# NTSB CHI07LA193: Hughes 369D, N500NC, Comfrey, MN, July 5, 2007 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 5, 2007, 08:00 local (13:00 UTC) - Place: Comfrey, MN - Coordinates: 44.1472222222222, -94.7333333333333 - Nearby events: https://openairdocs.org/map.md?lat=44.1472&lon=-94.7333&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report March 31, 2008 - Report: Approved by Office Director - Parties: Federal Aviation Administration - NTSB case key (mKey): 66167 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI07LA193 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/66167/pdf - Page: https://openairdocs.org/ntsb/CHI07LA193 ## Probable cause The loss of engine power due to the loose pressure line during aerial application maneuvers which resulted in a hard forced landing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power, maneuvering - aerial application - fuel system,line fitting - loose (cause) - Forced landing, descent - emergency - Hard landing, emergency descent/landing - terrain condition - ground ## Analysis A helicopter sustained substantial damage on impact with terrain during a forced landing following a loss of engine power during an aerial application spray run. The pilot reported that he "was able to land square on the skids, but the helicopter still bounced. The landing gear spread hitting the tanks, and snapping the uprights above the tanks. At that point, forward leg stuck in the ground, making the helicopter pitch forward. The blade in front made contact with the ground. The rotor system came around cutting the boom faring and tail off." The pressure line which connects to the Pg boss on the fuel control was found to be finger tight during an examination of the wreckage. ## Factual narrative On July 5, 2007, about 0800 central daylight time, N500NC, registered as Hughes 369D helicopter, piloted by a commercial pilot, sustained substantial damage on impact with terrain during a forced landing following a loss of engine power during an aerial application spray run near Comfrey, Minnesota. The local aerial application flight was operating under 14 CFR Part 137. No flight plan was on file. Visual meteorological conditions prevailed at the time of the accident. The pilot, the sole occupant, reported no injuries. The origin and destination of the flight are unknown. The pilot's accident report, in part, stated: On the second pass of the second load, and in the middle of the field headed west, the engine began to spool down in RPM. I heard the engine sound of lost RPM, at that time my eyes were on the wires that the aircraft was approaching, N2 Rotor was at or about the bottom Red Line. My choices were to attempt to auto rotate across the wires, the road, and the people to the field beyond. At that split second I decided to attempt the grass area south of the field. Low N2 and air speed (about 75 mph), lowered collective attempted a 180 [degree] auto rotation, the engine and rotor seemed to speed up or surge. I attempted to do the auto as best as I could. Was able to land square on the skids, but the helicopter still bounced. The landing gear spread hitting the tanks, and snapping the uprights above the tanks. At that point, forward leg stuck in the ground, making the helicopter pitch forward. The blade in front made contact with the ground. The rotor system came around cutting the boom faring and tail off. Federal Aviation Administration Inspectors examined the wreckage. The pressure line which connected to the Pg boss on the fuel control was found finger tight. ## Aircraft - Registration: [N500NC](https://openairdocs.org/aircraft/N500NC), registered now, S/N 1260052D, built 1977 (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) - Registry engine: [Allison 250-C20 series](https://openairdocs.org/engine/allison-250-c20-series) (registry code 03020, turbo-prop) (OpenAirDocs) - Category: Helicopter - Serial number: 1260052D - Airframe hours: 3284.7 - Engines: Allison 250-C20B 420 horsepower turbo shaft - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Teryjon Aviation Inc. - Registered owner: Big Bird Leasing Inc. - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, March 1, 2007 - Departed: MN ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 59; injuries: none; commercial; airplane ratings: single-engine land; medical: class 2, with waivers/limitations; last flight review November 1, 2006; seat: left; flight hours: 4,000 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: 310° at 4 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 72 °F, dew point 63 °F - Altimeter: 30.05 inHg - Observed at: KMKT, 45 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 20070705019599A](https://openairdocs.org/incident/20070705019599A), Jul 5, 2007: Hughes 369D, Comfrey, MN, Substantial damage. (-23) Pilot reported losing power during spray run. N2 was observed below minimum red line. Minimal altitude was obtained, chose to turn away from power lines… ## Other investigations on N500NC (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 CHI80DEM44](https://openairdocs.org/ntsb/CHI80DEM44), Aug 29, 1980: Hughes 500D (N500NC), Manistee, MI, 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.