# NTSB SEA04LA073: Hiller UH-12E, N9785C, Haines, OR, April 26, 2004 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: April 26, 2004, 16:00 local (23:00 UTC) - Place: Haines, OR - Coordinates: 44.874168, -117.993888 - Nearby events: https://openairdocs.org/map.md?lat=44.8742&lon=-117.9939&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report December 28, 2004 - Report: Approved by Office Director - Parties: Rolls Royce Corporation, FAA FSDO, Hiller Aircraft Corporation - NTSB case key (mKey): 59123 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA04LA073 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/59123/pdf - Page: https://openairdocs.org/ntsb/SEA04LA073 ## Probable cause A momentary partial loss of power for undetermined reason(s) and the pilot's failure to maintain adequate RPM during his autorotation landing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(partial) - nonmechanical, approach - reason for occurrence undetermined (cause) - Forced landing, emergency descent/landing - autorotation - Hard landing, landing - flare/touchdown - rotor rpm - not maintained, pilot in command (cause) - terrain condition - ground ## Analysis The pilot was descending through about 100 feet above the ground at 60 knots airspeed on approach to landing when he heard a loud bang. He immediately transitioned into an autorotation but as he flared prior to touchdown he had insufficient rotor RPM and the helicopter landed hard with the main rotor blades severing the tailboom. The pilot reported that as the helicopter impacted the ground he noted the Rolls Royce (Allison) 250-C20B engine spooling up. He also stated that he did not hear any audible engine out alert during the entire sequence and that the helicopter was not equipped with an auto-relight system. A post-crash test run of the engine revealed no abnormalities. The height-velocity diagram for the helicopter indicated that a successful auto-rotation could be accomplished at an elevation of 100 feet for airspeeds of 41 knots and above. ## Factual narrative On April 26, 2004, approximately 1615 Pacific daylight time, a Hiller UH-12E, N9785C, registered to/operated by Sundance Helicopters, Inc. and being flown by a commercial pilot sustained substantial damage during a hard landing following a mechanical malfunction while on short approach to landing near Haines, Oregon. The pilot suffered minor injuries. Visual meteorological conditions existed and no flight plan had been filed. The flight, which was returning from an agricultural spray run, was operated under 14 CFR 137, and had departed Elgin, Oregon, approximately 40 nautical miles north a short time before the accident. The pilot reported to the Safety Board's investigator that he departed Elgin with about 20 gallons of fuel aboard and as he was descending through about 100 feet above ground at 60 knots airspeed (refer to Attachment HV-I and HV-II) and approaching his base of operations he heard a loud bang. He immediately transitioned into an autorotation but as he flared prior to touchdown he had insufficient rotor RPM and the helicopter landed hard with the main rotor blades severing the tailboom. The pilot reported that as the helicopter impacted the ground he noted the Rolls Royce (Allison) 250-C20B engine spooling up and suspected a transmission malfunction. He also stated that he did not hear any audible engine out alert during the entire sequence and that the helicopter was not equipped with an auto-relight system. An inspector assigned to the Federal Aviation Administrations (FAA) Boise Flight Standards District Office (FSDO) examined the helicopter following the accident and found no outward evidence of any mechanical malfunction. The engine was shipped to the facilities of Rolls Royce in Indianapolis, Indiana, where it was examined. It was noted that there was no "O" ring at the base of the anti-ice valve and there was no rubber seal within the valve. The valve was replaced with a functional unit and the engine was test run. Engine performance during the test run was normal. The engine was subsequently returned to the Operator. ## Aircraft - Registration: [N9785C](https://openairdocs.org/aircraft/N9785C), registered now, S/N 2269 (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: 2269 - Airframe hours: 9152 - Engines: Allison 250-C20 400 horsepower turbo shaft - Damage: Substantial damage - Flight: Aerial application, Part 137 - Registered owner: Stevenson, Philip R. - Airworthiness certificate: Special, Restricted (Special) - Last inspection: 100 hour, February 26, 2004, 43 hours before - Departed: Elgin, OR - Destination: Haines, OR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 50; injuries: minor; commercial; medical: class 2, valid medical--w/ waivers/lim; last flight review July 10, 2003; seat: center; flight hours: 5,000 total, 4,000 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 80° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 77 °F, dew point 39 °F - Altimeter: 30.26 inHg - Observed at: BKE, 9 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 20040426009029A](https://openairdocs.org/incident/20040426009029A), Apr 26, 2004: Hiller UH12E, Haines, OR, Substantial damage. (-23) While returning to his main base following an aerial application job, at approximately 100 feet or less AGL the pilot heard a loud bang in the helicopter… ## Other investigations on N9785C (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 SEA93LA181](https://openairdocs.org/ntsb/SEA93LA181), Aug 23, 1993: Hiller UH-12E (N9785C), Auburn, WA, substantial damage. Probable cause: FAILURE OF THE CONNECTING ROD BOLT. THE HIGH VEGETATION WAS A FACTOR. - [NTSB SEA76FYC45](https://openairdocs.org/ntsb/SEA76FYC45), May 14, 1976: Hiller Acft UH-12E (N9785C), Tillamook, OR, destroyed - [NTSB SEA66A0066](https://openairdocs.org/ntsb/SEA66A0066), Jun 13, 1966: Hiller UH-12E (N9785C), Huntington, OR, substantial damage - [NTSB UNK64X1354](https://openairdocs.org/ntsb/UNK64X1354), Apr 17, 1964: Hiller 12E (N9785C), Pomeroy, WA, 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.