klehman(at)albedo.net
Guest
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 Posted: Wed Jan 02, 2013 7:09 pm Post subject: Advisability of using anti-corrosion lubricant on contacts. |
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Below is an interesting read and the first time I've seen legitimate
cautions against using corrosion-x type products too liberally. I've
never seen a problem with it myself and have been a big believer in the
product.
Ken
AIRWORTHINESS BULLETIN
Corrosion Inhibiting Compounds and Effects
on Aircraft Structural Joints.
AWB 02-042 Issue : 1
Date : 23 November 2012
Page 1 of 2
1. Effectivity
This AWB is applicable to all aircraft.
2. Purpose
To advise maintainers, registered operators and manufacturers on the
unintended mechanisms that could result when corrosion inhibiting
compounds are applied to aircraft structural joints.
3. Background
A recent study has been carried out into the effects of corrosion
inhibiting compounds (CIC) on aircraft structural joints. The work
formed the basis for a Phd thesis and was funded by CASA. The resulting
outcomes are promulgated in this AWB for the benefit of the aviation
industry.
The study involved identification of common aircraft structural joints
and testing of representative structural specimens in which conclusions
were drawn.
4. Recommendations
• That the use of water displacing thin film CIC can offer substantial
benefits in terms of preventing and/or retarding corrosion. Any change
in the use, frequency or application of these compounds should be done
in close consultation with the aircraft manufacturer before making
changes to the Corrosion Prevention and Control Program (CPCP) for the
aircraft. An approved change should be via Service Bulletin or Letter or
approved as maintenance data under CAR 2A(4).
• Research has shown that the use of CICs on structural joints that rely
on friction/clamp up force and are primarily in shear, such as aircraft
lap joints, may experience a reduction in fatigue life due to the
ingress of CICs on the faying surfaces of the joint. This effect is more
apparent for highly loaded joints where CIC application can exacerbate
relative movement within the joint. The use of CICs on certain lap joint
specimens tested shifted the failure mode from sheet failure to a less
desirable rivet failure mode at higher loading.
Caution should be exercised in applying CIC to aircraft structural
joints known to be highly loaded and/or fatigue critical. Fatigue
critical joints tested in the analysis showed a reduction in fatigue
life of up to half when CIC were introduced. Where a fatigue crack has
been initiated, the use of CICs has been shown to increase the fatigue
crack growth rate.
AIRWORTHINESS BULLETIN
Corrosion Inhibiting Compounds and Effects
on Aircraft Structural Joints.
AWB 02-042 Issue : 1
Date : 23 November 2012
Page 2 of 2
• Careful sheet metal work practices should be followed during the
manufacture and repair of aircraft structures to ensure that the correct
rivet driving (clamp-up) force has been applied during installation.
Rivets that do not meet correct tail diameter specifications (i.e. D/Do
= 1.5) can result in working (smoking) of rivets under normal conditions
and coupled with the application of CICs, may result in joint fatigue
life reduction. Working rivets can lead to premature rivet failure with
a subsequent increase in loading on surrounding fasteners.
• CICs should not be employed (without appropriate demonstration of
safety) in aircraft featuring unusual construction or materials such as
non-metallic structure or adhesives not normally employed in modern
aircraft. Caution should also be followed for the application of CIC
near and around aircraft electrical system wiring.
5. Summary
If CICs are used appropriately they can offer substantial benefits in
protecting aircraft structure however caution should be exercised to
ensure that they are applied in accordance with the manufacturer’s
instructions.
6. Reporting
Aircraft defects should be reported via the SDR system in accordance
with the requirements of CAR Part 4B.
7. Enquiries
Enquiries with regard to the content of this Airworthiness Bulletin
should be made via the direct link e-mail address:
AirworthinessBulletin(at)casa.gov.au
or in writing, to:
Airworthiness & Engineering Branch Civil Aviation Safety Authority GPO
Box 2005, Canberra, ACT, 2601
| Quote: |
<dee.whittington(at)gmail.com>
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| Quote: |
Best product on the market is CorrosionX. You can and should use it all
over. During the 17 years I was Maintenance Manager of a four Cessna club,
we fogged inside the wings, empenage, tailcone, etc. using a special
pressure pot and very long wands . And I used it on all switches and
electrical connecctors. There are competitors on the market, but for my
money CorrosionX leads the pack. www.corrosionvproducts.com Sold by
Aircraft Spruce, Amazon.com and many other dealers.
Dee
On Wednesday, January 2, 2013, bobbarrow wrote:
>
> bobbarrow(at)bigpond.com <javascript:;>>
>
> On my RV7A I decided to instal additional connectors at the subpanel so
> that I could easily remove the whole instrument panel for ready
maintenance
|
| Quote: | > access.
>
> Obviously this has bequeathed me additional contacts. I am now wondering
> whether I should be using some anti-corrosion contact lubricant sprayed
> onto all of those contacts.
>
> Is that advisable, and if so, can some-one recommend a readily available
> dielectric product (brush on or spray on) that will protect the contacts
> against corrosion without damaging the actual plastic connectors.
>
> Cheers Bob Barrow
>
>
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