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fantom
16th Mar 2017, 17:48
How do you protect the aircraft from salt water?

Dougie_diesel
16th Mar 2017, 17:58
Paint and regular fresh water cleaning.

Uplinker
17th Mar 2017, 12:09
The ground crew of an SAR helicopter I flew with many years ago for a TV event sprayed the helicopter all over with something after the sortie. I can't remember the name of the substance now but it was a WD40 equivalent - water dispersing and corrosion protection fluid.

onetrack
17th Mar 2017, 14:09
Salt-X and SaltAway are just two commercial, salt-removing products for marine use. There are no doubt more. Whether these products are approved for use on airframes is not something that I can advise.

john_tullamarine
17th Mar 2017, 22:33
but it was a WD40 equivalent

Careful. It is not generally understood outside the engineering fraternity that such fluids can have adverse effects if sprayed about without engineering consideration and approval.

In particular, many fixing items on a structure (eg higher strength nut/washer/bolt assemblies) rely on torque settings to achieve their intended purpose. It can transpire that some of these water dispersants may have an adverse effect on the torque values of a structural fitting with undesirable structural consequences.

Message - if it's not approved in the relevant maintenance documents such use needs to be referred back to the OEM or DERs for approval.

avionimc
18th Mar 2017, 01:07
John T, thanks for your explanation. Would ACF-50 or Corrosion-X, both approved for use on aircraft, also affect torque values?

megan
18th Mar 2017, 01:12
The Navy used some fluid which we pilots called WD40. Whether that's what it was, or some other propriety fluid have no idea, as that was all in the hands of the maintenance troops.

chw
18th Mar 2017, 01:31
Do not use WD40 it cracks plastics over time WD 40 is a lubricant.
When the inside of a connector is sprayed with WD 40 and reconnected contacts will have a higher resistances, its like having oil on your contacts.

Spray ACF50 in your connector and there will be very little change in the resistances of the connection .

Protecting the inside of a connector should be don with DC 4 compound , the outside of a Cannon plug can be protected with ACF 50.

DaveReidUK
18th Mar 2017, 10:01
Do not use WD40 it cracks plastics over time WD 40 is a lubricant.

WD-40 isn't, and is not intended to be, a lubricant. Its intended purpose is water displacement, hence the name,

megan
18th Mar 2017, 11:13
WD-40 isn't, and is not intended to be, a lubricantWhat the manufacturer says.While the “W-D” in WD-40 stands for Water Displacement, WD-40 Multi-Use Product is a unique, special blend of lubricants. The product’s formulation also contains anti-corrosion agents and ingredients for penetration, water displacement and soil removal.

While WD-40 Multi-Use Product it is not a grease, it is formulated with strong lubricating oils and other ingredients, and is a terrific product to use for bike maintenance. It does not attract dirt or moisture to metal surfaces – just be sure to wipe off any excess WD-40 Multi-Use Product before riding.

For long-term lubrication and other specialized bicycle maintenance needs, check out WD-40 BIKE. Developed specifically for cyclists and mechanics, this high-performance line of bicycle care products is sure to become a mainstay in the toolboxes of bike mechanics for decades.Due to its low viscosity, WD-40 is not always the preferred oil for certain tasks. Applications that require higher viscosity oils may use motor oils. Those requiring a mid-range oil could use honing oil.

Originally designed to be used by Convair to protect the outer skin and, more importantly, the paper-thin balloon tanks of the Atlas missile from rust and corrosion. These stainless steel fuel tanks were so fragile that when empty they had to be kept inflated with nitrogen to prevent them from collapsing. WD-40 was later found to have many household uses and was made available to consumers in San Diego in 1958.

avionimc
19th Mar 2017, 00:41
WD40 should not be used on aircraft. It will eventually cause corrosion.

Instead, use LPS1, 2 or 3 from LPS Labs.

westhawk
19th Mar 2017, 12:18
A short summary on corrosion control based upon my own experience and schooling:

For effective corrosion protection, any accumulated salt should be removed as soon as practical following flight. This is best accomplished by flushing all exterior areas of the aircraft with clear fresh water. Protect air data probes and other water-sensitive components I/A/W the MM instructions regarding aircraft washing prior to flushing. Dry the aircraft. That takes care of removing salt from the aircraft exterior.

The importance of salt removal cannot be overstated. In aluminum skinned aircraft left with salt on the metallic surfaces and fasteners, salty water is an almost ideal electrolyte for several types of electrolytic corrosion, particularly where dissimilar metals interface and between faying surfaces like lap joints. (remember the Aloha Airlines pop-top 737?) Corrosion cells can grow very quickly and cause severe damage in a relatively short time.

Removal of salts from the equation drastically reduces the speed at which corrosion oxidizes the materials. Nothing stops corrosion entirely. Even the most vigilant care and the most advanced protection materials cannot stop it entirely. At best, the rate can be slowed to an acceptable level. NASA, the US Navy and numerous other agencies and universities around the globe have published scads of scientific studies while manufacturers have invested heavily in developing materials and practices to reduce the impact of corrosion on the useful life of aircraft structures.

One critical aspect of corrosion control is regular inspection of protective surfaces like the paint and any sealing compounds. This applies to airframes and engines as well as all their respective components likely to be exposed to salt water incursion. Any breaches of protective surfaces should be inspected for developing corrosion and repaired in a timely manner before restoring the protective surface to a state of effectiveness.

Turbine engines may require more frequent compressor washes, depending on exposure level. Seaplanes operating on saltwater and certain offshore helicopter ops may require hours of corrosion mitigation work each day between rinsing, inspection and any necessary protective compound application. The bottom line is that salt removal and protection application when operating in a saltwater environment is a daily activity in most conscientiously run operations. The frequency of inspection and lubrication activities on the whole aircraft and most of it's components must be increased according the frequency and intensity of salt exposure. The inspection schedule approved for the airplane becomes entirely insufficient in a high salts operating environment.

The application of corrosion protective compounds is widely considered to be most effective when applied to clean, dry and salt-free surfaces. But that has never stopped operators from looking for shortcuts! And it usually costs them much more in due time. Use only manufacturer approved protective materials, or risk doing more damage than you prevent.

I just had to comment on this subject too.
Don't use petroleum based products to clean canon-type electrical plug connectors without manufacturer approval. Some of them eat the sealing and/or insulating material inside the plug. There are specifically designed and approved products for cleaning the connector pins and receptacles, both mechanical and chemical.

fantom
19th Mar 2017, 12:25
Excellent, thank you all.

I posted the question thinking of the light float aircraft that can be hired at Vancouver but I can't think they go to all that trouble to clean them every day, can they?

TowerDog
19th Mar 2017, 12:56
I flew sea planes in salt water.
Corrosion is a big deal. We took it out every day to rinse and service it.
With heavy spray 16 times a day from take offs and landings salt get everywhere, including places you cannot inspect and rinse daily.
Made me nervous to see a flap bracket get thinner every day.
Those planes were made for fresh water lakes in Canada, not salty Carribean waters.
A few years after I left the company the same plane came apart killing everybody.
DHC-6-300. RIP

Pugilistic Animus
20th Mar 2017, 07:19
Though I can't recall the exact details another sea-based aircraft that crashed...Corrosion

Chalk Air (had to Google it

onetrack
20th Mar 2017, 09:20
Chalk's Ocean Airways Flight 101 crash (a Grumman Mallard G-73T) was not caused specifically by corrosion, but by a crack in a stringer in the wing that was never repaired properly. The crack propagated to total wing separation in flight.

However, after the remainder of Chalk's Grumman Mallard aircraft were grounded, unacceptable corrosion was found in a number of their grounded aircraft. Sub-standard repairs on the aircraft were also noted.

Chalk's Ocean Airways Flight 101 crash - Dec 19, 2005 (https://en.wikipedia.org/wiki/Chalk's_Ocean_Airways_Flight_101)

Less Hair
20th Mar 2017, 10:27
During the Berlin Airlift 1948/49 the British contributed their Short Sunderland flying boats operating from Elbe in Hamburg to Havel river in Berlin to transport goods into the soviet blockaded West Berlin. Especially salt as the RN aircraft were protected against seawater and could better withstand salt as cargo.

What did they do to protect them? Is this just WD-40 like some greasy oil cover you put on any metallic surface?

Sunderland unloading salt at Berlin:
http://www.flying-tigers.co.uk/wp-content/uploads/2016/06/S23-RAF-201-Sqn-Short-Sunderland-moored-on-the-Havel-near-Berlin-unloading-salt-during-the-airlift-1948-.jpg

fantom
20th Mar 2017, 20:32
T dog best wishes from Fintas 12A3

Pugilistic Animus
20th Mar 2017, 22:01
Thanks for the clarification OneTrack

NutLoose
20th Mar 2017, 22:13
The military equivalent of WD40 is PX24. When I was serving on Wessex the Royal Navy used to wash and WD40 their Wessex both externally and internally every 28 days if I remember correctly. They used WD40 on them and not PX24 which I always thought was odd. WD 40 I was told stood for Water Dispersant ( effective for ) 40 days after which it attracts moisture, hence the Navies regime. I treat our aircraft with ACF 50 although we do not fly in a marine environment, damned good stuff.

As for washing, just look at the Nimrods, they used to taxy through a fresh water washing bay after they landed.. This is a P3 Orion going through a US one when taxying in.

http://www.navair.navy.mil/index.cfm?fuseaction=home.PhotoGalleryDetail&gallery_id=48

NutLoose
20th Mar 2017, 23:02
http://www.southernlubricants.co.uk/aqadmin/media/uploads/533d42eeed74c/Ambersil%20Px%2024.pdf

Chu Chu
21st Mar 2017, 00:18
I'd have to guess that the Sunderlands were designed from the ground up to be more tolerant of salt. Things like avoiding contact between dissimilar metals where possible, using more corrosion-resistant alloys, avoiding closed areas of the structure that can trap salt, etc. None of that could completely prevent corrosion, of course. But if it came down to something sprayed on, they could have just loaded the salt in a C-54 and sprayed it afterward (and/or before).

Nonni777
21st Mar 2017, 15:32
WD40 or any other such product will not have any effects of any kind on the torque values of a fastener that has already been tightened.

DaveReidUK
21st Mar 2017, 16:46
It won't make any difference to the torque previously used to tighten the fastener, but it sure as h*ll will reduce the torque needed to release a rusted thread - that's the whole point of penetrating oil (though there are products that do that much better than WD-40).

Nonni777
21st Mar 2017, 17:52
I was just looking at one of the comment above about being careful where you spray because of torque values. I agree that there are certainly better products than WD40 available.

9 lives
21st Mar 2017, 20:48
It can transpire that some of these water dispersants may have an adverse effect on the torque values of a structural fitting with undesirable structural consequences.

If the threaded fastener is disassembled, and the water dispersant liquid allowed to coat the threads before they are torqued. In that situation, the threads must be clean and dry before torquing for assembly. This is because some means of torque measurment require predicable friction during assembly, and the lubricating properties of the water dispersant would result in wrong torque values, and probable over torquing. Otherwise, for assembled and undisturbed fasteners, the water dispersant will not affect correct torquing, if undisturbed.

ACF-50 is a well respected product. I know a salt water seaplane operator who, after much study, has chosen Ardrox AV 15.

msbbarratt
21st Mar 2017, 21:19
I'd have to guess that the Sunderlands were designed from the ground up to be more tolerant of salt. Things like avoiding contact between dissimilar metals where possible, using more corrosion-resistant alloys, avoiding closed areas of the structure that can trap salt, etc. None of that could completely prevent corrosion, of course. But if it came down to something sprayed on, they could have just loaded the salt in a C-54 and sprayed it afterward (and/or before).

They might have used magnesium for cathodic protection, much as ships use zinc for the same purpose. However, casting a casual eye over https://en.wikipedia.org/wiki/Galvanic_anode suggests that there's rather more to it than just slapping a few bars of magnesium all over the airframe; there's a risk of hydrogen embrittlement, which would be just as bad for an airframe as salt corrosion.

I recall what a friend told me about the effort to get Apaches operating from RN aircraft carriers; they had to seriously beef up the ships' freshwater generating plant so that they would have enough to wash down the aircraft adequately afterwards. Such as the problems of putting an airframe not designed for maritime operations anywhere near salt water...

Years of bitter experience fighting the rot in airframes put the RN of magnesium alloys for good, and there was much sucking of teeth from the older hands when it was suggested it would be good to fly Apaches from their decks. An old chum of mine used to be a RN photographer, and for yonks his job was taking pictures of hard-to-access recesses of airframes and sending the photos of ugly growths of corrosion back to the factory for assessment. Often as not the assessments came back as "Do not fly. Ever. Again", or words to that effect!

Duxford's just over the way from where I live - I'm now curious to take a look at their Sunderland to see if there's anything obvious! But I suspect that the tricks they used then are pretty much the same as are used these days for carrier aircraft, which are pretty much as you yourself outlined.

riff_raff
22nd Mar 2017, 04:52
Been a while since any new sea planes have been produced. However, there has been much effort made to improve corrosion protection of aircraft used in marine environments. For example, fasteners removed/re-installed during routine maintenance are made from corrosion resistant alloys like A286 cres or 718 inconel. Aluminum structures are anodized/primed/painted/sealed to provide corrosion protection.

Less Hair
23rd Mar 2017, 09:14
OT: How are cars (with all their aluminum parts) treated against corrosion by salt on the roads these days?

Uplinker
25th Mar 2017, 18:47
..........but it was a WD40 equivalent

Careful. It is not generally understood outside the engineering fraternity that such fluids can have adverse effects if sprayed about without engineering consideration and approval.


I thought I had been quite careful John? If you read my full post again I made it quite obvious that I did not know exactly what the substance was. By saying it was a WD40 equivalent, I meant a product that dispersed water and protected against corrosion like WD40 does, NOT that it was actually WD40.

Perhaps I should have used 'type of' or 'sort of' in place of 'equivalent' ?

Whatever the SAR ground crew used that day, (and we are talking about the 1980's here), it was dispensed from about 10L sized cylindrical containers that were pressurised, and the substance was sprayed on through 3' long spray lances.

No Fly Zone
28th Mar 2017, 20:36
For those involved with sea-exposed airplanes of any type, this is import. Heck yes. I di not drive a seaplane, but in past decades have 'landed' a few++ on fresh or brackish water. Protecting you airplane (floats or hull, per type) is critical. If one listens with care, the details are included in basic training.
1. After Every water landing, wash or rinse as much as possible.
2. At home, wash even better.
3. Especially with a Wet Hull Airplane, no matter where moored or parked, get it OUT of the water as often as possible, inspect, INSPECT again, and then repair even the hint of a hull defect. Clean and paint the contact surfaces as necessary - and never delay or compromise anything.
4. It may well fly just fine, but if the SOB floods, your 'flying boat' will sink, often faster than you can drain it or get it into the air. How many times have we heard these horrible tails?
5. STCs are available for most, to install an in-flight water dump. Not a bad idea, but make sure that it actually works and that the water hits the dump when CG is correct.
6. Keep it CLEAN! Did I already mention this? That means inside and especially outside. Over ten years, expect to spend a LOT more on cleaning and paint than do most aircraft owners. This expense will vary, but it you park in salt water, expect to clean and repaint every other year - at best.
Aquatic - hull or floats - is great fun. It also requires considerable skill and some extremely serious attention to maintenance.