Flap mass balance corrosion

Any DA40 related topics

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Colin
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Re: Flap mass balance corrosion

Post by Colin »

Lance Murray wrote:Seems that they don't care if their airplanes last beyond 10 years.
I agree with this. The bubbling by the screw heads on my wings is very bothersome and I know it means the wings need to come off and a bunch of work will need to be done and I feel like the littlest bit of common sense about that corrosion issue would mean all these planes would not need those hours and hours (and thousands and thousands of dollars) of work done on them.

Bums me out.
Colin Summers, PP Multi-Engine IFR, ~3,000hrs
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N972RD DA42 G1000 2.0 s/n 42.AC100 (sold!)
N971RD DA40 G1000 s/n 40.508 (traded)
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Lance Murray
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Re: Flap mass balance corrosion

Post by Lance Murray »

Collin,

Both of my airplanes have this problem. I'm in San Diego. Maybe when it is time we could get someone to do both planes at the same time.
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Colin
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Re: Flap mass balance corrosion

Post by Colin »

Lance,

I am leaning toward having the shop on the field at London, ON do it this summer, because I could have the factory replace the canopy at the same time. There is crazing on my canopy and it has started to bother me a little more. Getting a little extra headroom would be nice, too.
Colin Summers, PP Multi-Engine IFR, ~3,000hrs
colin@mightycheese.com * send email rather than PM
http://www.flyingsummers.com
N972RD DA42 G1000 2.0 s/n 42.AC100 (sold!)
N971RD DA40 G1000 s/n 40.508 (traded)
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Lance Murray
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Re: Flap mass balance corrosion

Post by Lance Murray »

Here is an explanation of the problems that we are having.

All of our Diamond Stars are doomed due to improper engineering?

http://www.boeing.com/commercial/aeroma ... rrosn.html

Carbon Fiber and Aluminum are NOT comparable and the interaction causes galvanic corrosion.

"Fiber-reinforced plastics are corrosion resistant, but plastics reinforced with carbon fibers can induce galvanic corrosion in attached aluminum structure."...."For example, graphite fibers, which are used to reinforce some plastic structure, present a particularly challenging galvanic corrosion combination. The fibers are good electrical conductors and they produce a large galvanic potential with the aluminum alloys used in airplane structure. The only practical, effective method of preventing corrosion is to keep moisture from simultaneously contacting aluminum structure and carbon fibers by finishing, sealing, using durable isolating materials such as fiberglass, and providing drainage. Figure 14 shows the 777 carbon fiber-reinforced plastic (CFRP) floor beam design and corrosion-protection methods. An aluminum splice channel is used to avoid attaching the floor beam directly to the primary structural frame."
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Tim H
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Re: Flap mass balance corrosion

Post by Tim H »

Great info Lance.

Do the DA20, DA40 and DA42 share the same airframe construction (material, paint, etc..)? If so, the DA20's may provide some fleet leader experience. They have been around longer and probably been sitting outside in training enviroments.
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TomO
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Re: Flap mass balance corrosion

Post by TomO »

For anyone interested, the part number for the flap arm balance is DA4-5751-00-62MOD.

I also could not find the part in the IPC or in the maintenance manual.

Brittany at Premier Aircraft at KFXE had the part in stock and also confirmed its elusive nature in the Diamond publications.
Apparently they replace them fairly often due to corrosion.
My corrosion also appeared quite rapidly.

I will leave it to the mechanic on how he will replace the flap arm (removal of flap,through the access holes ,etc).
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jwx96
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Re: Flap mass balance corrosion

Post by jwx96 »

I’m seeing a little corrosion on the leading edge of the MLG. They may have to be repainted this year. Last year we repainted some of the access panels on the under surface of the wings.
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