Pilatus PC-12/45, N128CM. March 22, 2009

Accident Information:

Date of accident: March 22, 2009
Type of aircraft: Pilatus PC-12/45
Aircraft registration: N128CM
Owner of aircraft: Eagle Cap Leasing of Enterprise, Oregon

Passengers on board: 13
Flight crew: 1
Fatalities: 14
Survivors: 0

Flight Origin: Oroville Municipal Airport, Oroville, California
Destination: Gallatin Field, Bozeman, Montana
Location of accident: Bert Mooney Airport (BTM), Butte, Montana. (2,100 feet west of runway 33 at BTM)
Cause of accident: Human error.

Accident summary:

On March 22, 2009 at about 1432 Montana local time, a Pilatus PC-12/45, N128CM crashed 2,100 feet west of runway 33 at Bert Mooney Airport (BTM), Butte, Montana. The aircraft was damaged by the impact force and post-crash fire, and is not equipped with a cockpit voice recorder or a flight data recorder. The weather condition was prevailed on the day of accident. 14 people suffered fatally injured including 13 passengers and 1 pilot. The flight originally departed from Oroville Municipal Airport, Oroville, California, and scheduled a flight plan to Gallatin Field, Bozeman, Montana. It was operated as a personal flight under the provisions of 14 Code of Federal Regulations (CFR) Part 91.

The accident report from the National Transportation Safety Board determines the probable cause of crash was due to 1. Pilot failed to ensure a fuel system icing inhibitor was added to fuel on the day of the accident. 2. He did not take appropriate actions after a low fuel pressure state, resulting fuel imbalance and was not able to divert to suitable airport before situation went extreme. 3. Pilot lost control while manoeuvring the left-wing-heavy airplane near the approach end of the runway. According to the accident report “All jet fuels contain trace amounts of water, and a FSII lowers the freezing point of water to -40º C to prevent the water from turning into ice crystals, which can block a fuel line or filter. (NTSB/AAR-11/05 PB2011-910405)

Investigation Outline:

- Examine aircraft wreckages and crash site

- Examine the pilot’s health and qualification

- Examine the fuel system, including fuel system emergency procedures, fuel boost pump tests. (NTSB concluded even if the low fuel pressure procedure
had been conducted in this accident, it would not have changed the result as FS II was not added to fuel.)

- Interview with his ex-employers

- Examine weather condition and weather receipt to pilot
(Weather was not the factor of the accident)

- Examine navigation aids

Investigation Operations:

1. Examine the fuel system of Pilatus PC-12 AFM

- Fuel system testing

- Examine the regulation and guideline of fuel imbalance system

- Examine the emergency procedures of fuel system and its condition at the time of accident

- Examine the anti-icing advisory and proved the anti-icing additives have passed the tests.

2. Study of the occupant restraints

-Examine the regulation of multiple occupants sharing a single seat and a single restraints system.

-Occupants would not have any benefit from the improved protection of the crashworthiness requirements of Part 23 in Safety Recommendations.

-The NTSB determines that this case would have been survivable if the accident had been less severe.

3. Analyse the pilot’s employment history
-The pilot was the sole pilot for the accident aircraft of his employer company Eagle Cap Leasing.

-According to the flight log, most of the flights conducted for this company would have needed FS II for its fuel. Record shows FS II was not requested
February and March 2009, which is about four times that aircraft was refuelled.

Factors contributed to the crash:

Pilot’s decision making

- The pilot did not request FS II when refuelling the aircraft on the day before the accident. He was aware that two flights he operated would have been at high altitude and experienced cold outside temperature.

- The pilot filled the three flight plans with incorrect passenger numbers. There was not enough seat beats for each passenger on the plane.

- He took off with weight exceeded maximum aircraft weight limit for two of the three flight legs.

- He refuelled again after arriving VCB but again, he did not requested for FS II for his flight.

- He did not follow the PC-12 aircraft manual to divert the plane to the nearest by the time maximum allowable fuel imbalance was exceeded. He pilot diverted to BTM when maximum allowable fuel imbalance was exceeded about 30 minutes, while LLJ and DLN were the closest airport to the aircraft.


- NTSB studied the pilot’s duty and flying hours before the accident. His wife refused to be interviewed, therefore, information of sleep and other fatigue factors could not be obtained.

- NTSB suspected fatigue was the major factor that affected the pilot’s decision making.

Recommendations to FAA:

Seat restraint system
- Require every occupant to have a separate seats and separate restraints.
- Require occupants that are under 2 years of age to have a separate seat and restrained by an appropriate child restraint system during take-off,
landing and turbulence.

Cockpit voice recorder
- Suggest all existing turbine-powered, non-experimental, non-restricted-category aircraft to be installed with a crash-resistant flight recorder system.
This system should be capable of recording cockpit audio, providing information of cockpit and outside view environment.

Guidance of the use of FS II
- NTSB suggested the FAA to include the consequences of failing the use of FS II in their guidance. It would increase the awareness and prevent fuel
system icing problems in turbine-engine aircraft.
- All existing aircraft that require fuel additives, including fuel system icing inhibitors, should have a highlighted warning in the limitation section of the
aircraft manual. A fuel filler placard should be included to note this limitation, and refer specific regulation from aircraft manual.


National Transportation Safety Board. July 12, 2011. Aircraft Accident Report: Loss of Control While Maneuvering. Pilatus PC-12/45, N128CM.
Butte, Montana (NTSB/AAR-11/05. PB2011-910405)

Want to know more?

National Transportation Safety Board. July 12, 2011. Aircraft Accident Report: Loss of Control While Maneuvering. Pilatus PC-12/45, N128CM.
Butte, Montana (NTSB/AAR-11/05. PB2011-910405)

For more information and pictures of the accident, refer to the accident report from NTSB: NTSB/AAR-11/05. PB2011-910405

Contributors to this page

Erica Lam

Authors / Editors

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