jul-aug2012

26
FEATURE
Flying operatiions
If not then, why did he not take over when the
localiser was intercepted, late, at a tight 5.5nm
and 2000 feet?
When I flew into Schiphol, I recall that the
approach controllers preferred a quiet, idle
thrust, constant descent, approach with little
or no chance for a level period to comfortably
capture the glide slope, especially approaching
from the north and east of the airport. That’s
how it was more than ten years ago.
It is a common occurrence around the world
for an aircraft to be vectored too close and too
high to the runway, forcing the glide slope to
be captured from above. The steep descent,
on a non-precision approach, adds to a crew’s
already high workload.
Automatic flight systems, such as autopilot
and autothrottle, increase fuel savings, reduce
crew workload, and give more opportunity
for situational awareness, but may also make
pilots too complacent, too comfortable, lazyminded,
and out of practice when hand-flying
becomes necessary. Underlying systems
malfunctions could be masked, especially when
the crew lacks a complete understanding of the
automated systems’ interactions. Automation
can set deadly traps for a crew not on top of
their game.
To this add training that is perfunctory and
uninspiring, that is inadequate, outdated, and
lacking standardisation between one instructor
and the next. Combine it with non-existent
or poor CRM, and watch the problems in the
cockpit swell.
Turkish Airlines TK1951 crash site
We know from the accident report that the radio altimeter gave the autopilot
false information. This forced idle thrust and, uncorrected, led to the stall. But
this accident was completely preventable, had the captain taken control and
manually flown the approach.
At what point would it have been prudent for the captain to take physical
control of the aircraft? In the performance of his pilot monitoring duties, the
captain was not proactive in his support of the first officer, who was pilot
flying. Was the captain too comfortable with his first officer’s handling of
the aircraft, the fact the weather was not too threatening and that the aircraft
was being flown on autopilot? Did he just assume, because the approach
procedure was one he had done a hundred times before, that there would
be no drama that day? We have all fallen into that trap, regardless of how
disciplined and professional we think we are.
Had the captain been vigilant, as he was supposed to be as pilot monitoring,
had he been calling out the flight mode annunciations on the primary flight
display (PFD), and monitoring engine instruments, such as abnormally low
N1 (low-pressure compressor rpm) and fuel flow, he would have immediately
realised that there was something abnormal about the profile and the aircraft’s
automation. (Editor’s note: See the feature article in Flight Safety Australia
March-April 2012 for a discussion on the difficulties and poor definition of the
pilot monitoring role.)
Typically, when I was flying the Boeing 737NG, on final approach, after gear
down and flaps 15, I would call for ‘flaps 30 - landing checklist’ at about 1300
feet. I would let the aircraft re-stabilise, disengage the autothrottle, checking
that N1 was approximately 57 per cent, then disengage the autopilot and
hand-fly the approach from 1000 feet to landing rollout. Maybe this technique
allowed me to dodge the bullet that brought down TK1951. Maybe I was
just lucky.
As a pilot, I would like to get something out of every flying day that reminds
me I am still a pilot. Taking manual control of the aircraft to hand-fly is a rare
opportunity that I really enjoy, whether as captain or first officer. It is also
an opportunity to refresh my hand-flying skills, which I may still need for
a visual circuit when the autopilots have failed, or if I have a simulator
proficiency check.