PT6 compressor wash

[Bluemeaway]

hello

caravan 675shp 114A

trying to find

P&WC Special Instruction 4-84 relating to compressor wash

currently waiting for engine to cool to ITT 65 or 40mins whichever occurs last just trying to confirm that the company wash proceadures are in regards to 4-84

also does anyone have any methods for accelerating the cool down process (ie fan in intake)

cheers,

blue

[john_tullamarine]

External blowers prove to be very useful in cooling down the PT6 installation pre-CT wash.

[flying-spike]

I have seen one of my colleagues do a running rinse on a Porter, slowly pouring water from a bucket over the mesh screen. All was well until he slipped on the ladder and dumped the lot over the screen and put the fire out! ITTs came down rather rapidly after that. Can't say the same for the pilot's temperature though.

[ebby1028]

I think you will find the answer is it needs to be at ambient temperature!!!! That's what P&W said when I asked them directly. So go home, have a um..non alcoholic beverage and go back later. :)

[goin'flyin]

We used to use the rule that you had to be able to keep your hand on the side of the casing before you could do the water wash. If it was too hot to keep your hand on the case, it was too hot to wash.

Many an hour was wasted in summer standing around an airport at 8-9pm waiting for the engine to cool enough to wash.

[Grogmonster]

Bottom line is that you have to be a LAME or have a CASA Maintenance Authirity to do the Wash in which case you wouldnt have to ask as you would be armed with the appropriate knowledge. Sorry to be so blunt but that is an expensive and very necessary bit of equipment that is required for safe flight so dont touch unless you are competent.

Groggy

[ebby1028]

Correct:ok:

[VH-XXX]

Bottom line is that you have to be a LAME or have a CASA Maintenance Authority to do the Wash

If a CASA Maintenance Authority can be given to a standard line pilot non-mechanic, then yes.

[hurlingham]

VH XXX - They can be, and are given to non mechanic, line pilots

[VH-XXX]

Yep, I knew that, I just thought the comment was a little unclear indicating that a pilot could NOT do it. Didn't wanna put in my foot in case it had changed.

[MakeItHappenCaptain]

If it ain't listed in Schedule 8, then it shouldn't be done without AME/LAME quals.

The application will now be replied to with a letter stating CASA will not issue an AME approval to the candidate, however a dispensation has been issued to the effect of blah blah blah and is most likely to be effective for the next two years and only while the candidate is employed by the company making the application. Sure someone can put their letter's wording in. :ok:

(Mine's "international" atm.)

[fencehopper]

Best practise is for it to be done before commencment of days ops, did this years ago when working on line but now i watch pilot do it each morning in C208 and Cresco depending on what's online here.

[john_tullamarine]

Pratt guidance is for the CT rinse to be done at the end of the day's flying to get rid of the contaminants and reduce sulphidation etc.

Some/most folks do it the following morning to avoid either having to wait for the installation to cool down or pull out the blowers to force cool so that the boys can get to the pub a bit earlier.

I am aware of one large PT6 operator which has done this for some years without any adverse findings at O/H.

[zac21]

I think there is some confusion between a comressor rinse and a compressor turbine rinse.
A compressor rinse is only that, and is usually a hose connected to the intake ring.
A CT rinse involes removing the igniter and placing a tool in there to rinse the CT as well as the intake.

The problem with CASA is the removal and replacement of the igniter.

[Defenestrator]

Refer Refer AD/PT6A/28.

http://www.casa.gov.au/scripts/nc.dll?WCMS:OLDASSET::svPath=/ADFiles/turbine/pt6a/,svFileName=PT6A-028.pdf

We try and cool ours for 90 mins prior to washing. Pointing it into wind helps. Other than that not aware of any methods to expedite the cooling process.

The maintenance manual on a PT6-114A calls for the engine to be brought up to 80% Ng for 1 minute to dry it. Exercise the heater as well as it often collects small amounts of water that will eventually lead to corrosion. Particularly important following a performance wash.

Drying run not really necessary if the aircraft is going flying following the wash.

D.