# NTSB LAX96LA279: Hiller UH-12E, N124HA, Healdsburg, CA, July 20, 1996 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 19, 1996, 18:30 local (Jul 20, 1996, 01:30 UTC) - Place: Healdsburg, CA - Coordinates: 38.629318, -122.890426 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.6293&lon=-122.8904&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report August 25, 1997 - Report: Approved by Office Director - NTSB case key (mKey): 29514 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX96LA279 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/29514/pdf - Page: https://openairdocs.org/ntsb/LAX96LA279 ## Probable cause The failure of the pilot to confirm a loss of power before entering autorotation after reading an erroneous instrument indication on the helicopter's dual tachometer. Factors in the accident were the erratic instrument, and maintenance personnel who failed to properly repair the system after the discrepancy was previously reported. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, cruise - misc rotorcraft,dual tachometer - erratic (contributing factor) - maintenance,service of aircraft/equipment - inadequate, other maintenance personnel (contributing factor) - electrical system,electric wiring - loose part/bolt/nut/clamp/etc (contributing factor) - In flight collision with terrain/water, emergency landing - engine instrument - not understood, pilot in command (cause) - autorotation - selected, pilot in command (contributing factor) - terrain condition - mountainous/hilly - object - tree(s) ## Analysis The pilot entered autorotation over unsuitable steep terrain and struck trees after observing split needles on the rotor/engine tachometer. The helicopter had a previous rotor-tach generator failure. The failure was attributed to a loose connection, and was allegedly repaired by the previous owner. The connection was found to produce intermittent and inaccurate instrument readings when the wire bundle was moved or flexed. The potting material within the electrical connector was found in poor condition. ## Factual narrative On July 19, 1996, at 1830 hours Pacific daylight time, a Hiller UH-12E, N124HA, collided with trees after the pilot entered autorotation after reacting to an erroneous rotor/engine tachometer reading near Healdsburg, California. The helicopter was substantially damaged. The certificated private pilot and passenger were not injured. The helicopter was being operated as a personal flight by the pilot/owner when the accident occurred. The flight originated from a private ranch at 1825, and was destined for the Healdsburg Municipal Airport. Visual meteorological conditions prevailed at the time. The pilot said he was flying at 1,400 feet msl and 70 knots when the needles on the rotor/engine tachometer instrument split. The engine decelerated to idle. The pilot entered an autorotation over unsuitable steep terrain and struck trees during the emergency descent. According to the Federal Aviation Administration (FAA), the helicopter had a previous rotor-tach generator failure. The failure was attributed to a loose connection and was allegedly repaired by the previous owner. The rotor-tach generator electrical connection was examined by an airframe and powerplant mechanic. The connection produced intermittent and inaccurate instrument readings when the wire bundle was moved or flexed. The mechanic attributed the erroneous instrument reading to the poor condition of potting material within the electrical connector. There was no evidence of mechanical failure or malfunction found with the helicopter's powerplant after the accident. The pilot indicated on his accident report his total aeronautical experience consisted of 485 hours, of which 157 were accrued in helicopters. ## Aircraft - Registration: [N124HA](https://openairdocs.org/deregistered/N124HA-2021-09-04), registration cancelled 2021-09-04, S/N HA3024, built 1975 (OpenAirDocs) - Reported make and model: Hiller UH-12E - Registry model: [Hiller UH-12E](https://openairdocs.org/model/hiller-uh-12e) (registry code 4360122) (OpenAirDocs) - Registry engine: [Lycoming VO-540 series](https://openairdocs.org/engine/lycoming-vo-540-series) (registry code 41534, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: HA3024 - Airframe hours: 4700 - Engines: Lycoming O-540 C2A 305 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Oren J. White - Airworthiness certificate: Standard, Normal - Last inspection: Annual, February 1, 1996, 5 hours before - Departed: HEALDSBURG, CA - Destination: O31, HEALDSBURG, CA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 56; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; seat: center; flight hours: 485 total, 150 in this make and model, 374 as pilot in command, 3 in the last 90 days, 3 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 270° at 3 knots - Visibility: 20 statute miles - Lowest ceiling: none - Temperature: 81 °F - Altimeter: 29.00 inHg ## 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 19960719018839A](https://openairdocs.org/incident/19960719018839A), Jul 19, 1996: Hiller UH12E, Healdsburg, CA, Substantial damage. Helicopter lost power and crashed. (.19) on July 19, 1996, at 1830 hours pacific daylight time, a Hiller UH-12E, N124HA, collided with trees after the pilot… 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.