Comes After Three Incidents In Three Weeks
Prompted by three
emergency landings over the past three weeks, on Monday Alaska
Airlines announced it will inspect its 40-plane fleet of Boeing
737-400 aircraft for possible problems related to flap
deployment.
The Seattle Post-Intelligencer reports three incidents related
to improper flap deployment -- on January 11, 20, and 26 --
involving two 737-400 Combis prompted the inspections. In all three
cases, the flaps failed to fully deploy on landing... prompting one
diversion to an airport with a longer runway.
Airline spokesman Paul McElroy said Alaska won't ground the
planes. Inspection of the entire 737-400 fleet is expected to last
two weeks.
"This aircraft is certified to land with the flaps fully up --
it's not preferable, but it could," McElroy said. "And flight crews
are trained for that."
On January 20, Alaska Flight 64 was approaching the short,
exposed runway in Wrangell, AK when the pilot discovered the
Combi's flaps would not extend past 10 degrees, instead of full 40
degree deployment. As the aircraft needs a longer runway to land
with only partial flaps, the crew diverted to Ketchikan, where the
plane made a safe landing. The pilot declared an emergency, as is
called for in such cases.
That aircraft was flown to Anchorage for repairs, and was put
back into service 22 hours later. The same Combi had encountered
similar difficulties on January 11, and made an emergency landing
in Anchorage then, according to Alaska Airlines.
On Saturday, Flight 64 -- same route, but a different Combi --
declared an emergency on approach to land at Ketchikan.
"Once the second incident occurred, we decided to inspect all
the others, to see whether they have the same hardware-wear issue,"
McElroy said. The problem was traced to the housing for the
machinery that deploys the flaps.
McElroy stressed the repairs weren't "required by the
manufacturer or the FAA. We're doing it just to improve
reliability." None of the emergency landings resulted in any
injuries or property damage.
The airline did not disclose the incidents, until the P-I
contacted the airline Monday in follow-up to reader comments.
Alaska was not required to notify the FAA or NTSB, according to
McElroy, but personnel with both agencies, along with Boeing, have
since been contacted.
Five of Alaska's 40 -400s are Combis, which have been converted
to carry both cargo and passengers (an older, 737-200 Combi, is
shown above.) It is not known whether the problem may be unique to
the Combi fleet.