Re: How much "rust" is tolerated and landing light question?

Date:         13 Oct 98 02:48:29 
From:         stevec01e@aol.com (STeveC01e)
Organization: AOL http://www.aol.com
References:   1
Next article
View raw article
  or MIME structure


>This implied some corrosion to me. Now my questions.  Did I actually
>see rust and are steel cover plates used?

Possibly not.   Some grease, i.e. Mobil 28, can have the appearance of rust
from a distance.  I've even heard mechanics tearing apart some structure for
inspection and the "problem" turned out to be grease.  Flap tracks and
actuators are known for spitting out grease everywhere.
    If you were looking at a patch, then I do NOT expect it to be made of steel
but rather aluminum, however, I admit I'm not familiar with that a/c and
structure.  I would rule out composite material.   Its possible they coated the
part, possibly with grease.
    Aluminum is more susceptible to salt environment---that is, bare, untreated
aluminum.  That is why most aluminum structure is primed/sealed with zinc
chromate(green) and/or painted OR it is annodized.   If there was steel used on
the wing skin or flight controls surfaces, I would expect it to be thin
stainless steel.

RE: > I notice a hole in the starboard wing root where a landing
>light lens used to be.
>or decided to fly  anyway?

   If this was a landing light, then the crew can not fly without it UNLESS it
is so address in the Minimum Equipment List(MEL).  If the MEL says one can be
INOP, then and only then will the crew knowingly fly the aircraft without it.
    I can't address what would happen to the stucture due to the airloads
against it, but I doubt the plexiglas was considered in the stress calculations
of the wing's strength.  Maybe it would "kill" a portion of the  lift
component.

Steve Cole