Cites Two Recent Blade Failures On CRJ200s
Transportation Safety Board issued recommendations Wednesday to the
Federal Aviation Administration to address a safety concern raised
by two engine failures on Bombardier Canadair Regional Jet CRJ-200
aircraft. The Board states a flaw during the manufacturing process
for fan blades led to the two engine failures, and the Board wants
procedures set up to remove these blades before another incident
occurs. A companion recommendation was sent to the Canadian
In both instances -- a July 27, 2006 engine failure on an Air
Nostrum CRJ shortly after takeoff from Barcelona, Spain, and a May
24, 2007 engine failure on an Atlantic Southeast airlines CRJ while
in cruise flight from Syracuse to Atlanta -- a fan blade on a
General Electric CF34-3B1 turbofan engine fractured, causing a loud
bang, severe vibration and in one case an engine fire. Both flight
crews declared emergencies and landed safely with no injuries.
Examination of the blades showed that they failed due to a
material defect introduced during the manufacturing process,
according to NTSB investigators. The fan blades were manufactured
by Teleflex Aerospace Manufacturing Group, located in Mexico.
Teleflex has manufactured more than 28,000 of these blades.
"We are issuing this recommendation because we consider the
safety risk associated with this condition to be unacceptably
high," NTSB Chairman Mark V. Rosenker said.
The ASA fan blade failed after 4,717 cycles and 5,845 hours,
which is very early in a blade's service life, the Board said.
The Board issued six recommendations to the FAA, including that
it require GE Aviation to define a reasonable maximum time frame
below 4,717 cycles since new for these Teleflex fan blades and
require that the blades be removed from service before that limit
is exceeded, to require GE to include additional testing in the
manufacturing process for those blades, and to require GE to make
modifications in its CF34-1/-3 engine design to ensure that high
engine vibrations (such as can happen when a fan blade fractures)
will not cause the engine to catch fire.
The Board also issued a recommendation to Transport Canada, that
country's equivalent to the Department of Transportation, to
require Bombardier to redesign the retention feature of the CRJ
100/-200 engine throttle gearbox to ensure that it can withstand
the loads generated by a fan blade separation or similar event.
FMI: Read The Recommendations Here And Here (.pdf)