# NTSB CHI05LA045: Pilatus PC-12/45, N922RG, South Bend, IN, December 14, 2004 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: December 14, 2004, 13:30 local (18:30 UTC) - Place: South Bend, IN - Coordinates: 41.70861, -86.250556 - Nearby events: https://openairdocs.org/map.md?lat=41.7086&lon=-86.2506&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 5 uninjured - Status: Completed, report January 31, 2007 - Report: Approved by Office Director - Parties: FAA-South Bend FSDO, Transportation Safety Board of Canada, Pratt & Whitney Canada, Pilatus Business Aircraft Ltd., Greenhill Aviation, Woodward Governor Company - NTSB case key (mKey): 60730 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI05LA045 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/60730/pdf - Page: https://openairdocs.org/ntsb/CHI05LA045 ## Probable cause Failure of the fuel control unit (FCU) bellows which resulted in a significant loss of engine power and the pilot's encounter with unsuitable terrain during the subsequent forced landing. A contributing factor was the pilot's inadvertent exceedence of the engine temperature limitations during use of the manual override (MOR) system. Additional factors were the roadway and the utility poles struck during the forced landing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power, climb - fuel system,fuel control - failure (cause) - emergency procedure - attempted, pilot in command (contributing factor) - turbine assembly - overtemperature (contributing factor) - Forced landing, emergency descent/landing - On ground/water collision with object, emergency landing - unsuitable terrain or takeoff/landing/taxi area - encountered, pilot in command (cause) - terrain condition - roadway/highway (contributing factor) - object - utility pole (contributing factor) ## Analysis The airplane was substantially damaged during a forced landing following a loss of engine power. The pilot stated that shortly after takeoff, the engine "abruptly and smoothly rolled back." Movement of the power control lever had no effect. He stated that use of the manual override (MOR) system did not restore engine power. He secured the engine and executed a forced landing on a roadway. The airplane's wing struck two utility poles during rollout. Data downloaded from the accident aircraft indicated that the recorded engine interstage turbine temperature (ITT) exceeded published limits during the event. The post accident engine inspection revealed turbine damage consistent with an over-temperature event. The inspection also revealed a leak in the compressor discharge pressure (CDP) sensor bellows within the fuel control unit (FCU). The leak prevented the bellows assembly from responding to throttle inputs and resulted in the FCU providing minimum fuel flow to the engine regardless of the throttle setting. Following this accident an improved FCU design which incorporated a more robust bellows design was released and retrofited into the entire in-service and production fleet. The airframe manufacturer issued a revision to the pilot's operating handbook to provide an improved procedure for use in the event of an in-flight engine power loss. It also updated information regarding the Manual Override (MOR) system. ## Factual narrative HISTORY OF FLIGHT On December 14, 2004, about 1330 eastern standard time, a Pilatus PC-12/45, N922RG, operated by Greenhill Aviation Co. and piloted by an airline transport pilot, was substantially damaged during a forced landing following a loss of engine power near South Bend, Indiana. The corporate flight was being operated under 14 CFR Part 91 on an instrument flight rules (IFR) flight plan. The flight was reportedly in instrument meteorological conditions (IMC) at the time of the loss of engine power, however, visual meteorological conditions (VMC) prevailed at the accident site. The pilot and four passengers reported no injuries. The flight departed South Bend Regional Airport (SBN), South Bend, Indiana about 1315. The flight's intended destination was Westchester County Airport (HPN), White Plains, New York. The pilot stated that approximately 10 minutes after departing SBN, while climbing through 6,000 feet mean sea level (msl), the engine "abruptly and smoothly rolled back." He noted that smoke and flames were subsequently seen from both exhaust stacks. He reported that movement of the power control lever had no effect. He stated that use of the emergency manual override (MOR) system did not restore engine power. He then secured the engine. The pilot noted that he declared an emergency with South Bend approach control and requested radar vectors to the nearest airport. The air traffic controller informed him that SBN was the nearest airport and provided a heading. He reported that he configured the airplane at best glide airspeed and remained in IMC until descending through 3,000 feet msl. Upon exiting the clouds, the pilot obtained visual contact with the airport, however, the aircraft's altitude was not sufficient to reach it. According to the pilot, the flight was over the city of South Bend at that time and he ultimately elected to set-up for a landing on a roadway. He noted that traffic cleared at the last minute and he executed a landing on the road. During the rollout the right wing struck two utility poles before the airplane came to a stop. PERSONNEL INFORMATION The pilot-in-command held an airline transport pilot certificate with single-engine land and sea airplane, and multi-engine land and sea airplane ratings. He was issued a first-class medical certificate with no limitations in March 2004. The pilot reported a total flight time of 2,879 hours, with 30 hours in a Pilatus PC-12/45. He noted 50 flight hours during the past 30 days, with 30 hours in the PC-12/45. AIRCRAFT INFORMATION The accident airplane was a 2001 Pilatus PC-12/45, serial number 409. The aircraft was a single-engine, pressurized airplane, configured with six passenger seats and two flight crew (pilot) seats. The PC-12/45 was certified to operate at a maximum altitude of 30,000 feet, and had a maximum cruise speed of 270 knots. A Pratt & Whitney PT6A-67B turbo-shaft engine, serial number PCE-PR0271, capable of producing 1,200 horsepower, powered the accident airplane. According to the operator, the engine and airframe had accumulated 599 hours total time. The most recent inspection was completed on July 8, 2004, at 514 hours. METEOROLOGICAL INFORMATION The South Bend Regional Airport (SBN) Automated Surface Observing System (ASOS), at 1254, recorded: calm winds; 9 statute miles visibility; 2,400 feet above ground level (agl) scattered, 3,000 feet agl overcast; temperature and dew point -4 and -7 degrees Celsius, respectively; altimeter setting was 30.48 inches of mercury. At 1354, the SBN ASOS recorded: calm winds; 7 statute miles visibility in light snow; 3,400 feet agl overcast; temperature and dew point -4 and -7 degrees Celsius, respectively; altimeter setting was 30.47 inches of mercury. WRECKAGE AND IMPACT INFORMATION The airplane landed on U.S. Route 933, approximately 3 miles east of SBN. The aircraft came to a stop on the roadway. A section of the right wing from the end of the flap outboard was completely separated and located at the side of the road. An additional area of impact damage was located on the leading edge of the right wing about mid-span. The wing skin was crushed aft exposing the spar and sub-structure. The width of the crushed area was approximately the same as the diameter of a static wire support pole along the side of the roadway. Two utility poles were damaged. One was knocked down and the other had impact marks consistent with the height and thickness of the wing. The outboard section of the right wing was lying against the intact pole. TESTS AND RESEARCH Engine operating parameters were recorded on-board the aircraft during normal operations. Recorded parameters included the interstage turbine temperature (ITT) and fuel flow (FF). Data from the accident flight was downloaded and reviewed. Prior to the rollback, the ITT was stabilized approximately 600 degrees Celsius and the fuel flow maintained about 550 pounds per hour (lbs/hr). Beginning at 1322:24 (HHMM:SS), the ITT and FF decreased from 589 degrees Celsius and 521 lbs/hr, respectively, to 420 degrees Celsius and 79 lbs/hr. The ITT and FF then began to increase, reaching 1,028 degrees Celsius and 432 lbs/hr respectively, about 1322:53. The ITT maintained approximately 900 degrees Celsius, until it peaked again 60 seconds later at 1,283 degrees Celsius. A plot of the data is included in the docket material associated with this accident file. The pilot's operating handbook (POH) documented limitations related to engine operation. The POH denoted maximum ITT limits as follows: During starting for no more than 5 seconds, 1,000 degrees Celsius; transient for no more than 20 seconds, 870 degrees Celsius; takeoff for no more than 5 minutes, 800 degrees Celsius; and maximum continuous, 760 degrees Celsius. The engine assembly was removed for examination. A teardown was conducted at Pratt & Whitney Canada facilities under supervision of the Transportation Safety Board of Canada. Teardown inspection of the engine revealed that the first and second stage power turbine blades were fractured. The first stage blades were fractured approximately mid-span. Approximately one-half of the second stage blades were separated from the blade disc. The compressor blades exhibited damage at the tips, with portions of the blades missing. Noted damage was consistent with exposure to elevated temperatures. Examination and testing of the fuel control unit (FCU) revealed a leak in the compressor discharge pressure (CDP) sensor assembly bellows. The leak was located in a pit on the outer ply of the bellows. Additional pitting was observed near the leak site and on adjacent convolutions. There was no evidence of intergranular attack into the bellows material. There was no mechanical damage to the bellows. The CDP sensor consisted of the double-walled, hydro-formed bellows assembly fabricated from beryllium copper. Changes in CDP caused the bellows to expand or contract, which subsequently controlled a fuel valve. A leak in the bellows prevented the assembly from properly responding to pressure variations and resulted in the FCU providing minimum fuel flow to the engine regardless of throttle setting. The resulting power output of the engine at minimum fuel flow was insufficient to maintain level flight. ADDITIONAL INFORMATION Pratt & Whitney Canada, the manufacturer of the engine, issued Service Information Letter PT6A-128 in September 2004, regarding a prior in-flight engine power roll back on a PC-12 aircraft. The cause of the loss of engine power was attributed to a "loss of Fuel Control Unit (FCU) authority caused by leakage of the FCU bellows." The service letter noted that the leak was due to a perforation of the bellows at an inclusion in the material. The letter noted four previous events with similar malfunctions. Two of the events occurred in-flight, however, in those instances power wa ## Aircraft - Registration: [N922RG](https://openairdocs.org/deregistered/N922RG-2006-11-16), registration cancelled 2006-11-16, S/N 409, built 2001 (OpenAirDocs) - Reported make and model: Pilatus PC-12/45 - Registry model: [Pilatus PC-12/45](https://openairdocs.org/model/pilatus-pc-12-45) (registry code 7090551) (OpenAirDocs) - Registry engine: [Pratt & Whitney Canada PT6A-67B](https://openairdocs.org/engine/pratt-whitney-canada-pt6a-67b) (registry code 52158, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: 409 - Airframe hours: 599 - Engines: Pratt & Whitney Canada PT6A-67B 1200 horsepower turbo prop - Damage: Substantial damage - Flight: Executive/Corporate, Part 91 - Operator: Greenhill Aviation Co., LLC - Registered owner: Riversville Aircraft Corp. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, July 1, 2004, 84 hours before - Departed: SBN, South Bend, IN - Destination: HPN, White Plains, NY - Flight plan: IFR - Airport: SBN, South Bend Regional ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 25; injuries: none; flight instructor, airline transport; airplane ratings: single-engine sea, multi-engine land, single-engine land, multi-engine sea; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review October 1, 2004; seat: left; flight hours: 2,879 total, 30 in this make and model, 2,385 as pilot in command, 115 in the last 90 days, 50 in the last 30 days, 4 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 9 statute miles - Lowest ceiling: 3,000 ft overcast - Temperature: 25 °F, dew point 19 °F - Altimeter: 30.47 inHg - Observed at: SBN, 3 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 20041214033619A](https://openairdocs.org/incident/20041214033619A), Dec 14, 2004: Pilats PC1245, South Bend, IN, Substantial damage. (-23) The single engine Pilatus PC-12, N922RG departed on a flight from sbn at 13:05 to white plains. While climbing through 6000 ft. under IFR, the aircraft… 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.