# NTSB ANC93LA125: Hughes 369D, N3115Y, Cordova, AK, July 24, 1993 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 23, 1993, 20:45 local (Jul 24, 1993, 04:45 UTC) - Place: Cordova, AK - Coordinates: 60.789176, -145.609252 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=60.7892&lon=-145.6093&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report August 17, 1994 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - NTSB case key (mKey): 2386 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC93LA125 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/2386/pdf - Page: https://openairdocs.org/ntsb/ANC93LA125 ## Probable cause A LOSS OF ENGINE POWER FOR UNDETERMINED REASONS. A FACTOR WAS THE ROUGH/UNEVEN TERRAIN. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power, hover - reason for occurrence undetermined (cause) - Forced landing, descent - emergency - Hard landing, descent - emergency - terrain condition - rough/uneven (contributing factor) ## Analysis WHILE HOVERING WITH JUST THE TOES OF THE SKIDS AGAINST THE APPROXIMATE 45 DEGREE SIDE OF THE MOUNTAIN, A LOAD THUMP WAS HEARD AND FELT BY THE PILOT AND PASSENGER AND THE HELICOPTER SETTLED BACKWARDS WITH THE TAIL COMING TO REST ON THE GROUND. THE PILOT SAID HE EXPERIENCED A PARTIAL LOSS OF ENGINE POWER AND COULD NOT MAINTAIN THE HOVER. THE ENGINE LATER OPERATED NORMALLY ON A TEST STAND. THE CAUSE OF THE POWER LOSS WAS NOT DETERMINED. ## Factual narrative HISTORY OF FLIGHT On July 23, 1993, at 2045 Alaska daylight time, a skid equipped Hughes 369D helicopter, N3115Y, operated by Soloy Helicopters, Inc. of Wasilla, Alaska, experienced a hard forced landing following a partial loss of engine power while hovering over steep terrain approximately 28 miles east of Cordova, Alaska. The airline transport pilot, one passenger, and one person on the ground beside the helicopter were not injured. The helicopter sustained substantial damage. The unscheduled domestic passenger/cargo flight, operating under 14 CFR Part 135, departed its base camp located about 15 miles to the southwest at 2030. Visual meteorological conditions existed, and a company VFR flight plan was filed. During a telephone conversation shortly after the accident the pilot stated the following, in part: "I was hovering with only the toes of the helicopter skids on the approximate 45 degree slope. The wind was calm, and the elevation was 700 feet above sea level. I was planning to land to pickup 2 passengers and some equipment to take to another location. One passenger had got in and fastened his seat belt, and the second person was handing cargo to the him and preparing to get in. I heard and felt a loud thump and the helicopter slowly settled backward to the ground. I kept increasing collective but the engine had lost power to where I could not maintain the hover. When the helicopter settled backward on the mountainside, the tail rotor blades hit the ground, the lower vertical stabilizer went into the ground, and the tail rotor driveshaft sheared. The engine was still running at about 70 percent N1. I shut the engine down and we got out very carefully. This was a newly cut landing area, and I had not landed there previously." The passenger stated that he heard and felt a loud thump just before the helicopter settled backwards. However, the person on the ground, about 4 feet from the helicopter, said he did not hear any unusual noise. TESTS AND RESEARCH Shortly after the accident, the engine was removed from N3115Y and taken to the Soloy Helicopters maintenance facility in Wasilla, Alaska. On August 3, 1993, a thorough examination was made of the engine under the supervision of FAA Inspector Richard L. Mason, FSDO (Flight Standards District Office), Anchorage, Alaska. A pneumatic systems check was performed during which a loose "B" nut was found on the governor. It was not determined if this nut had been loosened during the engines removal from the helicopter. The engine was taken to its manufacturer, Allison Gas Power Turbines, 2355 South Tibbs, Indianapolis, IN 46241-3644, for further examination and tests. An Allison official, Mr. Jeff Edwards, stated that the engine the Flight Standards District Office in Indianapolis. On September 15, 1993, the engines fuel pump was tested and found to be operational at NAC, 7200 Lockheed, Oakland, CA 94621. (Work Order # RAOOOO 1540). On September 17, 1993, the engines governor and fuel control were tested, and no anomalies found, at Allied Signal, Inc., 117 East Providencia Avenue, Burbank, CA 91502. (Work Order #s 23007506 and 23056935) ADDITIONAL INFORMATION Approximately 30 minutes before the accident, N3115Y had refueled at the company's base camp. No problems were found with the fuel or refueling system. No fuel or system problems were reported by any of the several other flightcrews using fuel from the same source. Following the accident, Soloy Helicopters President Chris Soloy stated that the results were negative from the pilot's post accident toxicological tests. ## Aircraft - Registration: [N3115Y](https://openairdocs.org/deregistered/N3115Y-1997-04-29), registration cancelled 1997-04-29, S/N 500716D (OpenAirDocs) - Reported make and model: HUGHES 369D - Registry model: [Hughes Helicopters HUGHES 369D](https://openairdocs.org/model/hughes-helicopters-hughes-369d) (registry code 4470706) (OpenAirDocs) - Category: Helicopter - Serial number: 500716D - Airframe hours: 6445 - Engines: ALLISON 350-C20B 312 horsepower turbo shaft - Damage: Substantial damage - Flight: Part 135 - Operator: Soloy Helicopters, Inc. - Registered owner: Soloy Helicopters, Inc. - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, July 12, 1993, 43 hours before - Departed: NONE, LOCAL CAMPT, AK - Flight plan: Company VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 49; airline transport, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane, helicopter; medical: class 2, valid medical--no waivers/lim.; seat: left; toxicology performed; flight hours: 10,000 total, 150 in this make and model, 8,000 as pilot in command, 150 in the last 90 days, 60 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 30 statute miles - Lowest ceiling: none - Temperature: 57 °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 19930723025509A](https://openairdocs.org/incident/19930723025509A), Jul 23, 1993: Hughes 369D, Cordova, AK, Substantial damage. Lost power during pinnicle landing hover. Fell backwards. Sheared tail rotor drive shaft. Cause undetermined. 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.