# NTSB CHI94LA147: Air Tractor AT-402, N91966, Sikeston, MO, May 5, 1994 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 5, 1994, 10:15 local (15:15 UTC) - Place: Sikeston, MO - Coordinates: 36.880493, -89.579811 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=36.8805&lon=-89.5798&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report February 24, 1995 - Report: Approved by Office Director - NTSB case key (mKey): 9518 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI94LA147 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/9518/pdf - Page: https://openairdocs.org/ntsb/CHI94LA147 ## Probable cause a fatigue failure of a compressor blade which resulted in a catostrophic engine failure. ## 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, takeoff - initial climb - compressor assembly,blade - fatigue (cause) - compressor assembly,blade - failure,total (cause) - Loss of control - in flight, takeoff - initial climb - aircraft control - not possible, pilot in command - In flight collision with terrain/water, descent - uncontrolled - Hazardous materials leak/spill, other ## Analysis THE PILOT REPORTED THAT IMMEDIATELY AFTER TAKEOFF A TOTAL LOSS OF ENGINE POWER OCCURRED AND THE AIRPLANE PITCHED NOSE DOWN. THE AIRPLANE CONTACTED THE TERRAIN OFF THE LEFT SIDE OF THE RUNWAY. THE AIRPLANE WAS LOADED WITH 340 GALLONS OF A PROWL HERBICIDE/WATER MIXTURE WHICH SPILLED. INSPECTION REVEALED A FAILURE OF ONE COMPRESSOR BLADE WHICH OCCURRED DUE TO HIGH CYCLE FATIGUE. THIS BLADE FAILURE THEN RESULTED IN FURTHER COMPRESSOR AND TURBINE BLADE DAMAGE IN THE ENGINE. ## Factual narrative On May 5, 1994, at 1015 central daylight time, an Airtractor AT- 402, N91966, operated by Dennis E. McGarity, collided with the terrain following a loss of engine power on takeoff from the Sikeston Airport, Sikeston, Missouri. The accident occurred at the initiation of the CFR 14 Part 137 agricultural application flight. Visual meteorological conditions prevailed and no flight plan was filed. The airplane was substantially damaged and the pilot was not injured. The flight was to have originated at the time of the accident. The pilot reported that immediately after lifting off the runway, a total loss of engine power occurred. He stated the airplane "pitched violently nose down" and collided with the terrain off the left side of the runway. The airplane was loaded with 25 gallons of PROWL Herbicide mixed with 315 gallons of water when the accident occurred. A chemical spill did occur. Post accident inspection by Federal Aviation Administration Inspectors revealed there was internal engine damage. The engine, a Pratt & Whitney PT-6A, was removed and taken to Aviall, Inc., for inspection under the observation of FAA Inspectors. During the inspection, it was determined that an internal failure of the engine had occurred. Compressor and power turbine blades were then shipped to Aviall's Metallurgical Laboratory for further inspection. This inspection revealed, "One C.T. blade had fractured through the airfoil in high cycle fatigue. The nature of the origin could not be determined. The remainder of the C.T. blades had fractured in tensile overload." See attached inspection report. ## Aircraft - Registration: [N91966](https://openairdocs.org/deregistered/N91966-2002-02-05), registration cancelled 2002-02-05, S/N 402-0941, built 1994 (OpenAirDocs) - Reported make and model: Air Tractor AT-402 - Registry model: [Air Tractor AT-402](https://openairdocs.org/model/air-tractor-at-402) (registry code 0390205) (OpenAirDocs) - Registry engine: [Pratt & Whitney PT6A series](https://openairdocs.org/engine/pratt-whitney-pt6a-series) (registry code 52034, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 941 - Airframe hours: 59 - Engines: P&W PT-6-15 680 horsepower turbo prop - Damage: Substantial damage - Flight: Aerial application, Part 137 - Registered owner: C.R. Breeden Enterprises, Inc - Airworthiness certificate: Special, Restricted (Special) - Last inspection: 100 hour, February 3, 1994, 59 hours before - Departed: SIK - Airport: SIK, Sikeston Memorial, runway 2, 5,502 × 100 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 42; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--no waivers/lim.; seat: center; flight hours: 8,750 total ## Weather - Conditions: Visual (VMC), Day - Wind: 240° at 8 knots - Visibility: 6 statute miles - Lowest ceiling: none - Temperature: 64 °F, dew point 54 °F - Altimeter: 30.00 inHg - Observed at: CGI, 21 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 19940505010109A](https://openairdocs.org/incident/19940505010109A), May 5, 1994: Airtrc AT402, Sikeston, MO, Substantial damage. Engine failed on takeoff. Aircraft pitched down violently and struck terrain. Compressor blade failure. ## Other investigations on N91966 (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 CHI01LA183](https://openairdocs.org/ntsb/CHI01LA183), Jun 22, 2001: Air Tractor AT-402 (N91966), Catron, MO, substantial damage. Probable cause: the failure of the pilot to maintain clearance from the electrical wires. 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.