# NTSB ANC99LA082: Maule M-4-220C, N40677, Mcgrath, AK, June 24, 1999 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: June 24, 1999, 12:20 local (20:20 UTC) - Place: Mcgrath, AK - Coordinates: 63.60958, -154.780853 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=63.6096&lon=-154.7809&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report June 23, 2000 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - NTSB case key (mKey): 46654 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC99LA082 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/46654/pdf - Page: https://openairdocs.org/ntsb/ANC99LA082 ## Probable cause A separation of the number 4 engine cylinder, and a fracture of the number 4 engine connecting rod. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(partial) - mech failure/malf, cruise - engine assembly,cylinder - separation (cause) - engine assembly,connecting rod - fractured (cause) - On ground/water collision with object, landing - roll - object - tree(s) - Main gear collapsed, landing - roll ## Analysis The airline transport pilot reported that about 15 minutes after departure, the engine began to run rough, and lose power. He said that while performing the engine emergency procedures, he smelled smoke in the cabin, and he selected a forced landing area on a river bank bordered by trees. During the landing roll, the airplane's left wing collided with a stand of trees, the airplane pivoted 180 degrees to the left, and the left main landing gear collapsed. The airplane sustained substantial damage to the wings, fuselage, and empennage. An FAA airworthiness inspector from the Anchorage Flight Standards District Office, examined the airplane wreckage on June 24th. The inspector reported that the top portion of the number four engine cylinder was separated between the cylinder barrel and the cylinder head, and added that the piston connecting rod was fractured. ## Factual narrative On June 24, 1999, about 1220 Alaska daylight time, a wheel equipped Maule M-4-220C airplane, N40677, sustained substantial damage during a forced landing about 7 miles northeast of McGrath, Alaska. The airplane was being operated as a visual flight rules (VFR) personal flight when the accident occurred. The solo airline transport pilot was not injured. Visual meteorological conditions prevailed, and no flight plan was filed. The flight was the continuation of a cross-country flight that originated at the Willow Airport, Willow, Alaska, about 0930. During a telephone conversation with the National Transportation Safety Board investigator-in-charge on June 24, the pilot reported that his planned destination was Nikolai, Alaska, with a brief stop in Takotna, Alaska. He said that the flight between Willow and Takotna was uneventful. The pilot reported that after takeoff from the Takotna Airport, he climbed the airplane to about 1,500 feet msl. He said that about 15 minutes after departure, the engine began to run rough, and lose power. The pilot said that while performing the engine emergency procedures, he smelled smoke in the cabin, and selected a forced landing area on a river bank bordered by trees. During the landing roll, the airplane's left wing collided with a stand of trees, the airplane pivoted 180 degrees to the left, and the left main landing gear collapsed. The airplane sustained substantial damage to the wings, fuselage, and empennage. The airplane owner recovered and transported the airplane wreckage to the Anchorage International Airport. A Federal Aviation Administration (FAA) airworthiness inspector from the Anchorage Flight Standards District Office, examined the airplane wreckage on July 13th. The inspector reported that the top portion of the number four engine cylinder was separated between the cylinder barrel and the cylinder head, and added that the piston connecting rod was fractured. ## Aircraft - Registration: [N40677](https://openairdocs.org/aircraft/N40677), registered now, S/N 2181C (OpenAirDocs) - Reported make and model: Maule M-4-220C - Registry model: [Maule M-4-220C](https://openairdocs.org/model/maule-m-4-220c) (registry code 5460114) (OpenAirDocs) - Registry engine: [Franklin 6A&6V335 series](https://openairdocs.org/engine/franklin-6a-6v335-series) (registry code 27020, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 2181C - Airframe hours: 2370 - Engines: Franklin 6A-350-C1 220 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Walt Warner - Registered owner: Bonnie L. Warner - Airworthiness certificate: Standard, Normal - Last inspection: Annual, August 31, 1998, 160 hours before - Departed: UUO, WILLOW, AK - Destination: MCG, AK ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 44; flight instructor, airline transport; airplane ratings: multi-engine land, single-engine sea, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 8,500 total, 1,100 in this make and model, 90 in the last 90 days, 30 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 350° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: 7,000 ft broken - Temperature: 68 °F, dew point 54 °F - Altimeter: 29.00 inHg - Observed at: MCG, 7 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 19990624007559A](https://openairdocs.org/incident/19990624007559A), Jun 24, 1999: Maule M4220C, Mcgrath, AK, Substantial damage. Acft crashed while en route and sustained substantial damage, other circumstances are unknown. (From .19) on June 24, 1999, about 1220 Alaska daylight time, a… 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.