# NTSB FTW98LA367: Aerospatiale SA315B, N49525, Naturita, CO, August 22, 1998 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: August 22, 1998, 16:30 local (22:30 UTC) - Place: Naturita, CO - Coordinates: 38.209655, -108.560111 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.2097&lon=-108.5601&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report October 13, 2000 - Report: Approved by Office Director - NTSB case key (mKey): 43764 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW98LA367 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/43764/pdf - Page: https://openairdocs.org/ntsb/FTW98LA367 ## Probable cause Partial loss of engine power resulting from heat induced deterioration of the gas generator turbine. Factors were a forced landing in hilly unsuitable terrain containing mature trees. ## 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 - turboshaft engine,gas generator turbine - burned (cause) - turboshaft engine,gas generator turbine - eroded (cause) - reason for occurrence undetermined (cause) - Forced landing, descent - emergency - In flight collision with object, emergency descent/landing - object - tree(s) (contributing factor) - In flight collision with terrain/water, emergency landing - terrain condition - mountainous/hilly (contributing factor) - terrain condition - none suitable (contributing factor) ## Analysis While approaching a hover during external load operations carrying a 1,200-pound compressor, the engine lost partial power and the pilot conducted an emergency landing without releasing the load due to proximity of ground personnel. The landing was hard, in trees, and the helicopter sustained substantial damage. The pilot received serious injuries. Examination of the engine provided evidence of overheat in the turbine area and both the stator and turbine blades were eroded with the turbine blades eroded about 1/3 of their length. The fuel control and fuel pump were tested and operated within normal parameters. No evidence was found to explain the cause of the overheat. ## Factual narrative On August 22, 1998, approximately 1630 mountain daylight time, an Aerospatiale SA315B helicopter, N49525, was substantially damaged when it impacted terrain following a loss of engine power while maneuvering approximately 12.5 miles south of Naturita, Colorado. The commercial pilot, the sole occupant onboard, received minor injuries. Geo-Seis Helicopters, Inc., under Title 14 CFR Part 133, was operating the aircraft. Visual meteorological conditions prevailed, and no flight plan was filed. According to the operator, witnesses, and the pilot, the flight was transporting a 1,250-pound compressor on a 50-foot line. As the pilot was conducting his approach to a hover and was passing through about 100 feet above ground level, ground personnel said they heard a screeching noise and saw a 5-foot orange-colored flame coming from the engine exhaust. The helicopter settled and impacted terrain in a level attitude, but with sufficient force to cause substantial damage to the landing skids, airframe, tail boom, rotor blades, and tail rotor. The pilot did not release the load prior to landing due to the proximity of ground personnel. According to the pilot, while conducting his approach with the external load, he heard a "whirling" sound from the engine and the engine started to lose power. He said "It did not appear to be a total failure, just a gradual loss of power." As the helicopter descended through about 25 feet above the ground, the pilot said he executed a flare and landed in a small hole in some trees. Ground crewmen came to the aircraft and used the on board hand held fire extinguisher to put out a fire in the exhaust stack. They also shut off the fuel valve, electric power, and assisted the pilot, who was later transported to Saint Mary's Hospital in Grand Junction, Colorado, where he was examined. The examination revealed he had compression fractures to his lumbar spine. According to the operator, the allowed maximum gross weight of the helicopter for the conditions present was 4,900 pounds and the actual gross weight was 4,350 pounds. The altitude at the accident site was 6,300 feet, the temperature was 90 degrees Fahrenheit, the helicopter had 35 gallons of fuel aboard, the pilot weighed 172 pounds and the load weighed 1,200 pounds. According to calculations, these weather conditions would provide a density altitude of 9,500 feet. Performance charts indicate the helicopter was capable of hovering out of ground effect at the above weights and conditions. A review of the pilot's certification and training records provided documentation that he received his last FAR Part 133 and 135 proficiency checks from a designated check airman on January 29, 1998, and a proficiency check from the FAA on January 26, 1997. Records also provided information that he received a proficiency check from the Department of Interior, Office of Aviation Services (OAS), on external load operations and other OAS missions, on January 8, 1998. An examination of the engine and engine records was conducted. The engine log, power trend graphs, and engine oil sample analysis documents provided no evidence of engine abnormalities. The inlet, compressor section, and burner section appeared normal. The turbine section provided evidence of heat discoloration and erosion damage to the stators and outer 1/3 portion of the turbine blades on the gas generator. Pieces of the turbine blades and stator vanes were found in the exhaust casing at the accident site. (See attached photographs.) The engine fuel control and fuel pump were removed and functionally tested on a certified test bench at the facilities of Roberts Aircraft. Both units operated within normal parameters. See attached test data log. ## Aircraft - Registration: [N49525](https://openairdocs.org/deregistered/N49525-2011-09-28), registration cancelled 2011-09-28, S/N 2492, built 1976 (OpenAirDocs) - Reported make and model: Aerospatiale SA315B - Registry model: [Aerospatiale SA315B](https://openairdocs.org/model/aerospatiale-sa315b) (registry code 8680615) (OpenAirDocs) - Registry engine: [Turbomeca ARTOUSTEIIIB](https://openairdocs.org/engine/turbomeca-artousteiiib) (registry code 60003, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 2492 - Airframe hours: 13026 - Engines: Turbomeca ARTOUSTE IIIB 870 horsepower turbo shaft - Damage: Substantial damage - Fire: On-Ground - Flight: Business, Part 133 - Operator: Geo-Seis - Registered owner: Trans Aero Limited - Airworthiness certificate: Standard, Normal - Last inspection: AAIP, July 13, 1998, 76 hours before - Departed: NONE, NUCLA, CO ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 50; commercial; airplane ratings: single-engine land; instrument ratings: helicopter; medical: class 2, valid medical--w/ waivers/lim; seat: right; flight hours: 13,797 total, 13,797 as pilot in command, 129 in the last 90 days, 48 in the last 30 days, 4 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: variable at 4 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 90 °F, dew point 46 °F - Altimeter: 30.00 inHg - Observed at: MTJ, 50 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 19980822021559A](https://openairdocs.org/incident/19980822021559A), Aug 22, 1998: Aerosp SA315B, Nucla, CO, Substantial damage. Helicopter was either lifting or settling down a power unit when the acft lost power at 200 feet AGL and landed hard on the skids. (-23)the aircraft lost power… ## Other investigations on N49525 (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 ATL02LA067](https://openairdocs.org/ntsb/ATL02LA067), Mar 28, 2002: Aerospatiale AS315B (N49525), Hortense, GA, substantial damage. Probable cause: Failure of the engine to main transmission drive shaft due to improper installation by company maintenance personnel. A factor were the trees. 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.