FAA officials as expected have issued a final airworthiness directive (AD)
aimed at mitigating the number of Bombardier CRJ100/200 stuck flap incidents
that have been linked to cold weather operations.
regulator in October 2007 proposed amending an August AD on CRJ100/2000 flaps
to include requirements that operators of the type in the USA provide
simulator training covering reduced- or zero-flap landings for pilots, and
perform several additional maintenance actions.
actions called for a pressure test of the flexible drive shaft in the flap
mechanism to check for leaks within two years or 4,000 flight hours after the
AD was approved. They also called for operators to perform a low-temperature
torque test of the flap actuator within two years of the AD.
a final AD issued today and effective February 15, the FAA has retained the
requirements of its original AD, and incorporated actions in its August notice
of proposed rulemaking (NPRM).
has also revised the AD to clarify that
new or repaired actuators with 2,000 or fewer flight hours since the pinion
seals were replaced are excluded from certain actions, following a request from
Delta Air Lines regional subsidiary Comair.
agency notes that one of the factors found to be contributing to the flap
problem “is lack of training in operating an airplane when flap failure occurs
in-flight, such as in freezing conditions”.
to the unsafe condition, we determined that these training requirements, in
conjunction with the other requirements of this AD, are necessary to safely
operate the airplane; and you must comply with them if you are an operator,” it
recently told ATI that a newly
redesigned flap system is about to be tabled for certification. The company has
also engaged flap actuator manufacturer Eaton to work on additional
modifications of the system.
work with Eaton, which is scheduled to begin in February, will further enhance
the system’s reliability, and is being done “in the spirit of continuous
improvement”, says Bombardier.
FAA notes that once this new seal is developed, approved, and available, it
“might consider additional rulemaking”. However, operators may request an
alternative method of compliance if the request includes data that prove that
the new action would provide an acceptable level of safety.
then, maintenance actions outlined in the AD “are intended to mitigate the
potential of flap failures utilizing the solutions that are currently
available”, says the regulator.
FAA estimates that the AD will affect 684 CRJ100/200 regional jets, and that it
will take about 27 work-hours per aircraft to comply with the basic
requirements of the directive. Based on an average labor rate of $80 per work-hour, the agency
estimates the cost of the AD to the US
operators to be nearly $1.5 million or $2,160 per regional jet.