# NTSB FTW99LA140: Air Tractor AT-301, N4329S, Brownwood, TX, May 14, 1999 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: May 14, 1999, 12:09 local (17:09 UTC) - Place: Brownwood, TX - Location: 31.7129° N, 98.9771° W: Placed by OpenAirDocs: center of Brownwood, TX, within about 6 miles (OpenAirDocs) - Nearby events: https://openairdocs.org/map.md?lat=31.7129&lon=-98.9771&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report June 21, 2000 - Report: Approved by Office Director - NTSB case key (mKey): 46329 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW99LA140 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/46329/pdf - Page: https://openairdocs.org/ntsb/FTW99LA140 ## Probable cause The failure of the pilot-in-command to use the manufacturer's published checklist and extend the flaps prior to takeoff. A factor was the pilot's fatigued physiological condition as a result of extended flight and ground duty hours. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight collision with object, takeoff - initial climb - lowering of flaps - not performed, pilot in command (cause) - checklist - not used, pilot in command (cause) - fatigue(flight and ground schedule), pilot in command (contributing factor) - object - tree(s) ## Analysis The pilot stated that during the 3 weeks prior to the accident, he had averaged 15-hour work days. On the day of the accident, the pilot's first flight, which was a ferry flight to the airstrip, commenced at 0600. At 0722, he began the aerial application flights. At 1203, the airplane returned from the 20th application flight and was refueled. During the refueling, the pilot retracted the flaps to 'improve the footing' of the person who was fueling the left main fuel tank. The pilot stated that he did not extend the flaps prior to the 21st takeoff, and he did not use a checklist. The pilot stated that after takeoff the 'airplane wouldn't climb.' The airplane impacted trees during the initial climb after takeoff. The airplane flight manual requires that the flaps be extended 10 degrees prior to takeoff with a full hopper load or from a 'short' runway. The flap actuator jack screw and ball nut assembly were examined, and the ball nut was observed within 1/4 inch of the large gear-box ball bearing on the jack screw. This finding is consistent with the flaps being in the retracted position. ## Factual narrative On May 14, 1999, at 1209 central daylight time, an Air Tractor AT-301, agricultural airplane, N4329S, impacted trees during the takeoff/initial climb near Brownwood, Texas. The aircraft was owned by Ag-Air Equipment, Inc., of Wichita Falls, Texas, and operated by Flying V Air Service Inc., of Wichita Falls, Texas. The commercial pilot, sole occupant, received minor injuries. The airplane was destroyed by impact forces and a fire. Visual meteorological conditions prevailed for the 14 Code of Federal Regulations Part 137 aerial application flight, and a flight plan was not filed. The local flight was originating from a private grass airstrip at the time of the accident. According to the 2,000-hour pilot, during the 3 weeks prior to the accident, he had averaged 15-hour work days, which consisted of flight and ground duty. On the day of the accident, the pilot's first flight, which was a ferry flight to the private airstrip, commenced at 0600. At 0722, the airplane began spraying local fields with a mixture of water and zinc sulfate solution. At 1203, the airplane returned to the airstrip from its 20th application flight and was refueled. During the refueling process, the pilot retracted the flaps to "improve the footing" of the person, who was fueling the left main wing fuel tank. The 320-gallon hopper tank was then loaded with 300 gallons of spray solution in preparation for the airplane's 21st application flight of the day. The pilot initiated the takeoff roll to the southeast from the 3,000 foot, wet, soft, airstrip. The pilot reported in a written statement that he "failed to extend the flaps for takeoff." The pilot stated that it "felt like [the airplane] wouldn't climb." Subsequently, the airplane contacted a tree, which was located at the departure end of the airstrip, "dead center on the engine." The right wing contacted another tree and separated at midspan, and the left wing contacted a tree and separated 3 feet inboard from the wing-tip. The airplane contacted the ground and came to rest inverted approximately 150 feet beyond the departure end of the airstrip. A postcrash fire erupted and consumed the airplane. The pilot exited the airplane from the left door. The pilot reported that at the time of the accident, the visibility was greater than 10 miles, there were broken clouds at 10,000 feet, and the winds were from 180 degrees at 10 knots, gusting to 15 knots. At the request of the NTSB investigator-in-charge, a representative from Air Tractor, Inc., examined the airplane at the accident site. He identified the flap actuator jack screw and ball nut assembly in the wreckage. The ball nut was located within 1/4 inch of the large gear-box ball bearing on the jack screw. According to the representative, this finding is "consistent with the flaps being in the retracted position." The operations section of the AT-301 flight manual requires that the flaps be extended 10 degrees for takeoff when operating with a full hopper load or from a "short" airstrip. The pilot added that the Air Tractor owner's manual states that "10 degrees of flaps are required during takeoff to ensure clearing obstacles." The pilot stated that he did not use a checklist. The pilot stated in the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2) that this accident could have been prevented if the following actions had been taken: 1. Development and use of a checklist for Part 137 Operations. 2. Development and use of a company policy restricting "on-duty" and flight times for Part 137 operations. ## Aircraft - Registration: [N4329S](https://openairdocs.org/deregistered/N4329S-2000-08-05), registration cancelled 2000-08-05, S/N 301-0009 (OpenAirDocs) - Reported make and model: Air Tractor AT-301 - Registry model: [Air Tractor AT-301](https://openairdocs.org/model/air-tractor-at-301) (registry code 0390103) (OpenAirDocs) - Category: Airplane - Serial number: 301-0009 - Airframe hours: 5096 - Engines: P&W R-1340-AN-1 600 horsepower reciprocating - Damage: Destroyed - Fire: On-Ground - Flight: Aerial application, Part 137 - Operator: Flying V Air Service, Inc. - Registered owner: Ag-Air Equpiment Inc. - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, April 1, 1999, 100 hours before - Airport: NONE, Private Airstrip, runway 13, 3,000 × 30 ft, grass/turf ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 44; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: center; flight hours: 2,120 total, 1,063 in this make and model, 2,021 as pilot in command, 22 in the last 90 days, 13 in the last 30 days, 7 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 180° at 12 knots - Visibility: 15 statute miles - Lowest ceiling: none - Temperature: 86 °F, dew point 64 °F - Altimeter: 29.00 inHg - Observed at: MWL, 70 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 19990514022279A](https://openairdocs.org/incident/19990514022279A), May 14, 1999: Airtrc AT301, Brownwood, TX, Destroyed. (.19) On may 14, 1999, at 1300 central daylight time, an air tractor AT-301, agricultural airplane, N4329S, was destroyed by a post-crash fire after it… 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.