Message-ID: <001101c0407a$417be400$2231143f@oemcomputer>
Reply-To: "dfs" <dfs@gateway.net>
Reply-To: lancair.list@olsusa.com
From: "dfs" <dfs@gateway.net>
To: "Lancair List" <lancair.list@olsusa.com>
Subject: 235 Flap mechanism problem
Date: Fri, 27 Oct 2000 17:58:15 -0700
Mime-Version: 1.0

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Here's a heads-up warning to all you out there flying the older 235's
(or modified 235/320/xxx) with the top-hinged flaps.

Whilst flying a bunch of EAA Young Eagles Tuesday, I noticed a very subtle
change
in the roll trim during changes in flap deployment (going from neutral to
reflex and back again). Only because I sensed something wasn't happening the
way it always had on every other flight was I alerted that something wasn't
right.

I elected to stand down from another flight and put N235SP back in the
hangar for some intensive inspection. What I found turned my blood cold! One
more flight and I probably would have suffered asymmetrical flaps and joined
the "Aftermath" statistics that
show up in every issue of Flying Magazine.

If you are flying an older version of the Lancair with the top-hinged flaps,
there is a pivot-pin at the inboard end of each flap made from a
3/16 in. bolt with the head cut off, that engages phenolic-and-aluminum
bearing
plates glassed to the junction of the fuselage bottom and rear spar .

Upon inspection, I found that the rotational forces on the pin had
un-screwed the outer jam-nut so that the pin was completely loose!! The
outer nut had dropped off completely and the pin wasn't being held in place
at all. In fact, when I found the problem, the pin was just about to fall
out completely. If this had happened, I'm sure I'd have experienced a large
degree of flap non-symmetry - maybe more than I could have controlled with
ailerons. If so, I'd have made a very neat smoking hole somewhere in the
fair city of Coeur D'Alene.

Srongly recommend you'all drop the inspection plate under the flap ends and
take a hard look with a strong light. It can also be observed looking down
from the top behind the seats. the pins are easier to see from the top, but
requires opening the covers over the fuselage cross-shaft just behind the
rear spar. The two nuts on each pin should be tight with the lever of the
flap weldment captured between them. (Easier to see than to describe).

I know that when I installed the pins, I used Lok-tite on the threads - but
mine still came loose! This happened at about 580 hours on the airplane,
just for reference, but since there's so many slight differences in building
techniques, it might happen at any time. I have always had this part of the
flap mechanisms on my "annual" inspection list and did confirm that all was
well last spring, so it came loose since then.

Cheers,

Dan Schaefer

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