# NTSB CEN22LA187: North American AT-6D, N29947, Fredericksburg, TX, April 30, 2022 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: April 30, 2022, 13:00 local (18:00 UTC) - Place: Fredericksburg, TX - Coordinates: 30.249215, -98.913705 - Nearby events: https://openairdocs.org/map.md?lat=30.2492&lon=-98.9137&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: Federal Aviation Administration - ADs cited in the narratives: [AD 99-11-02](https://openairdocs.org/ad/99-11-02) (OpenAirDocs) - NTSB case key (mKey): 105032 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN22LA187 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/105032/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=105032 - Page: https://openairdocs.org/ntsb/CEN22LA187 ## Probable cause A total loss of engine power due to a failure of the No. 1 cylinder. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (reciprocating): recip eng cyl section](https://openairdocs.org/ntsb-findings/01058530): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [North American AT-6D, 1 case](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=6400416), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [North American AT-6D, 2 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=6400416), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Landing-aborted after touchdown: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [North American AT-6D, 4 cases](https://openairdocs.org/ntsb-events/300/sequence.md?model=6400416), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) ## Analysis The pilot stated that he completed a preflight inspection and engine run-up with no anomalies noted. During the initial climb after takeoff, immediately after retracting the landing gear, the pilot noticed white smoke from the engine cowling. A few seconds later, the engine “coughed loudly” and lost total power. The pilot landed the airplane on the remaining runway; however, the airplane exited the runway and collided with a runway light. resulting in substantial damage to the left wing and left aileron. Federal Aviation Administration (FAA) inspectors completed an examination of the airplane and assisted the owner’s mechanics with removing the engine for transport. They discovered that the No. 1 cylinder was cracked around its circumference. They did not observe any other anomalies during the examination. Postaccident engine examination confirmed that the No. 1 cylinder head fractured near the rear spark plug on the exhaust side. The mechanic noted it was likely that during the accident takeoff, the cylinder head separated due to pre-ignition or detonation stresses, which no longer allowed the push rods to operate the valves and resulted in a loss of engine power. A recurring FAA airworthiness directive (AD) was applicable for this airplane and related to visual inspections to prevent cylinder head cracking. The AD was completed 164.7 flight hours before the accident and was due to be completed again in 85.3 hours. ## Factual narrative On April 30, 2022, about 1300 central daylight time, a North American AT-6D airplane, N29947, was substantially damaged when it was involved in an accident at Gillespie County Airport (T82), Fredericksburg, Texas. The pilot and passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot stated that he completed a preflight inspection and engine run-up with no anomalies noted. During the initial climb after takeoff, immediately after the landing gear was retracted, the pilot noticed white smoke from the engine cowling. A few seconds later, the engine “coughed loudly” and then lost total power. The airplane was still over the runway, and the pilot extended the landing gear, then retracted it again when he realized that insufficient runway remained for landing. The airplane landed with the right main gear extended and the left main gear partially extended, exited the runway, and collided with a runway light. The airplane sustained substantial damage to the left wing and left aileron. FAA inspectors completed an examination of the airplane and assisted the owner’s mechanics with removing the radial engine for transport. They discovered that the No. 1 cylinder was cracked all the way around the circumference. They did not observe any other anomalies during the examination. Postaccident engine examination confirmed that the No. 1 cylinder head fractured near the rear spark plug on the exhaust side. A review of the airplane maintenance records revealed that an annual inspection was completed on April 27, 2022 (3 days before the accident), at an aircraft total time (TT) of 11,694.0 hours. The previous annual inspection was completed on January 28, 2021, at 11,680.3 hours TT. A recurring FAA airworthiness directive (AD) 99-11-02, was applicable for this airplane and related to visual inspections to prevent cylinder head cracking. The AD was completed on June 29, 2017, at 11,529.3 hours TT. The AD was due to be completed again 250 hours later, at 11,779.3 hours TT. ## Aircraft - Registration: [N29947](https://openairdocs.org/aircraft/N29947), registered now, S/N 42-85697A, built 1944 (OpenAirDocs) - Reported make and model: NORTH AMERICAN AT-6D - Registry model: [North American AT-6D](https://openairdocs.org/model/north-american-at-6d) (registry code 6400416) (OpenAirDocs) - Registry engine: [Pratt & Whitney R1340 series](https://openairdocs.org/engine/pratt-whitney-r1340-series) (registry code 52016, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 42-85697A - Year built: 1944 - Airframe hours: 11694 - Engines: Pratt & Whitney R-1340-AN 1 600 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Cavanaugh Flight Museum - Registered owner: Cavanaugh Flight Museum - Airworthiness certificate: Standard, Normal - Last inspection: Annual, April 27, 2022 - Destination: Same as departure - Airport: T82, Gillespie County Airport, runway 32, 5,001 × 75 ft, asphalt - Equipment: ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 31; injuries: none; airline transport, flight instructor; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review July 1, 2021; seat: front; restraint: 4-point; flight hours: 4,702 total, 141 in this make and model, 3,778 as pilot in command, 84 in the last 90 days, 30 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 360° at 6 knots - Visibility: 10 statute miles - Lowest ceiling: 6,000 ft broken - Temperature: 82 °F, dew point 64 °F - Altimeter: 29.91 inHg - Observed at: KT82 - METAR: KT82 301815Z AUTO 36006KT 10SM SCT038 BKN060 28/18 A2991 RMK AO2 T02790178 ## 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 20220430005959A](https://openairdocs.org/incident/20220430005959A), Apr 30, 2022: North American AT-6D, Fredericksburg, TX, Substantial damage. On Saturday, March 30, 2022, a North American AT-6D, N29947, s/n: 42-85697A, took off from Gillespie County Airport (T82) at approximately 1300 local with one… ## Other investigations on N29947 (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 NYC83LA048](https://openairdocs.org/ntsb/NYC83LA048), Jan 5, 1983: North American AT-6D (N29947), Granville, PA, destroyed ## Docket (5 files) The files NTSB released with the investigation on March 13, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=105032. 31.6 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16769381&FileExtension=pdf&FileName=6120%20-%20pilot_Redacted-Rel.pdf - NTSB investigation summary (item 2, PDF, 7 pages, 5 photos, 5.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16772533&FileExtension=pdf&FileName=NTSB%20Investigaiton%20summary_Redacted-Rel.pdf - Maintenance records (item 3, PDF, 12 pages, 25.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16769391&FileExtension=pdf&FileName=Maintenance%20records_Redacted-Rel.pdf - Photos (item 4, PDF, 5 pages, 6 photos, 305 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16772600&FileExtension=pdf&FileName=Photos-Rel.pdf - Release of aircraft wreckage, NTSB form 6120.15 (item 5, PDF, 1 page, 43 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16775522&FileExtension=pdf&FileName=NTSB%20Release%20of%20Wreckage%20(signed)_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.