I experienced a trim runaway on my Europa which left me with
similar questions about handling the resulting problem.
My trim system is non-standard, with the trim switch mounted on
the stick. In addition, I have a switch on the panel with
FAST/OFF/(SLOW) trim selection, where the SLOW is momentary
contact and must be held to activate SLOW speed trim.
Similar to Martin Tuck's prior description, my Europa trims solo
with the indicator at 2-3 divisions of down indicated.
A trim failure occurred when I blipped down trim with the panel
switch set in FAST mode. The result was a LOT more down than I
expected. Fortunately, I had thought through handling this
situation and quickly put the panel switch to OFF. This left me
with far more down trim than was comfortable but at least it
wasn't at full down or increasing since I had reacted quickly.
I explored the feel of the miniature dpdt momentary switch which
had failed and it felt like it was still working but that it
wasn't automatically centering any more. Per my emergency
situations checklist I set this switch for UP trim and then
blipped the panel switch to FAST. The trim moved in the UP
direction as desired so I decided things were OK and gave it
another blip which took it farther than desired into UP trim.
So, I moved the trim switch to the DOWN position and blipped the
panel switch again -- this time with no response: the trim switch
had now failed completely.
The result was that at cruise speed considerable down force was
required to maintain level flight. I slowed to about 70kt which
made the force manageable but still undesirable for a novice
Europa pilot.
On landing, the trim required holding very noticeable down force
to maintain 60kt. With no prior experience landing while holding
firm down, I bounced the landing and made a go-around.
Apparently, I learned enough from that: the second landing had
only a minor bounce.
I learned several things from this experience. First, be careful
what you wish for -- I would have been better off after my first
post-failure trim adjustment had I then landed; wishing for the
second up adjustment was clearly an error.
Second: I suspect that a trim failure in my Europa in which full
up trim resulted might be beyond my present capability. In this
situation, the indicator was at about 1/2 division down when I
landed, fairly far from full up.
Third: I was considering changing the trim speed switch so that
it could be left in the SLOW position. This would have required
that I carefully move it to the middle position to turn trim
power off. As it was, I simply slapped it toward the down
position which turned it off quickly with no fiddling needed.
Fourth: I want a VERY good quality switch on the stick for trim
control. The failed switch was of unknown manufacture; an
internal plastic part failed.
Fifth: Any roll trim system must be incapable of runaway (see my
note on a very simple manual roll trim)
John N44EU
----- Original Message -----
From: "Garry Copeland" <garrett.copeland@ukgateway.net>
Subject: Aileron and elevator trim
> Since the Europa elevator trim (or aileron trim if fitted) has
no manual
> back-up, I am curious as to how controllable the aircraft is
with a trim
> runaway to the limit stop.
> Has anyone ever experienced a trim runaway or uncommanded
movement to the
> trim limit (aileron or elevator)?
> Can a Europa be safely flown to a landing in that condition?
>
> Garry Copeland
>
>
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