The US FAA is giving operators of Bombardier CRJ100/200
regional jets until early October to update flight manuals and operations and
training procedures to deal with potential flap failures.
Carriers will have until early January to carry out
associated preventative maintenance actions.
The airworthiness directive (AD), issued today, is an
interim measure aimed at stemming a large number of stuck flap incidents that
have been linked to cold weather operations with the Canadian-made
“The (CRJ) airplanes have had a history of flap failures at
various positions for several years,” says the FAA. “Flap failure may result in
a significant increase in required landing distances (if stuck in the stowed
position) and higher fuel consumption than planned during a diversion (if
In the most noteworthy case, an Air Canada Jazz CRJ200ER on
approach to Prince George, British Columbia on November 21 aborted its
landing due to weather. The flaps, set at 45° for landing, would not retract
despite the crew’s attempts to recycle the flap circuit breakers. The pilots
ultimately diverted to Fort St John,
British Columbia, where they
landed with 512lb (232kg) of fuel remaining due to the additional drag from the
lowered flaps. The CRJ burns approximately 3,000lb per hr at cruise.
Before that incident, air safety investigators in Canada, who had
been researching the CRJ flap problems for a decade, had convinced themselves
the problems were more of a nuisance than a safety concern.
Afterward, the TSB sent a letter to Transport Canada
“indicating our concerns” over the flap problems, Real Levasseur,
chief of operations for air investigation for the Transportation Safety Board
(TSB), tells ATI.
Levasseur says the rate of
occurrences had been increasing year over year, with two to three incidents per
day in the worldwide fleet last winter, although concerns for safety did not
arise until the Jazz incident.
An incident typically involves a “disagree” between two the
four individually controlled flap panels, a situation that causes the
aircraft’s safety logic to lock the flaps in their current position so as to
not cause roll control problems for the pilots due to asymmetry. Levasseur says unlocking the flaps can only occur after the
aircraft has landed.
Under the FAA’s directive, which
was derived from a Transport Canada AD, US operators of the aircraft must
modify the flight manual to discuss possible fuel exhaustion if the flaps fail
“at other than 0 degrees” in combination with a diversion to another airport.
Operational procedures must be modified to cover three failure scenarios – flap
extended diversion, flap failure after takeoff, flap zero landing - and
training must include the three failure scenarios plus landing with less than
full flaps settings.
Maintenance actions, to be performed within 120 days of the
September 5 effective date of the AD, include cleaning and lubricating the
flexible shafts that drive the flaps and performing a detailed inspection of
the actuator connector sealant bead for signs of damage or delamination,
among other tasks.
The FAA in the AD says the actions are necessary “to improve
overall Flaps System reliability and bring the failure rate to an acceptable
level, until permanent solutions are implemented.”
Calls to Bombardier were not immediately returned, though Levasseur says the airframer continues
to work with Transport Canada
and others on long term solutions.