FLIGHT MANAGEMENT COMPUTER FAILS 37,000FEET
BY CEO TOM WEST
O
ne bright
morning
on Aug
13th 2016 sitting
on the tarmac
at HartsfieldJackson Atlanta
International
airport (KATL)
all things seem
to be normal in
the B737x. All
102 passengers
boarded without
delay. During the
pre-flight checks,
everything was a
go. We pushed
back from the gate
with 14,747 pounds
of fuel onboard.
Flight planning
was completed
using Sky Vector;
our route will be
IRQ337043 EVING
Q60 JAXSN
DORRN CAVLR3
ARRIVAL KIAD.
Flight UAA0001
Taxing to runway
26L number six
in line for takeoff.
While waiting for
takeoff clearance
from VATSIM
controller, First
Officer noticed
the flickering of
FMC displays. The
decision was made
to continue the
flight if all systems
was a go when it
was our turn to take
off. After waiting
for five minutes
tower gave us
takeoff clearance.
Once again, the
Captain and First
Officer looked over
the instruments.
All systems were a
go with no faulty
indications. After
takeoff, we climbed
to our final altitude
of 37000ft. Three
hours into the
flight over the
LOOEY VOR we
experienced a
duel FMC failure.
With only having
our primary
instruments,
we had lost all
capability of
navigating with the
onboard FMC. We
managed to use the
onboard charts to
finish our flight and
to land safely at our
final destination
Washington Dulles
International
Airport.
N
ow from
the story
you just
read you can see
how things can go
bad if you are not
expecting anything
to go wrong. If you
are flying in the
air and should an
emergency arise,
you should be
prepared to handle
it. Lets say if we
did not have charts
onboard and the
above situation
happened what
could you have
8| FlyUAA| www.FlyUAA.org| September Issue
done. Primarily, if
you were flying on
VATSIM in a controlled airspace we
would want to let
the controller know
what is going on. If
the airspace is not
being controlled it
is very important
to monitor Unicom
122.8 for incoming
traffic. In this case
where you have a
duel FMC failure
you would check
your circuit breakers and then resume
by using conventional navigation.
Therefore, if we had
no charts onboard
you would have to
convert your IFR
flight to VFR and
hope the weather
meets VFR conditions. As we covered in last month’s
issue when flying
VFR you have to remain 1000ft above
the clouds, 500ft
below the clouds
per 10000ft altitude
and the golden
rule you cannot fly
through any clouds.
As you can see,
you do not have
that many troubleshooting steps for
a failed FMC. 9
times out of 10, you
can always get the
FMC to reset itself
in flight by resetting
the CBs.