Horstroad
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MD82 Yellow Triangles On Wing

Wed Sep 19, 2012 4:38 pm

what are these yellow triangles with the red string on the inboard wing of the MD82 good for?


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[Edited 2012-09-19 09:38:35]
 
AAR90
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RE: MD82 Yellow Triangles On Wing

Wed Sep 19, 2012 5:27 pm

Helps with spotting clear ice on top of wing during ground inspections (i.e. pilot pre-flight walk around).

I haven't been on the MD80 for many years, but when I was flying it these were installed as AA was encountering clear ice formation even on clear days (at the airports) due to cold-soaked fuel. Pre-flight walk around including climbing a ladder and using a long pole to physically move the red rope. If it didn't move freely, you probably have clear ice on the wing that is otherwise very difficult to see.
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Horstroad
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RE: MD82 Yellow Triangles On Wing

Wed Sep 19, 2012 9:11 pm

I have never seen it on any other aircraft. why does only the MD80 have it (or am I just blind?)
 
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larshjort
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RE: MD82 Yellow Triangles On Wing

Wed Sep 19, 2012 9:43 pm

Quoting horstroad (Reply 2):
I have never seen it on any other aircraft. why does only the MD80 have it (or am I just blind?)

Because the MD-80 have a bad history with clear ice on the wings, see SK751.

/Lars
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AAR90
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RE: MD82 Yellow Triangles On Wing

Thu Sep 20, 2012 4:20 am

The MD80 series have relatively thin wings. Fly relatively long flights and the underlying structure of the wings along with the fuel get "cold-soaked" more than most other airliners. After landing, that cold surface stays cold for a longer time period than most other airliners and.... any moisture in the air can (and does) form clear ice on the wing. Additionally, the MD80 fuel tanks do not contain any heat exchangers (oil or hydraulic cooling using fuel tanks is common in airliners). The inner wing surface is directly in front of the engines so any ice that forms and then breaks free has a high probability of causing engine problems. Hence the increased ground procedures to check for clear ice on the wing... especially the inner wing area. The triangles/rope simply assist in the inspection process.

Alternatively, AA helped develop a "heater blanket" that was installed on AA MD80s along the upper wing surface which is supposed to prevent or at least minimize clear ice build-up in that area. Doesn't eliminate the inspection, but greatly reduced the occurrence of ice and subsequent costly deicing on moderately (mid-50 degree) days.

The MD90s I flew (ex-QQ) had a fuel recirculating system that took 20% of the pre-heated fuel from just before the engine fuel control (heated by oil and proximity to hot engines) and returned it to the fuel tanks. That kept the fuel tank temps high enough (whenever the engines were running) that there was never a problem with the MD90 "making ice." Never retrofitted to MD80 series... probably due to costs. It worked great though!
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my235
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RE: MD82 Yellow Triangles On Wing

Thu Sep 20, 2012 5:48 am

Quoting AAR90 (Reply 4):
AA helped develop a "heater blanket"

I remember being on an Alaska MD-80 heading to ANC from SEA in 2007. The heater blanket circuit breaker had to be replaced while we waited. It was my first time to SEA so I was happy for the delay.  
 
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HAWK21M
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RE: MD82 Yellow Triangles On Wing

Thu Sep 20, 2012 6:21 am

What is the MEL despatch requirements for broken/missing strings.......
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atlamt
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RE: MD82 Yellow Triangles On Wing

Thu Sep 20, 2012 10:13 am

Quoting HAWK21M (Reply 6):
What is the MEL despatch requirements for broken/missing strings.......

If I remember correctly you could have one missing and dispatch with a MEL.

At DL the strings have been removed. The upper wing surface in the area where the clear ice could form has been coated with a rough texture surface coating. A long pvc pole is rubbed in the area, if any ice is present you won't feel the rough surface. Unlike the strings which provide localized detection the coating protects the entire area and the coating can't blow away.
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AAR90
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RE: MD82 Yellow Triangles On Wing

Sat Sep 22, 2012 12:38 am

Quoting HAWK21M (Reply 6):

What is the MEL despatch requirements for broken/missing strings.......

AA also replaced the rope with textured paint outboard of the overwing heater "blanket." Current MEL says 50% of the painted stripes may be missing. When I flew the plane (20+ years ago) AA was just installing the triangle/rope setup and any/all could be missing.
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HAWK21M
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RE: MD82 Yellow Triangles On Wing

Thu Sep 27, 2012 6:21 pm

Quoting atlamt (Reply 7):
If I remember correctly you could have one missing and dispatch with a MEL.
Quoting AAR90 (Reply 8):
When I flew the plane (20+ years ago) AA was just installing the triangle/rope setup and any/all could be missing.

Would have a weather related condition too I presume...........
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EireRock
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RE: MD82 Yellow Triangles On Wing

Tue Oct 02, 2012 1:43 am

Quoting HAWK21M (Reply 9):
Would have a weather related condition too I presume...........

SAS also have the heater mats on their MD's and when they are dispatched under MEL the aircraft must have a physical clear ice check at each turnaround, subject to certain conditions I presume although I have completed these checks on fine summer evenings.
 
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HAWK21M
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RE: MD82 Yellow Triangles On Wing

Sat Oct 06, 2012 7:08 pm

Quoting EireRock (Reply 10):

SAS also have the heater mats on their MD's and when they are dispatched under MEL the aircraft must have a physical clear ice check at each turnaround, subject to certain conditions I presume

The good thiong about Maintenance out here,is that De-Icing is never needed almost 98% of the time....  
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