| by |
T. D. Ponder |
The FAA has just issued an Airworthiness
Directive for Boeing 737 aircraft that
incredibly does not offer to solve known
problems with the aircraft's rudder Power
Control Unit (PCU), but instead mandates
crew training so pilots can attempt to
survive sudden control problems.
NTSB investigators remain unsure why
two Boeing 737s crashed, one near
Pittsburgh and the other in Colorado,
although rudder problems definitely are
suspected. The 737 is the most popular
airliner today with 2,705 flying world
wide, including 1,115 in the U.S.
The FAA mandate requires Flight Manual
changes and crew training to instruct pilots
how to correct jammed or restricted flight
controls.
That's right. The FAA has said that test by
Boeing showed the 737's rudder PCU
under extreme conditions could jam and
even go in the opposite direction desired.
Imagine the fun of that on a gusty landing!
I certainly would call a rudder movement
in a direction opposite from input an
extreme condition at time or altitude.
Is training to overcome a mechanical
uncertainty a viable solution for one of the
worst conditions a pilot could ever face?
The FAA goes on to suggest a pilot lower
the nose in such a situation to increase
airspeed and regain control of the aircraft.
The FAA does not clarify, to my
knowledge, if this procedure is to be used
only at altitude or maybe at Decision
Height on an ILS night IMC approach.
Only a fool would do such a thing to an
aircraft already out of control due to
rudder hardover (sudden rudder
movement) mere feet above a runway.
What? Just slam her down, split the gear,
and maybe walk away saying that is what
I was told to do?
The pilots who fly 737s, the Boeing Co.,
and the FAA have known about these
problems for years. A fellow flight
instructor I gave instruction to in
aerobatics subsequently was hired by
Piedmont (now US Air), and he told me in
the early 1970's that the 737 would get
into a "Roll Oscillation" condition on
approaches under gusty or turbulent
conditions. He said the plane would then
have to be flown manually, with locked
elbows to force the yoke steady, until the
aircraft stabilized.
Other pilots have told friends of
unexpected and sudden rudder hardover
at altitude and said they did not think they
would have recovered had they been on
approach. There was no indication of
problems from the crews involved in the
two approach crashes, so you know it
happened suddenly and that it was
unrecoverable.
If a Cessna or Beech or Mooney had a
problem with the rudder jamming
unpredictably, you can bet the FAA
would ground the aircraft until the problem
was fixed. But because the Boeing 737 is
the world's most popular jetliner — and
the economic impact and loss of public
trust that would be caused by a grounding
order is simply unthinkable — the FAA is
instead imposing upon crew members the
edict to break the FAA's own rules:
namely those rules that require, in terms of
aircraft and airman certification, that no
unusual or extraordinary piloting
techniques or abilities be required. This
A.D. presents a ludicrous position
unworthy of the FAA.
Additionally, a standby procedure is
mandated that requires the switching off of
the rudder's hydraulic assist system under
prolonged conditions and executing
approach and landings manually. Let's
hope lady pilots type rated in 737s have
had their Wheaties before preflight.
It is my opinion that there still exist the
potential for disaster until the actual
problem is solved. Components should be
redesigned, if necessary. The resolution of
this problem belongs to Boeing, the FAA,
and the Air Carriers — certainly not to the
pilots in the cockpit where it is just a little
too late for engineering, or attempts at
aerobatics on short final with a plane full of
paying passengers.
This situation needs to be resolved
immediately before the possibility of lives
being unnecessarily lost becomes a reality.
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