdf - Memorandum for the record excerpt from POH CEN22LA085 (item 8, PDF, 1 page, 265 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16802160&FileExtension=pdf&FileName=Memorandum%20for%20the%20Record%20Excerpt%20from%20POH%20CEN22LA085_Redacted-Rel.pdf - Photo array CEN22LA085 (item 9, PDF, 4 pages, 798 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16801599&FileExtension=pdf&FileName=Photo%20Array%20CEN22LA085-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.