# NTSB FTW00TA116: Hughes OH-6A, N6187Y, El Paso, TX, April 13, 2000 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Final report - Date: April 13, 2000, 11:20 local (16:20 UTC) - Place: El Paso, TX - Coordinates: 31.989553, -106.589279 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=31.9896&lon=-106.5893&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report April 6, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 49035 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW00TA116 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/49035/pdf - Page: https://openairdocs.org/ntsb/FTW00TA116 ## Probable cause The failure of the pilot to maintain rotor rpm during an autorotation, which resulted in a hard landing. A factor was the partial loss of engine power resulting from the separation of the power control line due to fatigue, as a consequence of improper installation. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(partial) - mech failure/malf, maneuvering - maintenance,installation - improper, unknown (contributing factor) - fuel system,pc line - fatigue (contributing factor) - fuel system,pc line - separation (contributing factor) - Forced landing, descent - emergency - autorotation - initiated, pilot in command - Hard landing, landing - flare/touchdown - rotor rpm - not maintained, pilot in command (cause) ## Analysis The helicopter's engine experienced a partial loss of engine power while maneuvering at 60 feet agl and a forward airspeed of approximately 10 knots. In response to the loss of engine power, the pilot 'increased power, pulled up on the collective, in order to increase airspeed.' The engine immediately began to 'coast down.' The pilot added that due to the relatively low altitude, slow airspeed, and insufficient rotor rpm available for the autorotation, the helicopter landed hard. Examination of the engine revealed that a power control (PC) line, which ran between the fuel control unit and governor, had separated. Metallurgical examination revealed that the PC line failed due to fatigue. A bend in the line was observed at the location corresponding to the base of the ferrule at the failed end, indicating that excessive force may have been used during installation of the line. It is likely that fatigue initiated due to the additional stresses placed on the tube by this bend. ## Factual narrative On April 13, 2000, at 1120 central daylight time, a Hughes OH-6A helicopter, N6187Y, was substantially damaged during a hard landing following a loss of engine power near El Paso, Texas. The commercial pilot, sole occupant of the helicopter, sustained minor injuries. The helicopter was registered to and operated by the U.S. Border Patrol Air Operations, El Paso, Texas. Visual meteorological conditions prevailed for the 14 Code of Federal Regulations Part 91 public use flight, for which no flight plan was filed. The local flight originated from the El Paso International Airport, El Paso, Texas, at 0900. According to the pilot, the helicopter experienced a partial loss of engine power during a patrol mission while maneuvering at 60 feet agl and "moving forward at an airspeed just below effective translational lift, approximately 10 knots." In response to the loss of engine power, he "increased power, pulled up on the collective, in order to increase airspeed." The engine immediately began to "coast down." The pilot initiated an autorotation and made a turn to the left, with the intent to land on a gravel road. He stated that due to the relatively low altitude, slow airspeed, and insufficient rotor rpm available for the autorotation, the helicopter landed hard and came to rest upright. Postaccident examination of the airframe revealed that the tailboom separated from the helicopter. One main rotor blade separated from the main rotor hub and the skids were spread. Additionally, examination of the Allison C20B turboshaft engine revealed that a power control line (PC line), which ran between the fuel control unit and governor, had separated. The PC line was examined at the NTSB Materials Laboratory in Washington, D.C. The line separated at the base of the flange portion of the line. A slight bend was observed .375 inch from the base of the flange. A circumferential impression was observed at the inner radius of the bend. The location of the impression corresponded with the end of the ferrule when properly assembled. The fracture surface on the flange portion was examined utilizing a scanning electron microscope. Two areas were observed which exhibited features consistent with fatigue. ## Aircraft - Registration: [N6187Y](https://openairdocs.org/deregistered/N6187Y-2005-02-16), registration cancelled 2005-02-16, S/N 69-16038 (OpenAirDocs) - Reported make and model: Hughes OH-6A - Registry model: [Hughes OH-6A](https://openairdocs.org/model/hughes-oh-6a) (registry code 4470905) (OpenAirDocs) - Category: Helicopter - Serial number: 69-16038 - Airframe hours: 6322 - Engines: Allison 250-C20B 420 horsepower turbo shaft - Damage: Substantial damage - Flight: Public aircraft, Part 91 - Registered owner: U.S. Border Patrol - Last inspection: Annual, March 29, 2000, 12 hours before - Departed: ELP, TX ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 46; flight instructor, commercial; airplane ratings: single-engine land; instrument ratings: helicopter, airplane; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 6,750 total, 3,500 in this make and model, 5,440 as pilot in command, 135 in the last 90 days, 45 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 180° at 6 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 64 °F, dew point 37 °F - Altimeter: 30.00 inHg - Observed at: ELP, 30 nm away 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.