Home' Asian Aviation : AAV Feb 2012 Contents 6 AsianAviation | FEBRUARY 2012
The Australian Transport Safety Bureau (ATSB)
has blamed a combination of flight-control
software design and problems with an air-
data inertial reference unit (ADIRU) for an in-
flight upset involving a Qantas Airbus A330,
which injured 110 passengers and nine crew.
The incident occurred in October 2008 on
an aircraft en route from Singapore to Perth,
carrying 303 passengers and nine crew. Of
the injured, 51 were later treated in hospital.
The aircraft suddenly pitched down
about 154km west of Learmonth, Western
Australia, due to a combination of problems
involving two aircraft systems: the flight
control computers and one of the aircraft's
three ADIRUs, the agency says.
"Due to a limitation in software design,
the flight-control computers commanded the
aircraft to pitch down in response to a very
rare pattern of incorrect angle of attack data
from one of the ADIRUs," the ATSB says.
"The in-flight upset ... was a unique event
and extremely unlikely to happen again."
ATSB Chief Commissioner Martin
Dolan says Airbus took prompt action to
reduce the likelihood of another similar
"Very soon after the accident, the
manufacturer issued new pilot procedures
to manage the effects of any future cases
of a similar ADIRU failure," Dolan says.
"The aircraft manufacturer then redesigned
its software. Passengers, crew and
operators can be confident that the same
type of accident will not happen again."
An investigation into what triggered
the ADIRU failure concluded that it was
"very unlikely" to have been caused by
electromagnetic interference from a Naval
Communications station at Exmouth, or
from a personal electronic device such as a
laptop or mobile phone. A number of other
possible triggers were also discounted.
Dolan says the accident served to
underline the importance of seat belts.
"At least 60 of the passengers were
seated without their seat belts fastened,"
he says. "Although some of those wearing
a seat belt were also injured, most of
the injuries occurred when unrestrained
occupants were thrown into the aircraft's
ceiling. The rate and severity of injuries
was much greater for those who were not
wearing a seat belt.". -- Andrzej Jeziorski
Commercial Aircraft Corporation of
China (COMAC) says it is ready to
begin type-inspection authorisation
(TIA) of the ARJ21-700 regional jet.
The aircraft completed a number
of certification test flights last year,
preparing it for TIA, which will
probably be the final stepping stone
before the aircraft is handed over to
the Civil Aviation Administration of
China (CAAC) for type certification.
The first delivery of the jetliner to
launch customer Chengdu Airlines
was previously scheduled to take
place by the end of last year, but has
been delayed by as much as a year
because of repeated hold-ups to the
COMAC completed static tests on
the aircraft on 14 April 2011, with
crosswind tests finished on 24 May.
Flutter testing, which began on 4
April, was completed in mid-August.
However, the company failed to
complete icing test by the mid-2011
deadline and stalling-speed tests were
also held up.
The baseline -700 version of the
aircraft is designed to accommodate
70 to 95 passengers. A stretched,
-900 version is also planned, which
will seat 95-105.
The manufacturer has received 239
orders to date -- the vast majority
from Chinese airlines and lessors,
although a handful of export orders
have come from Myanmar Airways,
Lao Airlines, Indonesian mining
company Merukh Enterprises and US
lessor GE Capital Aviation Services,
which has ordered five.
-- Andrzej Jeziorski
ATSB blames ADIRU failure, software for Qantas incident
ARJ21 approaches certification
Many of the injured passengers were not wearing seat belts.
NEWS IN BRIEF
THE INTERNATIONAL Air Transport Association (IATA) says
global traffic results for November showed a softening in
passenger markets, while air cargo remained weak compared
with levels attained earlier in the year. Passenger traffic was
4.3 percent above November 2010 levels, but this is skewed
as November 2010 was a particularly weak month. "The
softening in passenger markets becomes apparent when
comparing to the previous month," IATA says. "This shows
a 0.5 percent decline on a seasonally-adjusted basis."
Freight markets were 3.1 percent below November 2010
levels, despite a 1.1 percent increase from October 2011
performance. "Weak global economic performance is being
reflected in air transport markets," says IATA Director General
and Chief Executive Tony Tyler. He points out that freight
markets have contracted about 4 percent from January 2011
levels. "Although passenger markets have had some growth
relative to the beginning of the year -- about 2 percent -- the
trend has been both soft and volatile. Continuing economic
uncertainty will likely mean market shortcomings deepening
as we enter 2012," Tyler says.
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