# NTSB CHI03LA095: Air Tractor AT-401, N45297, Knox, IN, March 31, 2003 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: March 31, 2003, 14:40 local (19:40 UTC) - Place: Knox, IN - Coordinates: 41.189723, -86.606941 - Nearby events: https://openairdocs.org/map.md?lat=41.1897&lon=-86.6069&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed, report July 29, 2004 - Report: Approved by Office Director - Parties: FAA -- South Bend FSDO - NTSB case key (mKey): 56809 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI03LA095 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/56809/pdf - Page: https://openairdocs.org/ntsb/CHI03LA095 ## Probable cause A loss of engine power due to oil starvation as a result of the failure of the master rod bearing. Contributing factors were the tree line at the edge of the field, and the unsuitable terrain. ## 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 - fluid,oil - starvation (cause) - engine assembly,bearing - failure (cause) - Forced landing, emergency descent/landing - In flight collision with terrain/water, emergency landing - unsuitable terrain or takeoff/landing/taxi area - encountered, pilot in command (cause) - terrain condition - ground - Nose over, emergency descent/landing ## Analysis The aircraft was substantially damaged during a forced landing following an engine failure. The pilot reported that a newly overhauled engine had recently been installed on the aircraft. Several ground test runs had been completed with no problems noted. Immediately prior to the accident flight, the pilot stated that the engine was warmed up and the oil temperature was within takeoff limits. He reported that he departed uneventfully and climbed to 400 feet above ground level. He noted that the oil temperature rose to 180 - 200 degrees before dropping back to 135 degrees, indicating the oil was being circulated through the oil cooler. About five miles south of the departure airport the pilot noted a drop in oil pressure and decided to divert to an intermediate airport. The oil pressure continued to drop and the engine started losing power. The aircraft was not able to maintain altitude at this point. The pilot estimated that he was not going to be able to clear a line of trees adjacent to the intermediate airport. He selected and made a forced landing in a field short of the airport. He stated that he touched down in the field "all right," but to avoid hitting trees at the end of the field, he applied the brakes causing the aircraft to flip over. The aircraft came to rest inverted at the edge of a harvested soybean field. An on-scene inspection revealed that three cylinder heads had failed. The lower fuselage was covered in oil emanating in a fan-shaped pattern from the engine oil breather tube and extending to the tail of the aircraft. An engine teardown was performed. The master rod bearing was deformed and had extruded from the rod. It appeared to have a bluish tint consistent with overheating of the material. The oil pump would not rotate under hand pressure. The drive gear, housing and attachments appeared undamaged. The oil check valve was free to move. Upon disassembly, the oil pump gears appeared undamaged. Scrape marks were observed on the interior of the pump housing. At the oil pump inlet a small piece of rubber hose was recovered. The engine fittings were not capped when the NTSB arrived for the teardown. ## Factual narrative On March 31, 2003, at 1440 eastern standard time, an Air Tractor AT-401, N45297, piloted by a commercial pilot, was substantially damaged during a forced landing following an engine failure near Knox, Indiana. Visual meteorological conditions prevailed at the time. The maintenance test flight was operating under the provisions of 14 CFR Part 91 and was not on a flight plan. The pilot sustained serious injuries. The aircraft departed the Starke County Airport (OXI), Knox, Indiana, approximately 1425. The intended destination was Arens Field Airport (RWN), Winamac, Indiana. In his written statement, the pilot reported that in the weeks prior to the accident flight a newly overhauled engine had been installed on the aircraft. Several engine test runs were conducted with no oil leaks or other anomalies noted. The pilot stated that immediately prior to the accident flight, the engine was warmed up for about 20 minutes prior to taxiing for departure. He noted the run-up was normal and the oil temperature was within the green arc prior to initiating the takeoff. The pilot reported that the takeoff was uneventful and he climbed to 400 feet above ground level before proceeding to the south. The pilot reported that the oil temperature rose to 180 - 200 degrees before dropping back to 135 degrees, indicating the oil was being circulated through the oil cooler. The oil pressure was "good" throughout the time. He stated that about two miles south of the airport the oil temperature and pressure indicated 135 degrees and 80 lbs., respectively. Approximately 5 miles from the airport the oil pressure had decreased to about 40 lbs. At this point, the pilot decided to divert toward Wheeler Airport (3C5), which was approximately 2 miles east of the aircraft's position. The pilot stated that when he was established on an easterly heading he noted the oil pressure had dropped to 25 lbs. The engine was losing power at this point and the aircraft was not able to maintain altitude. The pilot estimated that he was not going to be able to clear a line of trees along the west end of 3C5. He selected and made a forced landing in a field short of the airport. He stated that he touched down in the field "all right," but to avoid hitting trees at the end of the field, he applied the brakes causing the aircraft to flip over. The aircraft came to rest inverted at the edge of a harvested soybean field. Federal Aviation Administration inspectors conducted an on-scene inspection. Three cylinder heads had failed. The lower fuselage was covered in oil emanating in a fan-shaped pattern from the engine oil breather tube and extending to the tail of the aircraft. There were no other signs of oil leakage. No oil appeared to remain in the oil tank. The oil screen was free of debris and contamination. The engine was removed and subsequently torn down under NTSB supervision. The number 1 cylinder head had failed completely. The number 2 cylinder head was cracked. The number 8 cylinder was missing approximately 1-1/2 inches of the lower portion of the cylinder head. The threads of the cylinder body were completely exposed. The right magneto was cracked at the base, separating the unit from its mount. The magneto drive gear appeared intact. The ignition leads were secure and the points appeared undamaged. The left magneto was intact and securely attached to the engine. The oil pump would not rotate under hand pressure. The drive gear, housing and attachments appeared undamaged. The internal cover safety wire was intact. The oil check valve was free to move. Upon disassembly, the oil pump gears appeared undamaged. Scrape marks were observed on the interior of the pump housing. At the oil pump inlet a small piece of rubber hose was recovered. The piece measured 1-1/2 inches by 3/8 inch by 1/8 inch thick. The housing inlet cavity measured approximately 7/8 inch wide by 3/4 inch deep. A 15/16 inch diameter, 45-degree angled tube was installed outside the cavity inlet to provide an installation flange for the oil hose. The engine fittings were not capped when the NTSB arrived for the teardown. The master rod bearing was deformed and had extruded from the rod. It appeared to have a bluish tint consistent with overheating of the material. The newly overhauled Pratt & Whitney R-1340-59 radial engine, serial number 41-12095, was installed on the airframe on March 25, 2003. Total engine time was recorded as 5,283.9 hours. This was the first flight since the overhauled engine had been installed. The logs and the pilot's statement stated that the engine had undergone ground runs to verify the installation. They stated that no leaks were observed following those runs. The overhaul was conducted by Tulsa Aircraft Engines under work order 3926. According to documentation from the overhaul shop, the engine was test run for 4 hours on February 18, 2003, prior to shipment for installation. ## Aircraft - Registration: [N45297](https://openairdocs.org/deregistered/N45297-2015-07-17), registration cancelled 2015-07-17, S/N 401-0760 (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: 401-0760 - Airframe hours: 3948 - Engines: Pratt & Whitney R-1340 600 horsepower reciprocating - Damage: Substantial damage - Fire: On-Ground - Flight: Flight test, Part 91 - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, May 14, 2002, 195 hours before - Departed: OXI, Knox, IN - Destination: RWN, Winamac, IN - Airport: 3C5, Wheeler ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 50; injuries: serious; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; last flight review April 16, 2002; seat: single; flight hours: 10,072 total, 800 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 200° at 13 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 52 °F, dew point 21 °F - Altimeter: 30.04 inHg - Observed at: VPZ, 23 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 20030331005589A](https://openairdocs.org/incident/20030331005589A), Mar 31, 2003: Airtrc AT401, Knox, IN, Substantial damage. (-23) Pilot was flight testing aircraft after new engine was installed. Pilot reported loss of oil pressure and engine power. A/c landed in corn field and… ## Other investigations on N45297 (2) 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 CEN10LA420](https://openairdocs.org/ntsb/CEN10LA420), Jul 21, 2010: Air Tractor AT-401 (N45297), Toulin, IL, substantial damage. Probable cause: A partial loss of engine power as a result of a cracked cylinder and the reduced visibility due to the oil-covered windshield. - [NTSB FTW94LA256](https://openairdocs.org/ntsb/FTW94LA256), Aug 2, 1994: Air Tractor AT-401 (N45297), Mcgehee, AR, substantial damage. Probable cause: TOTAL LOSS OF ENGINE POWER AS THE ENGINE SEIZED DUE TO A BLOWER BEARING FAILURE. A FACTOR WAS THE LACK OF SUITABLE TERRAIN FOR THE FORCED LANDING. 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.