# NTSB CEN12LA530: Williams John T-51 Mustang, N151TA, Oshkosh, WI, August 7, 2012 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: August 7, 2012, 16:20 local (21:20 UTC) - Place: Oshkosh, WI - Coordinates: 43.985, -88.561668 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=43.9850&lon=-88.5617&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed, report February 27, 2013 - Report: Approved by Office Director - NTSB office: Central Region - Parties: Federal Aviation Administration, FAA Flight Standards District Office - NTSB case key (mKey): 84610 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN12LA530 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/84610/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=84610 - Page: https://openairdocs.org/ntsb/CEN12LA530 ## Probable cause The separation of an engine cooling hose from the radiator. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Aircraft](https://openairdocs.org/ntsb-findings/01020000): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [Williams John T-51 MUSTANG, 1 case](https://openairdocs.org/ntsb-findings/01020000/cases.md?model=05622SJ), [All aircraft, 63 cases](https://openairdocs.org/ntsb-findings/01020000/cases.md) - [Maintenance](https://openairdocs.org/ntsb-findings/02062000): Personnel issues › Task performance · Not specified; cases with it: [Williams John T-51 MUSTANG, 1 case](https://openairdocs.org/ntsb-findings/02062000/cases.md?model=05622SJ), [All aircraft, 143 cases](https://openairdocs.org/ntsb-findings/02062000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Prior to flight: Aircraft maintenance event](https://openairdocs.org/ntsb-events/040); cases with it: [Williams John T-51 MUSTANG, 1 case](https://openairdocs.org/ntsb-events/040/sequence.md?model=05622SJ), [All aircraft, 484 cases](https://openairdocs.org/ntsb-events/040/sequence.md) - [Landing: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340); cases with it: [Williams John T-51 MUSTANG, 1 case](https://openairdocs.org/ntsb-events/340/sequence.md?model=05622SJ), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md) - [Initial climb: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Williams John T-51 MUSTANG, 1 case](https://openairdocs.org/ntsb-events/342/sequence.md?model=05622SJ), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Landing: Fire/smoke (non-impact)](https://openairdocs.org/ntsb-events/150); cases with it: [Williams John T-51 MUSTANG, 1 case](https://openairdocs.org/ntsb-events/150/sequence.md?model=05622SJ), [All aircraft, 504 cases](https://openairdocs.org/ntsb-events/150/sequence.md) - [Landing-flare/touchdown: Landing gear collapse](https://openairdocs.org/ntsb-events/094); cases with it: [Williams John T-51 MUSTANG, 1 case](https://openairdocs.org/ntsb-events/094/sequence.md?model=05622SJ), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) ## Analysis Shortly after takeoff for a test flight, the pilot noticed that the airplane was not climbing as expected and the engine was slowly losing power. The coolant temperature was 225 degrees and the airplane was only 250 to 300 feet above ground level. During the return to the airport, the pilot heard and felt an explosion behind him and felt a burning sensation on his back. During the forced landing, the right main landing gear collapsed. Examination of the airplane revealed that a cooling line had separated from the radiator behind the pilot during the accident flight. The examination also revealed that the radiator hose line clamp for a different cooling hose was overtightened and not seated properly in its pipe bead. A replacement engine had been installed as a result of a blown head gasket during a previous flight; however, the cooling system was not replaced, and it could not be determined when the clamp was overtightened. An examination of the remaining systems revealed no anomalies. ## Factual narrative On August 7, 2012, about 1620 central daylight time a Williams T-51 Mustang airplane, N151TA, conducted a forced landing at the Wittman Regional Airport (KOSH), Oshkosh, Wisconsin. The commercial pilot was seriously injured and the airplane was substantially damaged. The airplane was registered to and operated by a private individual under the provisions of 14 Code of Federal Regulations Part 91 as a test flight. Visual meteorological conditions prevailed for the flight which operated without a visual flight rules flight plan. The local flight was originating at the time of the accident. According to the pilot, the purpose of the test flight was to trouble-shoot the lower engine power and higher than expected operating temperatures encountered during the previous test flight. After takeoff, the airplane was not performing as expected and the engine was slowly losing power. The pilot observed that the coolant temperature was 225 degrees and the airplane was only 250 to 300 feet above ground level. The pilot communicated with air traffic control that he wanted to return to the airport and started a turn. During the turn, the pilot heard and felt an explosion behind him and felt a burning sensation on his back. The pilot lost all forward visibility as the windscreen was black with smoke, but he was able to see a small amount out the left side of the windscreen. The pilot stated that he continued to try and fly the airplane, though he was limited by the inability to see outside of the airplane and the pain associated with the burning sensation on the left side of his body. The pilot extended the landing gear and conducted a forced landing in the grass, just short of the general aviation ramp. According to the Federal Aviation Administration (FAA) inspector who traveled to the accident scene, the right main landing gear collapsed during the forced landing. The airplane continued an additional 300 feet before coming to rest. The left wing and left flap were wrinkled during the forced landing. The airplane was recovered and relocated to the owner’s hangar in Ohio for further examination. The FAA inspector who provided oversight for the examination reported that there were no negative properties or operational failures observed during the testing of the cooling system. The number four spark plug was severely damaged. According to the pilot, an examination of the engine revealed no further anomalies. The pilot added that a cooling hose separated from the radiator which was located behind him. The radiator and cooling lines had not been boxed in, which would isolate the cooling system from the cockpit. Several days prior to the accident flight, the engine and cooling system operated at a higher than normal power setting and coolant temperature. After the flight, the coolant temperature reached the maximum range of 250 degrees Fahrenheit and coolant purged itself from the system. On a subsequent flight, the coolant temperature gauge did not function andshortly after takeoff the pilot observed smoke in the cockpit. As the pilot returned to the airport to land, he noticed that the engine oil temperature was high and the oil pressure was low. An examination revealed an oil leak between the cylinder head and the engine block. Following this flight, a replacement engine was installed; however, the cooling system was not replaced. ## Aircraft - Registration: [N151TA](https://openairdocs.org/aircraft/N151TA), registered now, S/N M04SV6SOHK0027, built 2004 (OpenAirDocs) - Reported make and model: WILLIAMS JOHN T-51 MUSTANG - Registry model: [Williams John T-51 MUSTANG](https://openairdocs.org/model/williams-john-t-51-mustang) (registry code 05622SJ) (OpenAirDocs) - Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: M04SV6SOHK0027 - Engines: Honda J35A6 245 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Condition, March 24, 2012 - Departed: KOSH, Oshkosh, WI - Destination: KOSH, Oshkosh, WI - Airport: KOSH, Wittman Regional Airport, runway 09, 6,179 × 150 ft ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 63; injuries: serious; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review August 12, 2011; seat: front; flight hours: 6,918 total, 850 in this make and model, 6,750 as pilot in command, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 60° at 10 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 84 °F, dew point 64 °F - Altimeter: 29.90 inHg - Observed at: KOSH, 1 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 20120807017679A](https://openairdocs.org/incident/20120807017679A), Aug 7, 2012: Williams John T-51 MUSTANG, Oshkosh, WI, Substantial damage. N151TA departed runway 9. Shortly after departure, N151TA reported a problem and requested a 180 degree turn to land runway 27. The cockpit filled with steam… ## Docket (4 files) The files NTSB released with the investigation on January 16, 2013, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=84610. 2.6 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 783 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40384097&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Record of Telephone Conversation - FAA (item 2, .PDF, 24 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40384444&FileExtension=.PDF&FileName=Record%20of%20Telephone%20Conversation%20-%20FAA-Master.PDF - FAA Test Report - CEN12LA530 (item 3, .PDF, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40384098&FileExtension=.PDF&FileName=FAA%20Test%20Report%20-%20CEN12LA530-Master.PDF - T-51 Hose Clamp Advisory (item 4, .PDF, 173 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40384442&FileExtension=.PDF&FileName=T-51%20Hose%20Clamp%20Advisory-Master.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.