NTSB Recommends Rigorous Maintenance Programs For Firefighting
Aircraft
The NTSB has issued
recommendation letters to the Department of Agriculture, the
Department of Interior and to the FAA regarding maintenance
programs for aircraft used in fire fighting operations.
The recommendations are part of a package that includes probable
causes for three air tanker accidents caused by in-flight wing
separations resulting from fatigue fractures. The three accidents
are a June 17, 2002 crash of a C-130 in Walker, California
(LAX02GA201); the July 18, 2002 crash of a PB4Y-2 in Estes Park,
Colorado (DEN02GA074); and a revised narrative and probable cause
for the August 13, 1994 crash of a C-130 in Pearblossom, California
(LAX94FA323). All three aircraft were involved in firefighting
operations at the time of the accident. Fatigue cracking was cited
as the probable cause for all three accidents, with inadequate
fatigue detection procedures cited as a factor in each.
"We hope the release of these reports will raise operator
awareness of the unique problems that affect these specialized
aircraft, and the importance of a thorough maintenance program to
detect safety issues and prevent accidents," said NTSB Chairman
Ellen Engleman-Conners.
The Board's investigation of these accidents determined that the
maintenance and inspection programs currently applicable to
firefighting aircraft do not adequately account for the increased
safety risks that the aircraft are exposed to as a result of the
advanced age and the severe stresses of the firefighting
environment.
Firefighting flights conducted on behalf of the US Government
are public operations and are not required to comply with many of
the federal aviation regulations (FARs). However, many of the
maintenance provisions in the FARs do not address the unique safety
risks of firefighting aircraft.
As a result the Board
recommends that the Department of Agriculture and the Department of
Interior develop maintenance and inspection programs for
firefighting aircraft that include consideration of the airplane's
original design, age, and operational stresses, as well as
engineering evaluations to predict and prevent fatigue cracking.
The Board also recommends that the Department of Agriculture and
Department of Interior hire personnel with aviation engineering and
maintenance expertise to oversee the new maintenance programs.
Along with recommendations for more rigorous maintenance
programs for firefighting aircraft, the Board recommends that the
FAA require that restricted-category aircraft used in firefighting
operations be maintained in accordance with such programs. The
Safety Board further recommends that the FAA assume responsibility
for collecting continuing airworthiness information about surplus
military aircraft from the organization that last provided
technical or engineering support for an aircraft.
In a separate letter sent to the Department of Agriculture and
the Department of Interior the Safety Board emphasized their
position regarding the installation of video recorders on public
use aircraft and encouraging the agencies to do so without
delay.
The initial investigation of the Pearblossom accident in 1994
resulted in a different probable cause. However a recent review of
the accident information, including the examination of wreckage
that was not recovered in the initial investigation, revealed
previously undiscovered evidence of fatigue fracturing in
right-side, center-wing fragments that supported revising the
probable cause.