# NTSB FTW02LA044: Bell 47G, N5226, Ardmore, OK, December 1, 2001 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: December 1, 2001, 10:30 local (16:30 UTC) - Place: Ardmore, OK - Coordinates: 34.14611, -97.122497 - Nearby events: https://openairdocs.org/map.md?lat=34.1461&lon=-97.1225&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report January 16, 2003 - Report: Approved by Office Director - Parties: FAA FSDO - NTSB case key (mKey): 53850 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW02LA044 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/53850/pdf - Page: https://openairdocs.org/ntsb/FTW02LA044 ## Probable cause the flight instructor's selection of an unsuitable area for practicing a full touchdown autorotation, which resulted in a nose over. A contributing factor was the soft ground. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - On ground/water encounter with terrain/water, landing - roll - emergency procedure - simulated, pilot in command(cfi) - unsuitable terrain or takeoff/landing/taxi area - selected, pilot in command(cfi) (cause) - terrain condition - soft (contributing factor) - Nose over, landing - roll - misc rotorcraft,main rotor/tail boom contact ## Analysis The student pilot had completed three power recovery autorotations to the south, and the flight instructor was to demonstrate a "full touchdown autorotation" to end the training session. The flight instructor initiated the autorotation at 1,500 feet msl and 60 knots to the airport's mid-field median. After slowing to 40 knots, the instructor began a flare to reduce the airspeed to 15-20 knots. At 10 feet agl, he pulled collective to cushion the landing. The helicopter touched down on the soft grassy area and slid for approximately 10 feet before starting to nose over. "The tail of the helicopter pitched upward into the blades, severing it." The helicopter rotated left approximately 270 degrees before coming to rest upright. The flight instructor stated that "weather had saturated the ground and caused the sod to be soft on the usual landing area. It was not visible from the helicopter." ## Factual narrative On December 1, 2001, at 1030 central standard time, a Bell 47G helicopter, N5226, was substantially damaged during a practice autorotational landing at the Ardmore Downtown Executive Airport near Ardmore, Oklahoma. The helicopter was registered to a private individual and operated by Versatile Helicopters, Inc., dba Versatile Aviation of Ardmore, Oklahoma. The flight instructor and the private pilot rated student were not injured. Visual meteorological conditions prevailed, and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 instructional flight. The local flight originated from the Ardmore Downtown Executive Airport, approximately one hour prior to the accident. The student pilot had completed three power recovery autorotations to the south, and the flight instructor was to demonstrate "a full touchdown autorotation" to end the training session. The flight instructor initiated the autorotation at 1,500 feet msl and 60 knots to the mid-field median. After slowing to 40 knots, the instructor began a flare to reduce the airspeed to 15-20 knots. At 10 feet agl, he pulled collective to cushion the landing. The helicopter touched down on the soft grassy area and slid for approximately 10 feet before starting to nose over. "The tail of the helicopter pitched upward into the blades, severing it." The helicopter rotated left approximately 270 degrees before coming to rest upright. The flight instructor stated that "weather had saturated the ground and caused the sod to be soft on the usual landing area. It was not visible from the helicopter." ## Aircraft - Registration: [N5226](https://openairdocs.org/deregistered/N5226-2014-10-27), registration cancelled 2014-10-27, S/N 37, built 1950 (OpenAirDocs) - Reported make and model: Bell 47G - Registry model: [Bell 47D1](https://openairdocs.org/model/bell-47d1) (registry code 1180802) (OpenAirDocs) - Registry engine: [Franklin 6V4 series](https://openairdocs.org/engine/franklin-6v4-series) (registry code 27033, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 37 - Airframe hours: 15438 - Engines: Franklin 6A-355-B1 180 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Registered owner: Versatile Helicopters, Inc. - Airworthiness certificate: Standard, Normal - Departed: 1F0, Ardmore, OK - Airport: 1F0, Ardmore Downtown Executive ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 33; injuries: none; flight instructor, private, commercial; airplane ratings: single-engine land; medical: class 3, valid medical--no waivers/lim.; last flight review August 21, 2001; seat: right; flight hours: 450 total - Student pilot; age 24; injuries: none; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; last flight review September 26, 2000; seat: left ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 52 °F, dew point 43 °F - Altimeter: 30.20 inHg - Observed at: 1F0 ## 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 20011201034399A](https://openairdocs.org/incident/20011201034399A), Dec 1, 2001: Bell 47G, Ardmore, OK, Substantial damage. (.19) On December 1, 2001, at 1030 central standard time, a Bell 47D1 helicopter, N5226, was substantially damaged during a practice autorotational landing at… ## Other investigations on N5226 (4) 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. - [NTSB FTW96LA192](https://openairdocs.org/ntsb/FTW96LA192), Apr 26, 1996: Bell 47D1 (N5226), Ardmore, OK, substantial damage. Probable cause: the student's inadvertent dynamic rollover, and inadequate supervision by the flight instructor. - [NTSB FTW85LA074](https://openairdocs.org/ntsb/FTW85LA074), Dec 7, 1984: Bell 47D1 (N5226), Ardmore, OK, substantial damage - [NTSB FTW76FPA15](https://openairdocs.org/ntsb/FTW76FPA15), Dec 7, 1975: Bell 47D-1 (N5226), Irving, TX, substantial damage - [NTSB LAX75FUA04](https://openairdocs.org/ntsb/LAX75FUA04), Jul 28, 1974: Bell 47D-1 (N5226), Seal Beach, CA, substantial damage 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.