# NTSB WPR12LA433: Air Tractor AT-502, N4556S, Firebaugh, CA, September 22, 2012 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: September 21, 2012, 17:00 local (Sep 22, 2012, 00:00 UTC) - Place: Firebaugh, CA - Coordinates: 36.806388, -120.622222 - Nearby events: https://openairdocs.org/map.md?lat=36.8064&lon=-120.6222&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Miscellaneous/other](https://openairdocs.org/ntsb-events/900) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report June 11, 2014 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: FAA FSDO - NTSB case key (mKey): 85114 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR12LA433 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/85114/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=85114 - Page: https://openairdocs.org/ntsb/WPR12LA433 ## Probable cause The pilot’s decision to continue the takeoff after the engine stopped producing its full-rated torque while operating in high-density altitude conditions and his subsequent failure to maintain clearance from the power transmission wires. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Action: lack of action](https://openairdocs.org/ntsb-findings/02041030): Personnel issues › Action/decision · Pilot (probable cause) - [Performance/control parameters: altitude](https://openairdocs.org/ntsb-findings/01062012): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause) - [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Pilot (probable cause) - [Temp/humidity/pressure: high density altitude](https://openairdocs.org/ntsb-findings/03031020): Environmental issues › Conditions/weather/phenomena · Effect on operation (probable cause) ## Analysis The pilot ferried the airplane to a private ag-operating airstrip where it was fully fueled, and 400 gallons of defoliant were loaded in the hopper. During the takeoff roll for the aerial application flight, the pilot noticed that the engine was not producing its full-rated torque, but he chose not to abort the takeoff. The pilot reported that, when the airplane reached the end of the runway, it lifted off but would not climb out of ground effect. As the airplane approached power transmission wires about 0.5 mile from the airstrip, the pilot began dumping the defoliant load to gain altitude. Dumping the load resulted in the airplane gaining some altitude, but, simultaneously, the airplane's nose pitched up, which increased drag and stopped the climb. The airplane struck the wires and landed hard in an open field. Postaccident examination of the engine found no preimpact mechanical anomalies that would have precluded normal engine operation. It is likely that the engine was not producing its full-rated torque because the density altitude was 2,400 feet (as compared to the field elevation of 236 feet), which reduced the available engine torque. ## Factual narrative On September 21, 2012, about 1700 Pacific daylight time, an Air Tractor, Inc., AT-502, N4556S, sustained substantial damage when it struck transmission wires and impacted terrain during takeoff initial climb near Firebaugh, California. The airline transport pilot was not injured. Thiel Air Care, Inc., was operating the airplane under the provisions of 14 Code of Federal Regulations Part 137. Visual meteorological conditions prevailed for the aerial application flight, which was originating at the time of the accident. A flight plan had not been filed. The pilot reported that he ferried the airplane about 25 nautical miles to the private ag-operating airstrip at an elevation of 236 feet. He went into the office to receive the details of his mission, while the airplane was being fully fueled and 400 gallons of defoliant loaded in the hopper. On takeoff roll, the pilot noticed that the engine was not producing its "fully rated torque." About halfway down the runway, because the airplane's tail was not coming up, he added more flaps to help raise it. The pilot said that, at the end of the runway, the airplane "struggled into ground effect and would not climb." As the airplane approached a power transmission line about 0.5 miles from the airstrip, the pilot began dumping the defoliant load in order to climb over the wires. Dumping the load resulted in the airplane gaining some altitude but simultaneously the nose came up, and the airplane reached a "very high" pitch attitude. Subsequently, the airplane impacted the wires and landed hard in an open field several hundred feet beyond the transmission line. The impact bent both wings and damaged the landing gear and engine compartment. On October 25, 2012, a field representative for the engine manufacturer examined the engine and airplane. The examination revealed no evidence of any preimpact mechanical malfunctions or failures. The fuel control unit, fuel pump, fuel heater, and propeller governor were sent to the manufacturer's facility in Quebec, Canada, for further examination. On November 21, 2012, these components were examined and tested under the supervision of an investigator from the Transportation Safety Board of Canada. The testing found no indications of any pre-impact mechanical anomalies or dysfunctions to the components that would have precluded normal engine operation. At 1653, the reported weather conditions at Madera, California, elevation 255 feet, located about 28 nautical miles east of the accident site, were wind from 290 degrees at 7 knots; sky clear, visibility 10 miles; temperature 32 degrees Celsius; dew point 7 degrees Celsius; and altimeter 29.85 inches of mercury. The calculated density altitude was 2,400 feet. ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Miscellaneous/other](https://openairdocs.org/ntsb-events/900) (defining event) - [Initial climb: Controlled flight into terr/obj (CFIT)](https://openairdocs.org/ntsb-events/120) ## Aircraft - Registration: [N4556S](https://openairdocs.org/deregistered/N4556S-2018-01-04), registration cancelled 2018-01-04, S/N 502-0137, 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: 502-0137 - Year built: 1991 - Airframe hours: 10147 - Engines: P&W PT6A SER 750 horsepower turbo prop - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Thiel Air Care Inc - Registered owner: Thiel Air Care Inc - Airworthiness certificate: Special, Restricted (Special) - Last inspection: 100 hour, August 8, 2012 - Departed: Firebaugh, CA - Destination: Firebaugh, CA - Flight plan: Unknown - Airport: runway 09, 2,300 × 35 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 35; injuries: none; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review March 25, 2012; seat: front; restraint: 4-point; flight hours: 10,608 total, 819 in this make and model, 147 in the last 90 days, 31 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 290° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 90 °F, dew point 45 °F - Altimeter: 29.85 inHg - Observed at: MAE, 28 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 20120922021699A](https://openairdocs.org/incident/20120922021699A), Sep 22, 2012: Air Tractor Inc AT-502, Firebaugh, CA, Substantial damage. At aproximately 5:10 pm the pilot was departing a private agriculteral airstrip for the first spraying application for the day. The aircraft was full of fuel… ## Docket (4 files) The files NTSB released with the investigation on April 17, 2014, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=85114. 5.6 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 3.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40411280&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Pilot's Statement to FAA (item 2, .PDF, 46 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40411281&FileExtension=.PDF&FileName=Pilot%27s%20Statement%20to%20FAA-Master.PDF - FAA Map of Accident Site (item 3, .PDF, 956 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40411282&FileExtension=.PDF&FileName=FAA%20Map%20of%20Accident%20Site-Master.PDF - Pratt & Whitney Report (item 4, .PDF, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40411283&FileExtension=.PDF&FileName=Pratt%20%26%20Whitney%20Report-Master.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.