# NTSB NYC94LA174: Piper PA-24-250, N55GV, North Anson, ME, September 10, 1994 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: September 10, 1994, 13:00 local (17:00 UTC) - Place: North Anson, ME - Location: 44.8639° N, 69.8990° W: Placed by OpenAirDocs: center of North Anson, ME, within about 6 miles (OpenAirDocs) - Nearby events: https://openairdocs.org/map.md?lat=44.8639&lon=-69.8990&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 2 minor - Status: Completed, report January 26, 1995 - Report: Approved by Office Director - NTSB case key (mKey): 38829 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC94LA174 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/38829/pdf - Page: https://openairdocs.org/ntsb/NYC94LA174 ## Probable cause the inadequately installed cylinder mounting stud nuts, by the engine overhaul facility, which resulted in the separation of the number two cylinder and the subsequent forced landing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(total) - mech failure/malf, cruise - engine assembly,cylinder - separation - maintenance,overhaul,major - inadequate, other maintenance personnel (cause) - Forced landing, descent - emergency - On ground/water collision with object, landing - object - tree(s) ## Analysis THE PILOT AND PASSENGER WERE ON THE SECOND LEG OF A CROSS COUNTRY FLIGHT. THIRTY MINUTES INTO THE FLIGHT A VIBRATION BEGAN, FOLLOWED BY OIL SEEPING FROM THE ENGINE COWLING. A FEW SECONDS LATER THE ENGINE FAILED AND OIL COVERED THE AIRPLANE WINDSHIELD. THE PILOT PERFORMED A FORCED LANDING TO AN OPEN FIELD WITH NO FORWARD VISIBILITY DUE TO THE OIL. THE PILOT WAS UNABLE TO STOP THE AIRPLANE BEFORE IT STRUCK TREES AT THE END OF THE FIELD. EXAMINATION REVEALED THAT THE NUMBER TWO CYLINDER HAD SEPARATED FROM THE ENGINE. SEVEN OF THE EIGHT CYLINDER STUDS HAD SHEARED. THE STUD NOT SHEARED WAS INTACT AND UNDAMAGED. AN UPPER STUD WAS RUSTED PARTIALLY ACROSS, WITH THE REMAINDER OF THE STUD SHEARED CLEANLY. THE ENGINE HAD BEEN OVERHAULED 362 TACH HOURS BEFORE THE FAILURE BY A LOCAL ENGINE OVERHAUL FACILITY. ## Factual narrative On September 10, 1994, at 1300 eastern daylight time, a Piper PA-24-250, N55GV, owned by O&A Aircraft Modifications, Inc., and piloted by Joseph S. Grabin, was substantially damaged during a forced landing to an open field near North Anson, Maine. The pilot and passenger were not injured. Visual meteorological conditions prevailed, and no flight plan had been filed for the flight operating under 14 CFR Part 91. This was the second leg of a cross country flight that originated in Factoryville, Pennsylvania, the same day. Mr. Grabin and his passenger departed the Oxford County Regional Airport, Oxford, Maine, at approximately 1230 for the last leg to Greenville, Maine. In the NTSB Form 6120.1/2, the pilot stated: "...thirty minutes into the flight a vibration began in the engine. A few seconds later I noticed a small bit of oil seeping up at the rear of the cowling. I turned direct to Central Maine Airport. Thirty seconds or so later, more oil came out and covered half of the window. A few seconds later the engine let go followed by more oil in the slip stream, which completely covered the windshield...looking out the side window I turned sharp and slipped into the field with no forward visibility. Touched down was good, but I was unable to stop before the end, and went into the trees." In the Federal Aviation Administration (FAA) Inspector's report, he stated that an inspection of the engine revealed that the number two cylinder had separated from the engine case. The top of the cylinder did not show any evidence of damage, except where it had punctured the left hand engine cowl. He further stated: "...All damage appeared to be the result of the cylinder separating from the case. Seven of the eight cylinder mounting studs were sheared off, while the eighth stud (lower forward position) was intact...the absence of paint on this stud's threads would indicate that the nut had been originally installed when the engine was painted during overhaul...the #2 cylinder lower side of the mounting flange and the corresponding case surface showed evidence of fretting...the initial evidence indicated an undertorque situation which could have propagated into the loss of the lower forward stud mount nut. This may have resulted in the failure of the upper forward mount stud over a period of time as suggested by the rusting found on this stud...With the failure of this stud and lack of holding power from the lower forward stud, the stress on the remaining studs conceivably would cause their failure..." The engine was installed on November 2, 1990. It had been overhauled by a company no longer in business, the Windham Aircraft Engines, Inc., of Willimantic, Connecticut. The engine had accumulated approximately 362 hours since installation. ## Aircraft - Registration: [N55GV](https://openairdocs.org/deregistered/N55GV-1995-01-30), registration cancelled 1995-01-30, S/N 24401 (OpenAirDocs) - Reported make and model: PIPER PA-24-250 - Registry model: [Piper PA-24-250](https://openairdocs.org/model/piper-pa-24-250) (registry code 7102404) (OpenAirDocs) - Category: Airplane - Serial number: 24-401 - Airframe hours: 3218 - Engines: LYCOMING O-540-A1A5 250 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: O & N Aircraft Modifications - Airworthiness certificate: Standard, Normal - Last inspection: Annual, May 1, 1994, 51 hours before - Departed: 81B, OXFORD, ME - Destination: 3B1, GREENVILLE, ME ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 42; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 2,808 total, 3 in this make and model, 1,470 as pilot in command, 19 in the last 90 days, 5 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 260° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: 4,600 ft broken - Temperature: 59 °F, dew point 43 °F - Altimeter: 29.00 inHg - Observed at: WVL, 21 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 19940910026179A](https://openairdocs.org/incident/19940910026179A), Sep 10, 1994: Piper PA24250, North Anson, ME, Substantial damage. Vibration. Oil covered windshield. Landed blind into field and trees. NR2 cylinder separated. Under torqued studs. 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.