# NTSB WPR11LA278: Air Tractor AT-502, N1515P, Blackfoot, ID, June 21, 2011 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: June 21, 2011, 16:21 local (22:21 UTC) - Place: Blackfoot, ID - Coordinates: 43.209167, -112.349441 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=43.2092&lon=-112.3494&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report April 24, 2012 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Adminsitration, Pratt & Whitney Canada - NTSB case key (mKey): 80848 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR11LA278 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/80848/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=80848 - Page: https://openairdocs.org/ntsb/WPR11LA278 ## Probable cause A partial loss of engine power during takeoff for undetermined reasons. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Air Tractor AT-502, 4 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=0390303), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Air Tractor AT-502, 3 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=0390303), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Initial climb: Controlled flight into terr/obj (CFIT)](https://openairdocs.org/ntsb-events/120); cases with it: [Air Tractor AT-502, 2 cases](https://openairdocs.org/ntsb-events/120/sequence.md?model=0390303), [All aircraft, 1,074 cases](https://openairdocs.org/ntsb-events/120/sequence.md) ## Analysis The pilot reported that, during takeoff for a local aerial application flight, the airplane became airborne slightly beyond the normal rotation point. As the airplane approached the departure end of the runway, the engine did not develop enough power to maintain flight. The pilot stated that due to the amount of runway remaining, he was unable to abort the takeoff. He then lowered the nose in an effort to gain more airspeed but did not jettison the chemical load in the hopper. Subsequently, the airplane struck multiple trees beyond the departure end of the runway and came to rest upright. Company personnel reported that, per the pilot's request prior to the accident flight, the airplane was loaded with an amount of chemical that was similar to amounts that he had been using throughout the day. Postaccident examination of the engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. Signatures observed on the engine's internal components exhibited characteristics of the engine developing power at the time of impact, likely in a high power range. The airplane was found to be within weight and balance limitations at the time of the accident. The reason for the engine to not develop sufficient power for the airplane to maintain a positive rate of climb could not be determined. ## Factual narrative On June 21, 2011, about 1621 mountain daylight time, an Air Tractor AT-502, N1515P, sustained substantial damage when it impacted trees during takeoff from the McCarley Field Airport, Blackfoot, Idaho, following a reported partial loss of engine power. The airplane was registered to Wells Fargo Bank Northwest, Salt Lake City, Utah, and operated by Vector Disease Control International, Little Rock, Arkansas, under the provisions of Title 14 Code of Federal Regulations Part 137. The commercial pilot, sole occupant of the airplane, was not injured. Visual meteorological conditions prevailed and no flight plan was filed for the local aerial application flight that was originating at the time of the accident. The pilot reported to the National Transportation Safety Board investigator-in-charge (IIC) that he had been flying throughout the day conducting local aerial application flights uneventfully with about 320 to 375 gallons of chemicals loaded in the hopper. Prior to takeoff on the accident flight, he conducted his pre takeoff checklist by setting the propeller, power lever, flaps, and verifying all engine gauges and flight controls. The pilot stated that during the takeoff roll on runway 1, the airplane became airborne slightly beyond the normal rotation point and that as the airplane approached the departure end of the runway, the engine failed to develop enough power to maintain flight. The pilot stated that he focused on flying the airplane and did not look at the engine gauges and that due to the amount of runway remaining; he was unable to abort the takeoff. The pilot said that he lowered the nose in an effort to gain more airspeed and did not jettison the chemical load in the hopper. The pilot reported that at the time of the accident, the airplane weighed approximately 6,914 pounds, which included the 320-gallons of chemicals in the hopper and three-quarters of a tank of fuel in the left and right wing tanks. The maximum gross weight of the airplane was 8,000 pounds. Examination of the airplane by local law enforcement revealed that the outboard six feet of the right wing was separated and the outboard three feet of the left wing was separated. Fuel was accounted for in both wing fuel tanks at the accident site. The wreckage was recovered to a secure location for further examination. Examination of the recovered turbine engine by a representative from Pratt & Whitney Canada, under the supervision of a Federal Aviation Administration (FAA) inspector revealed that the engine displayed circumferential contact signatures to the compressor turbine, the power turbine guide vane ring, the power turbine shroud, the power turbine, and impact fractures of the power turbine blades due to their making contact with their adjacent components under impact loads and external housing deformation. There were no indications of any pre-impact distress or operational dysfunction to any of the engine components examined. The representative from Pratt & WhitneyCanada noted within his report that the engine displayed contact signatures to its internal components characteristic of the engine developing power at the time of impact, likely in a high power range. The company representative responsible for loading the chemical mixture onto the airplane reported that prior to the accident flight the airplane was loaded with 304 gallons of water, 12 gallons of Ethephon, 1.81 gallons of Shar-Sheild, and 1.81 gallons of Quadris. The company representative further stated that this was the pilot's usual load and all amounts loaded onto the airplane were verified by the pilot. Review of recorded weather data at the Pocatello Regional Airport, located about 20 miles southwest of the accident site revealed at 1553, wind was from 270 degrees at 9 knots. The pilot reported that at the time of the accident, wind was from 250 degrees between 0 and 3 miles per hour. Using reported weather conditions, airport elevation, the approximate density altitude was calculated to be about 6,650 feet. ## Aircraft - Registration: [N1515P](https://openairdocs.org/deregistered/N1515P-2017-10-24), registration cancelled 2017-10-24, S/N 502-0149, built 1991 (OpenAirDocs) - Reported make and model: AIR TRACTOR INC AT-502 - Registry model: [Air Tractor AT-502](https://openairdocs.org/model/air-tractor-at-502) (registry code 0390303) (OpenAirDocs) - Registry engine: [Pratt & Whitney PT6A series](https://openairdocs.org/engine/pratt-whitney-pt6a-series) (registry code 52032, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: 502-0149 - Airframe hours: 5518 - Engines: P&W PT6A-15AG 680 horsepower turbo prop - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Vector Disease Control International - Registered owner: Wells Fargo Bank Northwest - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, February 7, 2011, 95 hours before - Departed: U02, Blackfoot, ID - Destination: U02, Blackfoot, ID - Airport: U02, McCarley Field Airport, runway 01, 4,314 × 75 ft ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 66; injuries: none; commercial; airplane ratings: single-engine land; medical: class 2, with waivers/limitations; last flight review October 15, 2009; seat: center; flight hours: 18,979 total, 4,500 in this make and model, 18,979 as pilot in command, 150 in the last 90 days, 95 in the last 30 days, 8 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 270° at 9 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 79 °F, dew point 37 °F - Altimeter: 30.07 inHg - Observed at: PIH, 20 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 20110621011769A](https://openairdocs.org/incident/20110621011769A), Jun 21, 2011: Air Tractor Inc AT-502, Blackfoot, ID, Destroyed. Pilot stated that he experanced a loss of power on takeoff. Aircraft became airborn cleared a fence when the power decayed, aircraft clipped the tops of trees… ## Docket (3 files) The files NTSB released with the investigation on March 22, 2012, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=80848. 3.7 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 405 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40363652&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Chemical Loader Statement (item 2, .PDF, 17 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40363653&FileExtension=.PDF&FileName=Chemical%20Loader%20Statement-Redacted.PDF - Pratt & Whitney Canada Engine Examination Report (35 Embedded Photos) (item 3, .PDF, 35 photos, 3.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40363654&FileExtension=.PDF&FileName=Pratt%20%26%20Whitney%20Canada%20Engine%20Examination%20Report%20(35%20Embedded%20Photos)-Redacted.PDF 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.