# NTSB DFW07CA129: Grumman G-164A, N4673, Sayre, OK, June 6, 2007 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: June 6, 2007, 12:00 local (17:00 UTC) - Place: Sayre, OK - Coordinates: 35.166667, -99.663055 - Nearby events: https://openairdocs.org/map.md?lat=35.1667&lon=-99.6631&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 July 25, 2007 - Report: Approved by Office Director - Parties: Oklahoma City, Oklahoma - NTSB case key (mKey): 65938 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DFW07CA129 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/65938/pdf - Page: https://openairdocs.org/ntsb/DFW07CA129 ## Probable cause The partial loss of engine power on takeoff-initial climb for an undetermined reason. A factor associated with the accident was the lack of suitable terrain for a forced landing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power, takeoff - initial climb - reason for occurrence undetermined (cause) - Forced landing, emergency landing after takeoff - In flight collision with object, emergency landing after takeoff - object - tree(s) - Nose over, landing - terrain condition - none suitable (contributing factor) ## Analysis The airline transport pilot departed in a single-engine, low-wing airplane for the purpose of aerial application. He reported that during takeoff, at approximately 100 feet above ground level (AGL), the engine lost partial power. He was unable to maintain altitude, and made a controlled descent into small trees off the end of the runway and then nosed over. An FAA inspector examined the airplane, and reported there was sufficient fuel on board for the flight and both water accumulators were empty. The airplane's last annual inspection was on March 21, 2007. At the time of inspection, the airplane had a total of 7,392 hours. The engine had 7,500 total hours, and 100 hours since it was last inspected. The cause for the partial loss of engine power was not determined. ## Factual narrative The radial engine lost power during a full-lenght takeoff from the 5,017-foot long concrete runway. The 9,957-hour airline transport pilot was scheduled to perform a local aerial application flight. The pilot reported that the tailwheel-equipped airplane became airborne about the midfield point of the runway. As the airplane neared the departure end of the runway, while at an altitude of 100 feet agl, "engine roughness began" and the airplane was unable to maintain altitude. The pilot held the best climb airspeed and elected to make a controlled descent into small trees located off the departure end of the runway. The airplane nosed over, and came to rest in the inverted position. There was no fire. An FAA inspector examined the airplane and reported there was sufficient fuel on board for the flight and both water accumulators were empty. The airplane's last annual inspection was performed on March 21, 2007. At the time of inspection, the airplane had accrued a total of 7,392 hours. The 450-horsepower radial engine had accumulated 7,500 total hours and 100 hours since it was last inspected. The pilot calculated that weight of the airplane during takeoff was 4,330 pounds, 169 pounds below takeoff gross weight. He also calculated that the density altitude at the time of the mishap was 4,400 feet. The reason for the partial loss of engine power could not be determined. ## Aircraft - Registration: [N4673](https://openairdocs.org/deregistered/N4673-2024-09-14), registration cancelled 2024-09-14, S/N 1080, built 1973 (OpenAirDocs) - Reported make and model: Grumman G-164A - Registry model: [Grumman G-164A](https://openairdocs.org/model/grumman-g-164a) (registry code 3952704) (OpenAirDocs) - Registry engine: [Pratt & Whitney R1340 series](https://openairdocs.org/engine/pratt-whitney-r1340-series) (registry code 52016, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 1080 - Airframe hours: 7392 - Engines: Pratt & Whitney R-985 reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Registered owner: Lynn A. Flaten - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, March 1, 2007 - Departed: 304, Sayre, OK - Destination: 304 - Airport: 3O4, Sayre Municipal Airport, runway 017, 5,017 × 130 ft, concrete ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 49; injuries: none; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; seat: single; flight hours: 9,957 total, 150 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 225° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 90 °F 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.