# NTSB CHI98LA355: Air Tractor AT-401, N4543F, N. Ottawa Twp., MN, August 28, 1998 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: August 28, 1998, 18:45 local (23:45 UTC) - Place: N. Ottawa Twp., MN - Coordinates: 45.860862, -96.190391 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=45.8609&lon=-96.1904&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report February 16, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 43806 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI98LA355 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/43806/pdf - Page: https://openairdocs.org/ntsb/CHI98LA355 ## Probable cause A loss of engine power due to a worn piston ring. A related factor was the owner exceeded the manufacturer's recommended engine overhaul. ## 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, maneuvering - aerial application - engine assembly,ring - worn - engine assembly,cylinder - low compression - maintenance,overhaul - exceeded, owner/pilot mechanic (contributing factor) - altitude/clearance - low, owner/pilot mechanic (cause) - In flight collision with terrain/water, maneuvering - turn to landing area (emergency) - terrain condition - ground ## Analysis About 5-minutes after the aerial applicator flight had taken off the pilot said, the airplane's engine experienced a partial power loss. He said the airplane '...did not want to climb and began to settle down.' The pilot ejected his chemical load and was maneuvering for a landing when the right wingtip and landing gear struck the ground. The airplane cartwheeled and rolled over the ground before coming to a stop inverted. The on-scene investigation revealed the airplane s engine had 1 cylinder with no compression. Examination showed the piston rings were badly worn and there was no taper to the cylinder. At the time of the accident the engine was about 70-hours beyond the manufacturer's recommended overhaul time. The airplane had received an annual inspection about 4-months before the accident. The engine logbook showed all compression readings were within the manufacturers recommended range. ## Factual narrative On August 28, 1998, at 1845 central daylight time (cdt), an Air Tractor AT-401, N4543F, piloted by a commercial pilot, was destroyed during a collision with the ground while maneuvering for a forced landing. Visual meteorological conditions prevailed at the time of the accident. The 14 CFR Part 137 aerial application flight was not operating on a flight plan. The pilot reported no injuries. The flight departed a restricted landing area near Norcross, Minnesota, at 1840 cdt. The pilot reported a partial loss after completing an aerial application swath run. He said the airplane "...did not want to climb and began to settle down." He said he ejected his chemicals and was maneuvering for the forced landing when the right wing and landing gear struck the ground. According to the pilot, the airplane cartwheeled and rolled over the ground before coming to a stop inverted. The pilot said witnesses at the restricted landing area told him the engine didn't sound normal during the takeoff and climb out. The on-scene investigation revealed the airplane was at gross weight when it had taken off about 5-minutes earlier. An examination of the engine revealed compression on all cylinders except number 4. The Federal Aviation Administration Principal Maintenance Inspector (PMI) who examined the engine said the number 4 cylinder walls and piston rings were badly worn. He said there was no debris on the cylinder's exhaust valve seat or valve face. The PMI said the engine logbooks showed it had been operated 70-hours beyond the manufacturer's recommended TBO. According to the PMI, the engine logbook showed the compression on all the cylinders were within the manufacturer's acceptable range during the April 1998 annual inspection. ## Aircraft - Registration: [N4543F](https://openairdocs.org/deregistered/N4543F-2000-05-11), registration cancelled 2000-05-11, S/N 401-0787 (OpenAirDocs) - Reported make and model: Air Tractor AT-401 - Registry model: [Air Tractor AT-401](https://openairdocs.org/model/air-tractor-at-401) (registry code 0390204) (OpenAirDocs) - Category: Airplane - Serial number: AT 401-0787 - Airframe hours: 2604 - Engines: P&W 1340 600 horsepower reciprocating - Damage: Destroyed - Flight: Aerial application, Part 137 - Registered owner: Carlson Ag Aviation, Inc. - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, April 30, 1998, 750 hours before - Departed: RLA, NORTHFIELD, MN ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 48; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 7,500 total, 1,000 in this make and model, 300 in the last 90 days, 150 in the last 30 days, 8 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 360° at 9 knots - Visibility: 10 statute miles - Temperature: 82 °F, dew point 63 °F - Altimeter: 29.00 inHg - Observed at: AXN, 33 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 19980828022369A](https://openairdocs.org/incident/19980828022369A), Aug 28, 1998: Airtrc AT401, Ottowa Twnsp, MN, Destroyed. On August 28, 1998, at 1845 central daylight time, an air tractor AT-401, N4543F, piloted by a commercial pilot, was destroyed during a collision with the… ## Other investigations on N4543F (1) 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. - [NTSB CHI95LA258](https://openairdocs.org/ntsb/CHI95LA258), Aug 4, 1995: Air Tractor AT-401 (N4543F), Aurora, NE, substantial damage. Probable cause: the cracked engine assembly that caused the power loss during a critical phase of flight. Factors associated with this accident were the restricted airplane performance due to the power loss, the… 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.