Twin Otter Amphibian Operations
 

We are planning to park our amphib DHC-6 overnight in the saltwater sometimes, due to a a lack of a ramp at one destination.

I'd appreciate hearing from anyone with experience doing this, how they operated, special instructions, advice, problems that came up, mitigation.

Thanks very much.

Only flew them Twin Otters on straight floats, but In Salt 100%.
The Amphips may have corrosion problems in the retract mechanism after a few days, especially the electrical connections.
More serious is salt spray getting into the flap/aileron mechanism with severe corrosion to the cast aluminum.
Also salt being blown into the tail plane and empennage where rinse and inspection is hard to do, or not doable expect for major checks.

The Twin Otter I flew on floats in the Caribbean 1984/1985 was converted back to wheels and sold to some Pacific Island operator where it crashed from altitude and killed everybody. Structural or flight control failure was not ruled out,
When I flew it back then I watched the flap brackets get skinnier every month and had bad dreams about the salt being blown into the tail 16 times a day, every day.
(We did 8 round trips between STX and STT every day. 16 landings and 16 take offs every day, flight time only 18 minutes, the Twitter was drenched in salt all day, every day.)
These airplanes was designed for flying on lakes in Canada, no salt, no maintenance..:cool:

Near:

Drop an email to Viking Air or Kenn Borek Air and inquire on if they use a particular program for saltwater ops. I'm sure Viking has some sort of Corrosion Prevention Program that addresses your questions.

If not an option and at a minimum, after your saltwater flight douche the entire aircraft with fresh water to remove the salt residue. Washing with a aircraft soap would be better. Also add a corrosion preventative like Corrosion X to areas prone to holding water like float bays, and reapply on a regular basis.

W1

Drop an email to Technical Services at Trans Maldivian Airways. They are the biggest operator of amphibian Twin Otters.

Big one is to really rinse out the fuel gallery ( ie all the belly panels). Before going into salt, spray the wheel wells and gear actuators with LPS or equivalent. When it gets back home rinse the aircraft, particularly the tail, and the floats with large amount of water and then get in there with soap and brushes. Check float compartments for any water that has leaked in. If you find any remove it and rinse floats. Pull the wheels often and re grease the bearings if you are only going into salt very occasionally I would suggest redoing the bearings after every exposure.

It is a lot of work but if any salt water residue is left it will fester and so it is pay now in labour, or pay a lot later in parts.....

Viking also has a series of SB's covering water operation.

Salt Away
 

I use this product on my boat: It dissolves the salt and leaves metal/plastic squeaky clean:

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