Re: Little red strips of fabric on the wing????

From:         ehahn@fairlite.mitre.org (Ed Hahn)
Organization: The MITRE Corporation, McLean, Va.
Date:         24 Feb 94 23:40:43 PST
References:   1 2
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In article <airliners.1994.954@orchard.Chicago.COM> "Dr. Martin Erdelen" <HRZ090%DE0HRZ1A.BITNET@vm.gmd.de> writes:


   On 16 Feb 94 01:10:32 PST Karl Swartz said:
   >>On a recent US Air flight the aircraft had 4 or 5 strips of 1" wide cloth
   >>type material (~12" long) attached to the wing, about 2' from the fuselage.
   >
   >This was an MD-80, or perhaps a DC-9, right?  If so, these were added
   >after the SAS crash several years ago.  The problem is that the fuel
   >tank arrangement on the MD-80 has a tendency to create wing icing
   >problems even in conditions where one would not normally expect to see
   >any icing.  The cloth strips are there to help make the ice visible.
   >
   Karl, would you elaborate, please? To my (layman's) ear this sounds rather
   bizarre in the (supposed) high-tech age:
   - What kind of cloth do they use? There must be quite a bit of wear
     (and tear?) on it...
   - How is it fixed to the wing? (I love the idea of it merrily fluttering
     in the (500 knots or so) wind, but probably this isn't the case.

----
They are cords, and are part of an Airworthiness Directive from the FAA
after several wing ice ingestion incidents.  Yes, they do flutter
"merrily" in the breeze.  AD's must be complied with, or the aircraft
isn't airworthy.

However, because, as you stated, it's hard for them to stand up to Mach 0.72+
flight for any significant period of time, they do tend to fall off
after a while.  Which is making many airlines go to an Alternate Means
of Compliance, using a textured paint pattern in the danger area.
Obviously, you'd have to fly a lot faster to make this stuff fall off :-).
----
   - How do they check it? Captain or purser or whoever taking regular trips
     to the cabin to have a peek out the window? (like the time and movie
     honoured way of finding out about oil loss).
----
Actually, the FO is supposed to catch it on his walk around.
Maintenance crews will also check it before leaving the gate area.

Because the ice is caused by supercooled fuel in the wings, it usually
forms pretty quickly while on the humid ground, and would be caught in the
walkaround.  However, the AD was issued so that IF the crew had to
look at the wing through the window, they could see it was a problem.
----
   High-tech forever...!

   MArtin
----
Actually, if the airlines can find a simple low-tech solution, they
will take it every time.  High-tech usually equals big-bucks -
acquisition and maintenance.

ed

////////   Ed Hahn | ehahn@mitre.org | (703) 883-5988   \\\\\\\\
The above comment reflects the opinions of the author, and does not
constitute endorsement or implied warranty by the MITRE Corporation.
Really, I wouldn't kid you about a thing like this.