# NTSB CHI01LA135: Air Tractor AT-401, N1008Q, Warsaw, IL, May 12, 2001 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 12, 2001, 10:30 local (15:30 UTC) - Place: Warsaw, IL - Coordinates: 40.34909, -91.419647 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=40.3491&lon=-91.4196&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report August 21, 2001 - Report: Approved by Office Director - Parties: Federal Aviation Administration - NTSB case key (mKey): 52277 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI01LA135 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/52277/pdf - Page: https://openairdocs.org/ntsb/CHI01LA135 ## Probable cause the rocker assembly failure during low level maneuvering. Factors were the soft and sandy terrain and the unsuitable terrain the pilot encountered during the 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, maneuvering - aerial application - engine assembly,rocker arm/tappet - failure (cause) - Forced landing, emergency descent/landing - Nose over, emergency descent/landing - terrain condition - soft (contributing factor) - unsuitable terrain or takeoff/landing/taxi area - encountered, pilot in command (contributing factor) ## Analysis The airplane sustained substantial damage when the airplane nosed over during a forced landing following an in-flight loss of engine power. The pilot reported no injuries. The pilot stated, "At approximately 10:30 AM spraying operation was nearing completion when in a pull out of the field being sprayed the engine made a bang, started running very rough and backfiring. Within a couple seconds the engine had lost all power and died. The pilot landed in a field that happened to be very soft and sandy. The aircraft rolled approximately 100 ft on its wheels before nosing over on its back. After further investigation it was determined a rocker shaft housing had broken on the #4 cylinder. As a result the exhaust valve was not opening. As the intake valve opened, it created backfiring into the induction system causing the engine to fail." ## Factual narrative On May 12, 2001, about 1030 central daylight time, an Air Tractor AT-401, N1008Q, piloted by a commercial pilot, sustained substantial damage when it nosed over during a forced landing following an in-flight loss of engine power while maneuvering near Warsaw, Illinois. The aerial application flight was operating under 14 CFR Part 137. Visual meteorological conditions prevailed at the time of the accident. No flight plan was on file. The pilot reported no injuries. The local flight departed from an airstrip, near Ferris, Illinois, about 0945. The pilot stated, "At approximately 10:30 AM spraying operation was nearing completion when in a pull out of the field being sprayed the engine made a bang, started running very rough and backfiring. Within a couple seconds the engine had lost all power and died. The pilot landed in a field that happened to be very soft and sandy. The aircraft rolled approximately 100 ft on its wheels before nosing over on its back. After further investigation it was determined a rocker shaft housing had broken on the #4 cylinder. As a result the exhaust valve was not opening. As the intake valve opened, it created backfiring into the induction system causing the engine to fail." ## Aircraft - Registration: [N1008Q](https://openairdocs.org/aircraft/N1008Q), registered now, S/N 401-0702, built 1988 (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) - Registry engine: [Pratt & Whitney R1340 series](https://openairdocs.org/engine/pratt-whitney-r1340-series) (registry code 52016, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 401-0702 - Airframe hours: 3648 - Engines: P&W R-1340 600 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Registered owner: Charles H. Holzwarth - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, March 13, 2001, 10 hours before - Departed: Ferris, IL ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 43; injuries: none; flight instructor, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; last flight review July 15, 1999; seat: center; flight hours: 4,320 total, 130 in this make and model, 4,320 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: 350° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 61 °F, dew point 48 °F - Altimeter: 30.31 inHg - Observed at: EOK, 10 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 20010512011019A](https://openairdocs.org/incident/20010512011019A), May 12, 2001: Airtrc AT401, Warsaw, IL, No damage. (.19)On may 12, 2001, about 1045 central daylight time, an air tractor AT-401, N1008Q, piloted by a commercial pilot, sustained substantial damage on impact… 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.