# NTSB NYC93GA151: Enstrom F-28C, N51786, Gallipolis, OH, August 12, 1993 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Final report - Date: August 12, 1993, 12:30 local (16:30 UTC) - Place: Gallipolis, OH - Coordinates: 38.820285, -82.189117 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.8203&lon=-82.1891&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: Serious injuries - Injuries: 1 serious, 1 minor - Status: Completed, report September 13, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 38596 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC93GA151 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/38596/pdf - Page: https://openairdocs.org/ntsb/NYC93GA151 ## Probable cause The pilot's improper use of the collective and throttle which resulted in a low rotor rpm condition and a loss of control, and an inflight collision with the terrain. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - in flight, takeoff - initial climb - collective - improper use of, pilot in command (cause) - throttle/power control - improper use of, pilot in command (cause) - rotor rpm - not maintained, pilot in command (cause) - Forced landing, descent - emergency - Nose down, landing - flare/touchdown ## Analysis THE PILOT ATTEMPTED A PINNACLE TAKEOFF FROM A GRASSY KNOLL. DURING THE TAKEOFF, HE ENCOUNTERED A LOW ROTOR RPM CONDITION IN WHICH THE ENGINE RPM AND MAIN ROTOR RPM DECREASED TOGETHER. THE PILOT SAID HE LOWERED THE COLLECTIVE; HOWEVER, HE WAS UNABLE TO RECOVER THE MAIN ROTOR RPM IN TIME TO PREVENT A FORCED LANDING. HE MADE A RUN ON LANDING IN A GRASSY AREA AND THE MAIN ROTOR AND TAIL ROTOR BLADES STRUCK THE GROUND. THE PASSENGER EXITED THE HELICOPTER WHILE THE MAIN ROTOR WAS STILL TURNING AND HE WAS STRUCK IN THE HEAD BY A BLADE. ACCORDING TO THE FAA BASIC HELICOPTER HANDBOOK, A CONDITION OF LOW ROTOR CAN BE CORRECTED BY REDUCING THE COLLECTIVE WHICH WILL DECREASE THE DRAG ON THE ROTOR, AND THEREFORE, INCREASE THE RPM. ACCORDING TO THE HELICOPTER MANUFACTURER, ONCE THE RPM DROPS BELOW THE NORMAL OPERATING RANGE IT COULD TAKE SEVERAL SECONDS FOR THE RPM TO RECOVER TO THE NORMAL OPERATING RANGE. ## Factual narrative On Thursday, August 12, 1993, at 1230 eastern standard time, an Enstrom F28C, N51786, operated by the State of Ohio, lost power on takeoff, and made a hard landing. The helicopter received substantial damage and the passenger received serious injuries. Visual meteorological conditions prevailed and the pilot was flight following on a company flight plan. In the NTSB Accident report, the pilot stated: ...Perry made a takeoff [from a grassy knoll] upwind to a three foot hover...Forward cyclic was applied and after moving approximately ten feet toward Gallia Centerpoint road Perry noted a rapid loss of RPM. Perry lowered the collective but still experienced a rapid loss of RPM...Perry attempted to slow the helicopter and ground contact was made at approximately 10-15 mph...The nose pitched forward and one main rotor made a ground strike. The tail then came down and made contact with the ground. Salisbury was yelling "Get out", "Get out, its going to catch on fire." Perry was attempting to shut down the helicopter, turn off fuel etc. Perry yelled at Salisbury to remain in the helicopter numerous times...and...did not hear Perry. Salisbury exited ...and was struck on the head by a main rotor blade.... When interviewed, after the accident, Mr. Perry said the main rotor and engine RPM needles came down together and did not split. In a telephone interview, Mr. Taylor, an accident investigator for Enstrom Helicopters said that for the main rotor RPM and engine RPM to decrease together as reported by the pilot, is an indication of too much pitch (collective) being applied for the engine power (throttle) available. Mr. Taylor said that once the RPM drops below the normal operating range, it could take several seconds for the RPM to recover to the normal operating range. According to the FAA Publication, Basic Helicopter Handbook, AC61-13B, page 25, Collective Pitch-throttle coordination: Collective pitch is the primary control for manifold pressure; the throttle is the primary control for rpm.... Problem: RPM low, manifold pressure high Solution: Lowering the collective pitch will reduce the manifold pressure, decrease drag on the rotor, and therefore, increase the RPM. On page 103, General rules for pinnacle and ridgeline operations, item 5: Since pinnacles and ridgelines are generally higher than the immediate surrounding terrain, gaining airspeed on the takeoff is more important than gaining altitude. The airspeed gained will cause a more rapid departure from the area. In addition to covering unfavorable terrain rapidly, a higher airspeed affords a more favorable glide angle and thus contributes to the changes of reaching a safe area in the event of a forced landing. If no suitable area is available, a higher airspeed will permit a more effective flare prior to making an autorotative landing. According to the report from the Ohio State Police, "...the knoll [where the helicopter departed] is elevated several feet above [the] farm fence. There is an abrupt downward slope from the knoll to the fence and the hayfield continues on a downward slope until it reaches the fence line at CR60 [County Road 60]." According to FAA Operations Inspector, Mr. Kevin M. Kelly, of the Cincinnati Flight Standards District Office, the engine was run satisfactorly and no problems were noted. ## Aircraft - Registration: [N51786](https://openairdocs.org/deregistered/N51786-2022-01-08), registration cancelled 2022-01-08, S/N 450, built 1978 (OpenAirDocs) - Reported make and model: ENSTROM F-28C - Registry model: [Enstrom F-28C](https://openairdocs.org/model/enstrom-f-28c) (registry code 3300407) (OpenAirDocs) - Registry engine: [Lycoming HIO-360 series](https://openairdocs.org/engine/lycoming-hio-360-series) (registry code 41524, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 450 - Airframe hours: 1324 - Engines: LYCOMING HIO-360-E1AD 205 horsepower reciprocating - Damage: Substantial damage - Flight: Public aircraft, Part 91 - Operator: State Of Ohio, Bcii - Registered owner: New Horizons Helicopters - Airworthiness certificate: Standard, Normal - Last inspection: Annual, August 11, 1993, 7 hours before - Flight plan: Company VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 37; commercial; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 833 total, 161 in this make and model, 833 as pilot in command, 161 in the last 90 days, 47 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 330° at 7 knots - Visibility: 6 statute miles - Temperature: 86 °F ## 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 19930812029219A](https://openairdocs.org/incident/19930812029219A), Aug 12, 1993: Enstrm F28C, Gallipolis, OH, Substantial damage. Attempted pinnacle takeoff from knoll. Lost rotor and engine rpms. Run on landing. Rolled. Failed reduce collective ## Other investigations on N51786 (2) 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 BFO96LA003](https://openairdocs.org/ntsb/BFO96LA003), Oct 6, 1995: Enstrom F28-280C (N51786), Blue Ash, OH, substantial damage. Probable cause: the commercial pilot's failure to maintain clearance from obstacles during hover-taxi operations. Related factors the tailwind, the nearby obstacle, and the misjudged maneuver to avoid obstacles. - [NTSB CHI80FEK17](https://openairdocs.org/ntsb/CHI80FEK17), Jun 27, 1980: Enstrom F-28C (N51786), Columbus, OH, 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.