# NTSB CEN09LA490: Grumman American AA-1B, N1644R, Whitney, TX, August 3, 2009 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: August 3, 2009, 10:00 local (15:00 UTC) - Place: Whitney, TX - Coordinates: 30.924444, -97.356109 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=30.9244&lon=-97.3561&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report December 15, 2009 - Report: Approved by Office Director - NTSB office: Central Region - Parties: Federal Aviation Administration, Lycoming Engines - NTSB case key (mKey): 74440 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN09LA490 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/74440/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=74440 - Page: https://openairdocs.org/ntsb/CEN09LA490 ## Probable cause A partial loss of engine power for undetermined reasons. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Grumman American Avn. AA-1B, 3 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=3960103), [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. - [Takeoff: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Grumman American Avn. AA-1B, 4 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=3960103), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Emergency descent: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342); cases with it: [Grumman American Avn. AA-1B, 4 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=3960103), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Landing-landing roll: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Grumman American Avn. AA-1B, 5 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=3960103), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md) ## Analysis After an hour's flight, including touch and go maneuvers, the pilot landed, added 10.9 gallons of fuel, and departed the airport. After a time of sightseeing, he landed at the accident airport, back-taxied and performed a magneto check before departing. Shortly after takeoff the engine began to run rough as if it had a fouled plug. While turning to downwind the engine began to shake violently and the rpms and altitude were decreasing. The pilot selected a field and performed a soft-field landing. During the landing rollout the airplane nosed over and came to rest in an inverted position. The pilot was able to exit the airplane unassisted. Moments later the airplane was engulfed in flames. A thorough examination of the engine following the accident was performed. The reason for the reported partial loss of engine power could not be determined. ## Factual narrative On August 3, 2009, about 1000 central daylight time, a single-engine Grumman American AA-1B airplane, N1644R, was substantially damaged during a forced landing following a loss of engine power after takeoff from the Lake Whitney State Park Airport (F50), Whitney, Texas. The airline transport pilot, the sole occupant, sustained minor injuries. The airplane was registered to and operated by the pilot. Visual meteorological conditions prevailed and no flight plan was filed for the 14 Code of Federal Regulations Part 91 personal flight. The flight was originating at the time of the accident and was destined for the Clifton Municipal Airport (7F7), near Clifton, Texas. According to the pilot, following an hour's flight including touch and go maneuvers, he landed at 7F7, added 10.9 gallons of fuel, and departed the airport. After a time of sightseeing, he landed at F50, back taxied, and performed a magneto check before departing. Shortly after takeoff the engine began to "run rough as if it had a fouled plug." While turning to downwind the engine began to "shake violently" and the RPM and altitude were decreasing. The pilot selected a field and performed a soft field landing. During the landing rollout the airplane nosed over and came to rest in an inverted position. The pilot was able to exit the airplane unassisted. Moments later the airplane was engulfed in flames. The engine, with 67 hours since major overhaul, was separated from the airframe and placed on a bench. The upper spark plugs and valve covers were removed. Investigators manually rotated the engine via the vacuum pump drive. Valve train continuity was established to each cylinder and to the oil pump. Thumb compression was developed in each cylinder. The cylinders were examined via a borescope and all of cylinder domes and piston heads exhibited "normal" deposits. Each intake and exhaust valve was found in their respective positions. Both magnetos were removed and examined. The left magneto was placed on a test bench and produced spark to all four leads. The right magneto initially produced spark to all four leads and then stopped. An examination inside the right magneto revealed thermal damage as a result of the post impact fire. The spark plugs exhibited normal wear when compared to the Champion Check-A-Plug comparison card. The exception was the number 3 lower spark plug that had sustained impact damage. In addition, the number 2 and 4 lower spark plugs were oil soaked. The carburetor exhibited impact damaged to the mounting flange. The carburetor fuel inlet screen was removed and found to be clean and unobstructed. The unit was disassembled and examined. No post accident anomalies were noted. ## Aircraft - Registration: [N1644R](https://openairdocs.org/deregistered/N1644R-2010-02-11), registration cancelled 2010-02-11, S/N AA1B0644, built 1976 (OpenAirDocs) - Reported make and model: GRUMMAN AMERICAN AA-1B - Registry model: [Grumman American Avn. AA-1B](https://openairdocs.org/model/grumman-american-avn-aa-1b) (registry code 3960103) (OpenAirDocs) - Registry engine: [Lycoming 0-235 series](https://openairdocs.org/engine/lycoming-0-235-series) (registry code 41505, 4 cycle) (OpenAirDocs) - Category: Airplane - Serial number: AA1B0644 - Airframe hours: 2425 - Engines: LYCOMING O-235 SERIES 115 horsepower reciprocating - Damage: Substantial damage - Fire: On-Ground - Flight: Personal, Part 91 - Operator: Wroten Jonathan D - Registered owner: Wroten Jonathan D - Airworthiness certificate: Standard, Normal - Last inspection: Annual, June 4, 2009 - Departed: F50, Whitney, TX - Destination: 7F7, Clifton, TX - Airport: F50, Lake Whitney State Park, runway 17, 2,000 × 50 ft ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 56; injuries: minor; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: helicopter, airplane; medical: class 1, with waivers/limitations; last flight review December 14, 2008; seat: left; flight hours: 17,722 total, 1,150 in this make and model, 15,014 as pilot in command, 25 in the last 90 days, 6 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 180° at 10 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 180 °F - Observed at: INJ, 17 nm away ## 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 20090803012189A](https://openairdocs.org/incident/20090803012189A), Aug 3, 2009: Amrgen AA1B, Whitney, TX, Destroyed. (-23) On August 03, 2009 N1644R, Grumman AA1B departed lake Whitney airport, F50 for a routine flight at 1015 hours. Right after takeoff the engine started to… ## Docket (2 files) The files NTSB released with the investigation on September 29, 2009, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=74440. 613 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 504 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40318564&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Statement of Party Representatives to NTSB Investigation (item 2, .PDF, 109 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40319100&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-Redacted.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.