# NTSB DFW05IA048: Beech A36, N920GL, Natchitoches, LA, December 29, 2004 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: December 29, 2004, 17:35 local (23:35 UTC) - Place: Natchitoches, LA - Coordinates: 31.735555, -93.098892 - Nearby events: https://openairdocs.org/map.md?lat=31.7356&lon=-93.0989&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 4 uninjured - Status: Completed, report June 28, 2006 - Report: Approved by Office Director - Parties: National Transportation Safety Board, Teledyne Continental Motors, FAA-Flight Standards District Office - NTSB case key (mKey): 60784 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DFW05IA048 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/60784/pdf - Page: https://openairdocs.org/ntsb/DFW05IA048 ## Probable cause The loss of engine power due to pre-ignition and detonation. Contributing factors were the lack of suitable terrain available for the forced landing and the unapproved installation of a turbocharger. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power, cruise - normal - maintenance,installation - not approved, unknown (contributing factor) - exhaust system,turbocharger - unapproved (contributing factor) - misc,engine pre-ignition and/or detonation - overtemperature (cause) - fluid,oil - exhaustion - Forced landing, emergency descent/landing - In flight collision with terrain/water, emergency landing - terrain condition - none suitable (contributing factor) ## Analysis The 15,000-hour commercial pilot reported that while he was in cruise flight at 12,000 feet mean sea level (msl) during an IFR cross country flight, he began to smell smoke and noticed the engine began to surge. After requesting a lower altitude, the air traffic controller advised him of the nearest airport. During the descent, at an altitude of approximately 9,000 feet msl, "the engine lost oil pressure" and the pilot shut the engine down using the mixture control. The "engine continued to turn over" as he heard "several loud explosions and observed fireballs at the propeller hub" before the propeller stopped turning. After realizing he was unable to make it to the airport, the pilot elected to land in a field approximately 1/2 mile south of his intended airport. After maneuvering the airplane under a set of power lines, the pilot landed in an open field. A detailed examination of the engine was completed at the facilities of the engine manufacturer. The examination revealed that the crankshaft and counterweights assembly exhibited lubrication distress of a varying degree to all connecting rod journals and bearings. The number six piston head exhibited detonation and pre-ignition damage. The examination concluded that a turbo-normalizing system had been installed and the installation of a turbo-normalizing system on an engine originally certificated as a normally aspirated model containing high compression pistons is contrary to the recommendations in TCM Service Bulletin M64-18 and can reduce the engine's detonation margins. ## Factual narrative On December 29, 2004, approximately 1735 central standard time, a single-engine Beech A36 airplane, N920GL, sustained minor damage during a forced landing following a partial loss of engine power near the Natchitoches Regional Airport (IER), near Natchitoches, Louisiana. The commercial pilot and three passengers were not injured. The airplane was registered to a private individual and operated by the pilot. Dusk visual meteorological conditions prevailed, and a instrument flight rules (IFR) flight plan was filed for the 14 Code of Federal Regulations Part 91 personal flight. The cross-country flight originated from the Diamondhead Airport, near Diamondhead, Mississippi, at an unknown time, and was destined for the Center Municipal Airport, near Center, Texas. In a written statement, the pilot reported that while in cruise flight, while assigned at 12,000 feet mean sea level (msl) while on an IFR cross-country flight, he began to smell smoke and noticed the engine began to surge. After requesting a lower altitude, the air traffic controller advised him of the nearest airport. During the descent, at an altitude of approximately 9,000 feet msl, "the engine lost oil pressure" and the pilot shut the engine down using the mixture control. The "engine continued to turn over" as he heard "several loud explosions and observed fireballs at the propeller hub" before the propeller stopped turning. After realizing he was unable to make it to the airport, the pilot elected to land in a field approximately 1/2 mile south of IER. After maneuvering the airplane underneath a set of power lines, the pilot landed in an open field. During the landing roll, the nose gear collapsed and the airplane came to rest upright in a nose low position in a muddy field. A visual examination of the engine by the pilot revealed that there was a hole in the crankcase near the number two cylinder. The 1993-model Bechcraft A36, a low wing six-place airplane, serial number E-2776, was powered by a single Continental IO-550-B engine, rated at 300 horsepower. On December 7, 2005, an examination of the engine was conducted under the supervision of an NTSB investigator at Teledyne Continental Motors, Inc., near Mobile, Alabama. The examination revealed that the engine contained aftermarket parts and components indicating that the engine had been field overhauled. A turbo-normalizing system had also been installed. The crankshaft and counterweight assembly exhibited lubrication distress of varying degrees to all connecting rod journals and bearings. The most severe thermal and mechanical damage was concentrated at the number three connecting rod and journal. The number six piston head exhibited detonation/preignition damage causing the erosion of the piston head edge and approximately twenty-five percent of the radius at exhaust side, torching through and beneath the top ring steel insert and progressing through the remaining rings and lands to the interior. This piston damage would allow excessive by-pass of combustion gases, creating extremely high crankcase pressure, with subsequent oil loss through the crankcase breather system. The installation of a turbo-normalizing system on an engine originally certificated as a naturally aspirated model containing high compression pistons is contrary to the recommendations in TCM Service Bulletin M64-18 and can reduce the engine’s detonation margins. The engine and airframe logbooks were not available for review during the course of the accident investigation. ## Aircraft - Registration: N920GL (not matched to a registry record) - Reported make and model: Beech A36 - Category: Airplane - Serial number: E-2776 - Engines: Continental IO-550-B 300 horsepower reciprocating - Damage: Minor damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Departed: 66Y, Diamondhead, MS - Destination: F17, Center, TX - Flight plan: IFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 51; injuries: none; airline transport, flight engineer, commercial, flight instructor; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; last flight review November 1, 2004; seat: left; flight hours: 15,000 total, 200 in this make and model, 10,000 as pilot in command, 75 in the last 90 days, 45 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 150° at 4 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 66 °F, dew point 48 °F - Altimeter: 30.27 inHg ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Incident 20041229033389I](https://openairdocs.org/incident/20041229033389I), Dec 29, 2004: Beech A36, Minor damage. (-23) On December 17, 2004, at 1735 CST a Beechcraft, model A-36, N920GL, while in cruise flight experienced a rough running engine followed by loss of oil… 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.