A Series Of Operational Mistakes Resulted In The Fatal Injury
Of 14 People
The NTSB determined Tuesday that the cause of the March 2009
deadly crash of a Pilatus airplane was a series of operational
errors made by the pilot. The pilot failed to ensure that a
fuel system icing inhibitor (FSII), commonly referenced by the
brand name "Prist", was added to the fuel prior to the accident
flight.
The pilot also failed to take appropriate remedial actions,
including diverting to a suitable airport, after the airplane
warning systems indicated a low fuel pressure state that ultimately
resulted in a significant lateral fuel imbalance. And, the pilot
lost control while maneuvering the left-wing-heavy airplane near
the approach end of the runway.
"The pilot's pattern of poor decision making set in motion a
series of events that culminated in the deadly crash," said NTSB
Chairman Deborah A. P. Hersman. "Humans will make mistakes,
but that is why following procedures, using checklists and always
ensuring that a safety margin exists are so essential - aviation is
not forgiving when it comes to errors."
On March 22, 2009, at about 1432 MDT, a Pilatus PC-12/45,
N128CM, crashed about 2,100 feet west of runway 33 at Bert Mooney
Airport (BTM) in Butte, Montana. The flight departed Oroville
Municipal Airport in Oroville, California, en route to Gallatin
Field in Bozeman, Montana but the pilot diverted to Butte for
unknown reasons. The pilot and the 13 passengers were fatally
injured and the aircraft was substantially damaged by impact forces
and a post-crash fire.
The airplane was owned by Eagle Cap Leasing of Enterprise,
Oregon, and was operating as a personal flight under the provisions
of 14 Code of Federal Regulations Part 91. Visual meteorological
conditions prevailed at the time of the accident.
File Photo
During the investigation, the NTSB determined that the pilot did
not add a fuel system icing inhibitor when the airplane was fueled
on the day of the accident. The Pilatus flight manual states
that a fuel system icing inhibitor must be used for all flight
operations in ambient temperatures below 0 degrees Celsius to
prevent ice formation in the fuel system.
The NTSB concluded that the airplane experienced icing in the
fuel system which resulted in a left-wing-heavy fuel imbalance. The
increasing fuel level in the left tank and the depletion of the
fuel from the right tank should have been apparent to the pilot
because that information was presented on the fuel quantity
indicator. This should have prompted the pilot to divert the
airplane to an airport earlier in the flight as specified by the
airplane manufacturer.
The NTSB issued recommendations to the Federal Aviation
Administration and the European Aviation Safety Agency, to require
fuel filler placards and guidance on fuel system icing
prevention.