# NTSB NYC98LA006: Hiller UH-12C, N49983, Bennington, VT, October 5, 1997 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: October 5, 1997, 12:30 local (16:30 UTC) - Place: Bennington, VT - Location: 42.8711° N, 73.1802° W: Placed by OpenAirDocs: center of Bennington, VT, within about 6 miles (OpenAirDocs) - Nearby events: https://openairdocs.org/map.md?lat=42.8711&lon=-73.1802&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report June 21, 2000 - Report: Approved by Office Director - NTSB case key (mKey): 39483 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC98LA006 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/39483/pdf - Page: https://openairdocs.org/ntsb/NYC98LA006 ## Probable cause The failure of the cyclic control due to an improper modification by the pilot/owner. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, hover - in ground effect - rotorcraft flight control,cyclic control - failure (cause) - maintenance,modification - improper, pilot in command (cause) - Loss of control - in flight, hover - in ground effect - In flight collision with terrain/water, hover - in ground effect ## Analysis The certificated flight instructor (CFI)/owner had been demonstrating how to hover a helicopter to a student pilot. When the student pilot attempted to hover the helicopter, it began to roll right. The CFI then took hold of his controls, and the top of his cyclic stick detached. The helicopter then rolled right and collided with the ground. Examination revealed that the cyclic stick had been replaced with a military style cyclic. The owner reported that the cyclic had been cut down by removing a section of the cyclic, and the cyclic detached at the repaired joint. A review of the maintenance records did not reveal who or when the modification was performed. ## Factual narrative On October 5, 1997, about 1230 eastern daylight time, a Hiller UH-12C, N49983, was substantially damaged when it rolled over while hovering at the William H. Morse State Airport (5B5), Bennington, Vermont. The certificated flight instructor and student pilot were not injured. Visual meteorological conditions prevailed for the local instructional flight that originated at 5B5, about 1210. No flight plan had been filed for the flight conducted under 14 CFR Part 91. In the NTSB Form 6120.1/2, the certificated flight instructor (CFI)/owner stated that they had been hovering over a grass area, when the loss of control occurred and the helicopter rolled right onto it's side. According to a Federal Aviation Administration (FAA) Inspector, the CFI had been demonstrating how to hover a helicopter to a student pilot. While the student pilot was attempting to hover the helicopter, it began to roll right. When the CFI took hold of his controls, the top of his cyclic stick detached. The helicopter then rolled right and collided with the ground. Examination of the helicopter by the FAA Inspector revealed the helicopter's cyclic stick had been replaced with a military style cyclic. According to the FAA Inspector, the owner reported that the cyclic had been cut down by removing a section of the cyclic. The top of the cyclic detached at the repaired joint. A review of the maintenance records did not reveal who or when the modification was performed. ## Aircraft - Registration: [N49983](https://openairdocs.org/aircraft/N49983), registered now, S/N 850 (OpenAirDocs) - Reported make and model: Hiller UH-12C - Registry model: [Hiller UH-12C](https://openairdocs.org/model/hiller-uh-12c) (registry code 4360116) (OpenAirDocs) - Category: Helicopter - Serial number: 850 - Airframe hours: 5100 - Engines: Franklin 6V335-5D 210 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Registered owner: David A. Dinicola - Airworthiness certificate: Standard, Utility - Last inspection: Annual, March 26, 1997, 12 hours before - Departed: 5B5 - Airport: 5B5, William H. Morse State ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 40; commercial; medical: class 2, valid medical--no waivers/lim.; seat: center; flight hours: 471 total, 363 in this make and model, 471 as pilot in command, 5 in the last 90 days, 2 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 300° at 10 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 72 °F, dew point 59 °F - Altimeter: 30.00 inHg - Observed at: ALB, 29 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 19971005047449A](https://openairdocs.org/incident/19971005047449A), Oct 5, 1997: Hiller UH12C, Bennington, VT, Substantial damage. (-16) Instructor was demonstrating hovering to student near runway at the airport (5B5). Student pilot at the controls began drifting aircraft to the right.… ## Other investigations on N49983 (1) 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 ANC86LA058](https://openairdocs.org/ntsb/ANC86LA058), May 18, 1986: Hiller 12-C (N49983), Palmer, AK, 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.