# NTSB LAX00LA156: Bell 407, N175PA, Grand Canyon, AZ, April 16, 2000 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: April 16, 2000, 12:08 local (19:08 UTC) - Place: Grand Canyon, AZ - Coordinates: 36.030258, -112.020355 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=36.0303&lon=-112.0204&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 6 uninjured - Status: Completed, report July 17, 2001 - Report: Approved by Office Director - ADs cited in the narratives: [AD 2000-02-12](https://openairdocs.org/ad/2000-02-12) (OpenAirDocs) - NTSB case key (mKey): 48969 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX00LA156 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/48969/pdf - Page: https://openairdocs.org/ntsb/LAX00LA156 ## Probable cause The failure and subsequent disintegration of the oil cooler fan forward hanger bearing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Miscellaneous/other, cruise - normal - accessory drive assy,drive bearing - failure (cause) - accessory drive assy,drive bearing - disintegrated (cause) - rotor drive system,oil cooler drive shaft - autorotation - intentional, pilot in command - autorotation - misjudged, pilot in command - In flight collision with terrain/water, landing - flare/touchdown ## Analysis About 5 minutes after takeoff, while in cruise flight, the pilot felt a few short 'clunks' and then heard grinding noise and felt violent shaking. The pilot elected to perform a precautionary, autorotative, off-airport landing. During the landing flare, the tail rotor and tail stinger contacted the ground. The tail rotor blades were damaged, the stinger broken, and the tail rotor gearbox was fractured. The vibration that the pilot felt was traced to a failed bearing at the oil cooler fan forward hanger. The bearing was sent to the helicopter manufacturer for examination; however, a fracture mode could not be identified due to damage to the fracture surfaces. An airworthiness directive applied to the bearing and was complied with 11 flight hours prior to the accident. ## Factual narrative On April 16, 2000, at 1208 hours mountain standard time, a Bell 407, N175PA, was substantially damaged during a precautionary, autorotative, off-airport landing near Grand Canyon, Arizona. The commercial certificated pilot and five passengers were not injured. The local area sightseeing flight was operated under 14 CFR Part 135 by Papillon Airways, Inc. A company VFR flight plan was filed. Visual meteorological conditions prevailed for the flight that departed from the Grand Canyon National Park airport at 1205. The pilot reported he felt a few short "clunks" while in cruise flight about 5 minutes after takeoff. Next there was "a very loud grinding noise and the aircraft began to SHAKE VIOLENTLY." The pilot decided to autorotate to a nearby clearing. During the landing flare, the tail rotor and tail stinger contacted the ground. The tail rotor blades were damaged, the stinger broken, and the tail rotor gearbox was fractured. The vibration that the pilot felt was traced to a failed bearing at the oil cooler fan forward hanger. The bearing was sent to Bell Helicopter/Textron for examination; however, the laboratory report states that a fracture mode could not be identified due to damage to the fracture surfaces. Airworthiness Directive 2000-02-12 applied to the bearing and was complied with 11 flight hours prior to the accident. ## Aircraft - Registration: [N175PA](https://openairdocs.org/aircraft/N175PA), registered now, S/N 53154, built 1997 (OpenAirDocs) - Reported make and model: Bell 407 - Registry model: [Bell 407](https://openairdocs.org/model/bell-407) (registry code 1182206) (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: 53154 - Airframe hours: 1848 - Engines: Allison 250-C47B 647 horsepower turbo shaft - Damage: Substantial damage - Flight: Part 135 - Operator: Papillon Airways Inc., doing business as Papillon Grand Cyn Helicopters - Registered owner: India I Inc - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, March 31, 2000, 33 hours before - Departed: GCN, AZ - Flight plan: Company VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 39; commercial; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 7,222 total, 363 in this make and model, 7,170 as pilot in command, 99 in the last 90 days, 60 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 230° at 15 knots, gusting 20 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 61 °F, dew point 18 °F - Altimeter: 30.00 inHg - Observed at: GCN, 5 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 20000416005779A](https://openairdocs.org/incident/20000416005779A), Apr 16, 2000: Bell 407, Grand Canyon, AZ, No damage. (-23) During cruise flight, the pilot felt a severe vibration eminating from the rear portion of the helicopter. The pilot immediately entered autorotation to… ## Other investigations on N175PA (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 FTW03FA118](https://openairdocs.org/ntsb/FTW03FA118), Mar 27, 2003: Bell 407 (N175PA), Broadus, TX, destroyed, 2 fatal. Probable cause: The partial loss of engine power due to erratic fuel flow metering to the engine resulting from the single point failure of the PLA potentiometer in the hydro-mechanical fuel control unit. A… 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.