# NTSB ATL00TA080: Bell OH-58C, N9142S, Tampa, FL, August 8, 2000 - Type: NTSB accident investigation - Classification: Accident · No injuries · Final report - Date: August 8, 2000, 18:30 local (22:30 UTC) - Place: Tampa, FL - Coordinates: 28.000728, -82.380203 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=28.0007&lon=-82.3802&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report April 6, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 50022 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL00TA080 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/50022/pdf - Page: https://openairdocs.org/ntsb/ATL00TA080 ## Probable cause The pilot's improper use of flight controls that resulted in low rotor induced oscillation during a practice autorotation. ## Analysis While attempting a practice 180-degree autorotative turn, an unusual vibration was felt in the airframe followed by a decrease in main rotor and engine rpm. The helicopter collided with the runway in a level attitude, bounced once, and then settled back onto the runway. The examination of the airframe disclosed that the tailboom was deformed and cracked but remained attached to the helicopter. The examination disclosed that the tailboom damage was associated with inflight low rotor induced oscillation and the airframe examination failed to disclose typical hard landing damage. ## Factual narrative On August 8, 2000, about 1830 eastern daylight time, a Bell OH-58C helicopter, N9142S, registered to and operated by the Hillsborough County Sheriffs Office, was substantially damaged when it collided with the ground during an attempted autorotation landing at Vandenberg Airport in Tampa, Florida. The helicopter-rated certified flight instructor (CFI) and one helicopter-rated commercial pilot were not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local instructional public use flight being conducted under Title 14 CFR Part 91. The flight originated from Tampa, Florida, at 1800. According to the certified flight instructor, they were practicing 180-degree autorotation landings on runway 5 while performing a 90-day pilot competency ride as required by the Sheriff's Office. The maneuver was initiated from a left downwind for runway 5 from 600 feet above ground level (agl) at 60 knots of airspeed. The collective was lowered to the full down position and the throttle was rolled to the flight idle position and a left turn was initiated. Sixty knots of airspeed was maintained and at approximately one quarter of the way through the turn, the rotor speed began climbing out of the high side of the green arc. Collective pitch was adjusted to maintain rotor speed in the center of the green arch. At approximately 200 feet agl, full engine power restored and the rotor and turbine needles rejoined. After completing the 180-degree turn, an unusual vibration was felt and rotor and turbine RPM started to decay. The helicopter touched down on the runway in a level attitude, bounced once, then settled back onto the runway. The examination of the helicopter disclosed that the tailboom was deformed and cracked but remained attached to the helicopter. Examination of the helicopter revealed no mechanical faults or failures. According to Bell Helicopter, the damage to the helicopter tailboom is normally associated to low rotor induced oscillation of the tail boom while the aircraft was still in flight. Examination of the helicopter failed to show structural damage associated with a hard landing. An Operations Safety Notice, published by Bell Helicopter Textron on September 13, 1984, stated that tailboom and aft fuselage damage can occur during an autorotation landing if the main rotor RPM is allowed to decay below 70 percent. Applying collective pitch in excess of that required could result in excessive flapping of the main rotor during or after touch down. This can result in damage to the tailboom and/or aft fuselage. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - in flight, maneuvering - autorotation - initiated, pilot in command - flight controls - improper use of, pilot in command (cause) - In flight collision with terrain/water, landing - flare/touchdown ## Aircraft - Registration: [N9142S](https://openairdocs.org/deregistered/N9142S-2017-03-01), registration cancelled 2017-03-01, S/N 71-20670 (OpenAirDocs) - Reported make and model: Bell OH-58C - Registry model: [Bell OH-58C](https://openairdocs.org/model/bell-oh-58c) (registry code 1181580) (OpenAirDocs) - Category: Helicopter - Serial number: 71-20670 - Airframe hours: 5364 - Engines: Allison T-63-A720 420 horsepower turbo shaft - Damage: Substantial damage - Flight: Public aircraft, Part 91 - Registered owner: Hillsborough Cty Sheriffs Off. - Airworthiness certificate: Special, Special flight (Special) - Last inspection: 100 hour, June 26, 2000, 91 hours before - Departed: X16 - Airport: X16, Vandenberg, runway 5, 5,000 × 100 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 53; commercial, private; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: right; flight hours: 1,150 total, 392 in this make and model, 952 as pilot in command, 60 in the last 90 days, 20 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 80° at 6 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 91 °F, dew point 70 °F - Altimeter: 30.00 inHg - Observed at: TPA, 11 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 20000808015389A](https://openairdocs.org/incident/20000808015389A), Aug 8, 2000: Arofal OH58C, Tampa, FL, No damage. (-23) This flight was a hillsborough county sheriff's dept. "Public use" a/c flight. VMC daylight conditions prevailed and the wind was down the rwy at 5… 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.