# NTSB LAX06TA284: Bell 212, N873HL, Happy Camp, CA, September 4, 2006 - Type: NTSB accident investigation - Classification: Accident · No injuries · Final report - Date: September 4, 2006, 15:50 local (22:50 UTC) - Place: Happy Camp, CA - Coordinates: 41.790554, -123.388885 - Nearby events: https://openairdocs.org/map.md?lat=41.7906&lon=-123.3889&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report September 27, 2007 - Report: Approved by Office Director - Parties: Scottsdale Flight Standards District Office, Pratt & Whitney Canada, Rogers Helicopters Inc., Transporation Safety Board - Canada - NTSB case key (mKey): 64475 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX06TA284 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/64475/pdf - Page: https://openairdocs.org/ntsb/LAX06TA284 ## Probable cause Failure of compressor second stage stator vane for undetermined reasons while maneuvering. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Miscellaneous/other, maneuvering - reason for occurrence undetermined (cause) - Forced landing, emergency landing - fire extinguishing equipment - activated, pilot in command - terrain condition - ground ## Analysis An engine fire warning light illuminated in the cockpit and the pilot observed smoke coming from the helicopter. He pulled the fire extinguisher handle on the number 2 engine and made a rapid descent to the airport. The pilot dropped the long line and landed without further incident. A post-landing examination of the helicopter revealed that the external surfaces of the Number 2 engine were covered in soot. A hole, which appeared to originate inside the engine, was observed on the gas generator case at the 5 o'clock position (aft looking forward). Post accident disassembly and inspection was performed on the number 2 engine. During the teardown, investigators found foreign debris, consistent in appearance to a stator vane, lodged in a diffuser pipe. The diffuser pipe, which directs compressor discharge air to the combustion area, was located at approximately the 5 o'clock position (aft looking forward). Further inspection revealed a fractured stator vane in the compressor second stage stator assembly. Due to impact and heat damage to the stator vane fracture surface, the cause of cracking could not be determined. Pratt & Whitney Canada investigators, in the presence of Federal Aviation Administration inspectors, concluded the following. "The perforation of the gas generator case was most likely caused by a disturbance of compressed air flow from the diffuser pipes. The restriction in airflow caused by the lodged stator vane limited the flow of combustion liner cooling air, resulting in a localized increase in temperature and subsequent burning through the combustion liner and the gas generator case." The engine teardown and inspection revealed no other significant anomalies. ## Factual narrative On September 4, 2006, at 1550 Pacific daylight time, a Bell 212 twin-engine helicopter, N873HL, made an emergency landing at the Happy Camp Airport after the pilot received an engine fire warning in flight near Happy Camp, California. The helicopter sustained substantial heat damage. The Department of Agriculture (USDA), U.S. Forest Service (USFS) was utilizing the helicopter under contract as a public-use firefighting tool under the provisions of 14 CFR Part 133, external load operations. The helicopter was registered to Rogers Helicopters, Inc., Fresno, California. The commercial pilot, sole occupant and employed by Rogers Helicopters, Inc., was uninjured. Visual meteorological conditions prevailed and a USFS flight plan had been filed. The local flight departed at 1549. According to initial accounts provided by the USFS, the helicopter departed Happy Camp airport with an external cargo load on a long line. Shortly after takeoff (about 30 to 45 seconds), the pilot smelled something burning. As the smell worsened, the pilot elected to return to the airport. In the cockpit, an engine fire warning light illuminated and the pilot observed smoke coming from the helicopter. He pulled the fire extinguisher handle on the number 2 engine and made a rapid descent to the airport. The pilot dropped the long line and landed without further incident. He shut down the engines, shut off the fuel valves, and exited the aircraft. A post-landing examination of the helicopter revealed that the external surfaces of the Number 2 engine were covered in soot. A hole was observed on the gas generator case at the 5 o'clock position (aft looking forward). The hole appeared to be originating from the inside of the case towards the outside. The engine compartment and other accessories on the right side of the helicopter sustained damage. Post accident disassembly and inspection was performed on the number 2 engine. During the teardown, investigators found foreign debris, consistent in appearance to a stator vane, lodged in a diffuser pipe. The diffuser pipe, which directs compressor discharge air to the combustion area, was located at approximately the 5 o'clock position (aft looking forward). Further inspection revealed a fractured stator vane in the compressor second stage stator assembly. Due to impact and heat damage to the stator vane fracture surface, the cause of cracking could not be determined. Pratt & Whitney Canada investigators, in the presence of Federal Aviation Administration inspectors, concluded the following. The perforation of the gas generator case was most likely caused by a disturbance of compressed air flow from the diffuser pipes. The restriction in airflow caused by the lodged stator vane limited the flow of combustion liner cooling air, resulting in a localized increase in temperature and subsequent burning through combustion liner and the gas generator case. The engine inspection revealed no other significant anomalies. ## Aircraft - Registration: [N873HL](https://openairdocs.org/deregistered/N873HL-2024-01-15), registration cancelled 2024-01-15, S/N 30873, built 1978 (OpenAirDocs) - Reported make and model: Bell 212 - Registry model: [Bell 212](https://openairdocs.org/model/bell-212) (registry code 1181420) (OpenAirDocs) - Registry engine: [Pratt & Whitney PT6 series](https://openairdocs.org/engine/pratt-whitney-pt6-series) (registry code 52033, turbo-prop) (OpenAirDocs) - Category: Helicopter - Serial number: 30873 - Airframe hours: 10647 - Engines: Pratt & Whitney Canada PT6T-3 turbo shaft; Pratt & Whitney Canada PT6T-3 turbo shaft - Damage: Substantial damage - Fire: In-Flight - Flight: External load, Public use - Operator: Department of Agriculture, U.S. Forest Service - Registered owner: Rogers Helicopters Inc. - Airworthiness certificate: Standard, Normal - Departed: 36S, Happy Camp, CA - Flight plan: Company VFR - Airport: 36S, Happy Camp ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 57; injuries: none; commercial; airplane ratings: single-engine land; medical: class 2, with waivers/limitations; seat: left; flight hours: 15,000 total, 1,500 in this make and model ## Weather - Conditions: Visual (VMC), Day - Visibility: 12 statute miles - Lowest ceiling: none - Temperature: 95 °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). - [Incident 20060904027729I](https://openairdocs.org/incident/20060904027729I), Sep 4, 2006: Bell 212, Happy Camp, CA, Substantial damage. (-23) After takeoff with an external load the pilot smelled what he believed at the time to be something burning. As the smell worsened, he then received a #2… ## Other investigations on N873HL (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 WPR23LA338](https://openairdocs.org/ntsb/WPR23LA338), Sep 10, 2023: Bell 212 (N873HL), Balch Camp, CA, destroyed. Probable cause: The pilot’s inadequate performance planning for the operation that resulted in an excessive gross weight for the operating conditions, leading to a loss of altitude during maneuvering and contact… 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.