Page 31 - AAA JANUARY - FEBRUARY 2016 Online Magazine

FEATURE FLIGHT SAFETY

Four master cautions were
activated following the failure
of the RTLU which triggered the
ECAM message of ‘AUTO FLT RUD
TRV LIM SYS’. The crew response
to pull the FAC circuit breakers
following the fourth master
caution was one of the contributing
factors to the loss of the aircraft

A320s, while the Pilot Monitoring was the in pulling of the circuit breakers (CB) on the “The electrical interruption to the FAC
Pilot in Command (PIC) who had 4,687 hours Flight Augmentation Computer (FAC), as caused the autopilot to disengage and the
on the type. During the course of the flight, was recorded by the Flight Data Recorder flight control logic to change from Normal
the flight crew had to respond to repeated (FDR), according to the report. Law to Alternate Law,” says the report. With
Electronic Centralised Aircraft Monitoring The decision by the crew to pull the the protections available under Normal
(ECAM) messages of AUTO FLT RUD TRV FAC CBs while in flight as a response to Law now no longer available to the flight
LIM SYS, says the report. The four master the fourth ECAM message of AUTO FLT crew and the autopilot disengaged, the
cautions activated following the failure of RUD TRV LIM SYS proved to be a fatal aircraft in a matter of seconds reached a
the Rudder Travel Limiter which triggered one. It resulted in the fifth (at 2316:27 UTC) commanded altitude of 38,500 feet (ISIS),
ECAM messages. The crew performed the and sixth (at 2316:44 UTC) master caution its highest, also attaining its largest roll
correct ECAM actions, after the first three activations. The following events led to the angle at 104° to the left. The jetliner now
master caution activations. However, the loss of the jetliner with all lives on board. in an ‘Airplane Upset’ condition went into a
response of the crew to the fourth master Following the ECAM messages of AUTO FLT stall and descended at an average rate of
caution (2315:36 UTC) differed and resulted FAC 1 FAULT and AUTO FLT FAC 1+2 FAULT, 12,000 feet per minute, before impacting
the ocean. The importance of appropriate
and correct crew response in an emergency
AIRPLANE UPSET Despite some variations depending on situation on a modern jetliner can be gauged
Over the past few years, several aircraft model, a loss of control occurs from the fact that following the fifth and
accidents and incidents have occurred when one or more of the following sixth master caution activations at 2316:27
in which flight crew had to deal with situations arise: UTC and 2316:44 UTC, respectively, the
an unusual aircraft attitude. Airline aircraft climbed to 38,500 feet at 2317:41
pilots seldom encounter very steep • Nose-up angle greater than 25° UTC, as a result of pilot inputs following the
bank or pitch angles associated with • Nose-down angle greater than 10° autopilot disengagement. Just over four
this type of loss of control. There are • Bank angle greater than 45°
many explanations for these losses • An angle within these parameters, minutes later, at 2320:35 UTC, the final data
of control, including factors related to but at an inappropriate speed for the recorded by the Flight Data Recorder (FDR)
the environment, the equipment and flight conditions. showed the aircraft at a rate of descent of
the crew, and a large portion of them 8400 ft/minute (approx. 143 ft/second), a
can be attributed to environmental Source: 2008 Transportation Safety Board of Canada radio altitude of 118 feet, ISIS airspeed of
(TSB) report quoted in the accident report. It involved
factors that cannot always be avoided an inflight upset on an Airbus A310 and highlights the 132 kts and an Angle of Attack (AoA) of 50°
or controlled. possibility of loss of control associated with unusual up. The crew never got out an emergency
aircraft attitude.
message.
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