If Additives Are Required, Board Says Flight Manuals Should Say So

The NTSB has issued a series of recommendations to the FAA dealing with certification requirements for aircraft requiring fuel additives, including fuel system icing inhibitors. The board says those limitations should be highlighted by a warning in the limitations section of the airplane flight manual.

The recommendation stems from an accident On March 22, 2009, about 1432 mountain daylight time, in which a Pilatus PC-12/45, N128CM, was diverting to Bert Mooney Airport (BTM), Butte, Montana, when it crashed about 2,100 feet west of runway 33 at BTM. The pilot and the 13 airplane passengers were fatally injured, and the airplane was substantially damaged by impact forces and a postcrash 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 (CFR) Part 91. The flight departed Oroville Municipal Airport (OVE), Oroville, California, on an instrument flight rules flight plan with a destination of Gallatin Field, Bozeman, Montana (BZN). Visual meteorological conditions prevailed at the time of the accident.

The NTSB determined that the probable cause of this accident was the pilot’s failure to ensure that a fuel system icing inhibitor was added to the fuel before the flights on the day of the accident; his failure to take appropriate remedial actions after a low fuel pressure state (resulting from icing within the fuel system) and a lateral fuel imbalance developed, including diverting to a suitable airport before the fuel imbalance became extreme; and a loss of control while the pilot was maneuvering the left-wing-heavy airplane near the approach end of the runway.

Pilatus PC-12 File Photo

As a result of the accident, the board has further recommended that the FAA require all existing certificated aircraft (both newly manufactured and in-service aircraft) that require fuel additives, including fuel system icing inhibitors, to have those limitations highlighted by a warning in the limitations section of the airplane flight manual, and amend aircraft certification fuel placarding requirements so that aircraft requiring fuel additives, including fuel system icing inhibitors, have a fuel filler placard that notes this limitation and refers to the airplane flight manual for specific information about the limitation.
 
Finally, the board recommends that the FAA require all existing certificated aircraft (both newly manufactured and in-service aircraft) that require fuel additives, including fuel system icing inhibitors, to have a fuel filler placard that notes this limitation and refers to the airplane flight manual for specific information about the limitation, and issue guidance on fuel system icing prevention that includes pilot precautions and procedures to avoid fuel system icing problems aboard turbine engine-powered aircraft and describes the possible consequences of failing to use a fuel system icing inhibitor, if required by the airplane flight manual, especially during operations at high altitudes and in cold temperatures.

FMI: www.ntsb.gov/doclib/recletters/2011/A-11-070-074.pdf