# NTSB DFW07LA167: Rotorway 162F, N888TD, Stratford, OK, July 20, 2007 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 20, 2007, 11:00 local (16:00 UTC) - Place: Stratford, OK - Coordinates: 34.79111, -96.956108 - Nearby events: https://openairdocs.org/map.md?lat=34.7911&lon=-96.9561&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report November 29, 2007 - Report: Approved by Office Director - Parties: FAA/FSDO - NTSB case key (mKey): 66277 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DFW07LA167 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/66277/pdf - Page: https://openairdocs.org/ntsb/DFW07LA167 ## Probable cause The loss of engine power due to a seized supercharger. A contributing factor was the lack of suitable terrain for the forced landing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power, cruise - exhaust system,external supercharger - seized (cause) - Forced landing, emergency descent/landing - Roll over, emergency landing - terrain condition - rough/uneven - terrain condition - none suitable (contributing factor) ## Analysis The 5,770-hour commercial pilot/owner/builder of the single-engine experimental helicopter was in cruise flight at an altitude of approximately 1,000 feet, at an estimated airspeed between 70 and 100 knots, when "the helicopter suddenly yawed to the right." The pilot immediately and simultaneously applied left torque pedal to stop the yaw, lowered the collective, and entered an autorotation into the wind, at an airspeed of 70 knots. The helicopter touched down in an "uneven" field, rolled over, and came to rest on its left side. The pilot added that there were no warnings prior to or during the loss of power. A review of photographs of the damaged helicopter revealed structural damage to the airframe. The pilot reported that he had a total of 10 gallons of fuel on board at the time he departed and there was a small fuel spill at the accident site. At the time of the accident, the helicopter had accrued a total of 60.6 hours. Examination of the engine by the pilot revealed that the supercharger had seized which accounted for the loss of engine power. ## Factual narrative On July 20, 2007, at 1100 central daylight time, a single-engine Lister Rotorway 162F experimental helicopter, N888TD, was substantially damaged during a forced landing to a field following a reported loss of engine power near Stratford, Oklahoma. The commercial pilot, sole occupant of the helicopter, was not injured. The helicopter was registered to and operated by the pilot. No flight plan was filed for the local flight that departed from the pilot's backyard near Stratford, Oklahoma, at 1045. Visual meteorological conditions prevailed for the personal flight conducted under 14 Code of Federal Regulations Part 91. According to the pilot, the helicopter was in cruise flight at an altitude of approximately 1,000-feet, at an estimated airspeed between 70 and 100 knots, when "the helicopter suddenly yawed to the right." The pilot added that he immediately and simultaneously applied left torque pedal to stop the yaw, lowered the collective, and entered an autorotation into the wind, at an airspeed of 70 knots. The pilot landed the helicopter in an "uneven" field, and the helicopter rolled, coming to rest on its left side. The pilot further stated that there were no warnings prior to or during the loss of engine power and there had been no recent mechanical problems with the helicopter. A review of photographs of the damaged helicopter revealed that the main rotors were twisted, the left landing gear skid was displaced inward, a tail rotor blade had separated, and the tail boom skin was wrinkled. The pilot reported that he had a total of 10 gallons of fuel on board at the time he departed and there was a small fuel spill at the accident site. Additionally, the pilot reported that he was the builder of the helicopter and the Federal Aviation Administration (FAA) had issued an airworthiness certificate in January/February 2007. At the time of the accident, the helicopter had accrued a total of 60.6 hours. Examination of the engine by the pilot revealed that the supercharger had seized, which resulted in the loss of power. The pilot reported having accumulated a total of 5,770-flight hours, of which 780-hours were in helicopters, with 60.6-hours in the same make and model. Weather at the Ada Municipal Airport (ADH), near Ada, Oklahoma, located about 16-miles east of the accident site, at 1110, was reported as calm wind, visibility 10 statue miles, scattered clouds at 2,300 feet, scattered clouds at 2,900 feet, temperature 84 degrees Fahrenheit, dewpoint 71 degrees Fahrenheit, and a barometric pressure setting of 30.06 inches of Mercury. The weather report included a remark of lightning south of the airport. ## Aircraft - Registration: [N888TD](https://openairdocs.org/deregistered/N888TD-2008-03-10), registration cancelled 2008-03-10, S/N 001, built 2007 (OpenAirDocs) - Reported make and model: Rotorway 162F - Registry model: [Lister Thomas 162F](https://openairdocs.org/model/lister-thomas-162f) (registry code 056217V) (OpenAirDocs) - Registry engine: [Rotorway RI-162F](https://openairdocs.org/engine/rotorway-ri-162f) (registry code 55007, 4 cycle) (OpenAirDocs) - Category: Helicopter, amateur-built - Serial number: 001 - Airframe hours: 60.6 - Engines: Rotorway RI 162F 150 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Thomas Lister - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, February 1, 2006 - Departed: NONE, Stratford, OK - Airport: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 62; injuries: none; commercial, private, flight instructor; airplane ratings: single-engine land, single-engine sea, multi-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review December 1, 2006; seat: left; flight hours: 5,770 total, 60 in this make and model, 5,015 as pilot in command, 16 in the last 90 days, 16 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 0° at 0 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 84 °F, dew point 72 °F - Altimeter: 30.05 inHg - Observed at: ADH, 16 nm away 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.