S-tec 55x Roll servo bridle and main spar

Alan Williams · #1 07-02-02, 01:50 AM

In installing our new system recently the sharp ame observed that when the aileron is fully deflected the servo bridle makes contact with the main spar. Not a good situation and the ame would not sign off the work.
Inspection of 3 other similarly equipped aircraft on the field showed the same situation. You should all have a look in the left wing.
S-tec has been cooperative in offering to move my aircraft from Victoria B.C. to Mineral Wells Texas as they can only do the work to amend the STC in their facility. The aircraft will be there within the next two weeks and you can expect the appropriate amendment to the STC shortly thereafter.
It is a good idea if you are equpped with the S-tec system to inspect the roll servo bridle and main spar just for peace of mind.

Alan Williams · #2 07-02-02, 11:14 AM

GMAS; Did you check the servo bridle thread for the S-tec autopilot. I would be very interested to hear your thoughts.

GMAs · #3 07-02-02, 12:50 PM

Yes ... and we made sure it was not hittting... the company is aware of it.. so is our local FAA office... as we brought
it to their attention... you can adjust it so it doesn't hit.. but, that is not the way they want it from the
manufacture... they claim that some do and some don't... but, if they are going to call for your plane to be taken
down and checked... and work done on it... make sure they only modify their system... after all its just like the old
one except for the new'er actuators... the older system came real close also but, it missed by just that much.. and
that was all that mattered...

Keep us posted as to what they found... I am sure it won't be a AD that they will make but, it would most likely be a
service bull... and that won't get to all the people who should be in the know... most are finding out info from web
pages like these.. and if they are on a subscription from each product manufactur... best to just get the word
around...

Now as to the limits... I am sure you will never get to the point where the thing hits in normal flight... but, it does
change the limits and you are told that is as far as it goes... anything less and its interfearance... so it does and it is
...kinda thing...

By the way... you have a good AME... for not signing off anything that is not right... and making it known... we need more of them... as they keep you safe... even though it presents a problem... hope this helps.. GMAs

Alan Williams · #4 07-03-02, 02:07 AM

GMAS: I'll check it out with my shop owner , but I think there is a little more to it than that.
A proper fix requires uncrossing the bridle and reversing the leads to the servo motor which the STC instructs one to reverse on installation.Rather suspicious. This way the brilde runs in the clear which is the way I understood the cessna one ran. That part I will confirm with the shop.