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Author Topic: Oil Temperature Control Doors  (Read 2763 times)

amchale

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Oil Temperature Control Doors
« on: December 10, 2021, 12:21:32 pm »
Hi all, novice question here, but how are the oil temperature control doors used during normal flight operation? Do they have to be shut off before takeoff/in flight and opened during taxi/after landing? Seems to be a pretty unique system as I have not seen another turboprop with pilot controlled oil doors. Is there operation OAT specific or a constant checklist item?

Bruce Byerly

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Re: Oil Temperature Control Doors
« Reply #1 on: December 10, 2021, 11:01:38 pm »
Simple answer: open on ground, closed before takeoff

donv

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Re: Oil Temperature Control Doors
« Reply #2 on: December 11, 2021, 11:09:24 am »
My only difference is that I close them immediately after raising the gear on takeoff. The AFM for the 980 specifies closing them after takeoff and opening them before landing. However, I open them right after landing... I don't think it makes much of a difference, and if I don't open them until I'm on the ground, I don't have to worry about them on a go-around.

Simple answer: open on ground, closed before takeoff

Bruce Byerly

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Re: Oil Temperature Control Doors
« Reply #3 on: December 11, 2021, 06:05:22 pm »
My only difference is that I close them immediately after raising the gear on takeoff. The AFM for the 980 specifies closing them after takeoff and opening them before landing. However, I open them right after landing... I don't think it makes much of a difference, and if I don't open them until I'm on the ground, I don't have to worry about them on a go-around.

Simple answer: open on ground, closed before takeoff

Don, of course that won’t hurt but why have more things to do after TO vs fewer? We’ve learned a lot since 1979, such as not doing overspeed gov checks as specified.  I submit the original POH is outdated.

donv

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Re: Oil Temperature Control Doors
« Reply #4 on: December 11, 2021, 06:47:02 pm »
That's probably a fair comment, although I have so much muscle memory doing it this way over the last 35 years that I'm not planning to change.

I do think it makes a difference if you are operating in really hot environments. In that case, I would follow the AFM procedure.

On the overspeed governor thing, that is due to an unfortunate typo that Twin Commander has never bothered to fix. Honeywell/Garrett never intended for that to be a first flight of the day check, but mistakenly someone way back in the mists of time at Rockwell inserted a comma where there wasn't supposed to be one.

The result is that "Check prior to the first of the day when inflight engine shutdowns and airstarts are to be accomplished, or any maintenance or adjustment has been performed" became "Check prior to the first flight of the day, when inflight engine shutdowns and airstarts are to be accomplished, or any maintenance or adjustment has been performed."

See what a difference a comma makes?
« Last Edit: December 11, 2021, 06:50:12 pm by donv »

seanmcgillivray

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Re: Oil Temperature Control Doors
« Reply #5 on: December 12, 2021, 10:01:07 am »
Mine are open prior to engine start and on then on the ground. When I line up on centerline for TO I do the following:

- Friction locks checked
- Condition levers high RPM
- Trim/flap indication check
- Oil door closed
- Prop sync confirmed off
- Ignition/ice as needed
- Stall/Pitot on

donv

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Re: Oil Temperature Control Doors
« Reply #6 on: December 12, 2021, 01:10:45 pm »
Sean, if you did an NTS check on start, you should also do the NTS check valve test. That is the last thing I do before rolling down the runway. Condition levers high, flip each NTS test switch to see no lights on the panel, and then go.

Personally, I do an NTS check on pretty much every start (habit pattern), so I do an NTS check valve test on pretty much every takeoff.

Also, depending on your airplane, in hot weather you may want to wait on the pitot heat until you are in the air. On my 980, the stall warning heat is powered off of the right pitot heat switch, so the AFM recommends (and I agree) in hot weather to not turn the right pitot heat on until airborne. I know later serial number 980s (and maybe all 1000s?) have a squat switch for the stall heat, so it's less of a big deal.

seanmcgillivray

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Re: Oil Temperature Control Doors
« Reply #7 on: December 13, 2021, 03:08:07 pm »
Newbie question Don.

Is the idea with the follow up NTS test to confirm once you operated the system the test circuit is functional?

My first day startup is :

TQ Limit Off
NTS Test On
Fuel On
Air Start
Confirm NTS Test Light
Feather Value Check
NTS Lock Check
Ground Start
NTS Light On and then Off and stays off

Thanks!

donv

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Re: Oil Temperature Control Doors
« Reply #8 on: December 13, 2021, 04:11:02 pm »
Sean-- that is correct for the NTS test itself. The "NTS Check Valve Functional Test" which I do on lineup (basically flipping each NTS Test switch to NTS and seeing that the corresponding light on the panel does not come on) is a validation that the NTS check valve is closed.

On my last recurrent with Barry Lane, we went through this in detail-- he even has the whole assembly, so you can see how it works directly. Unfortunately, my memory is only so-so and I can't explain it as well as he can.

Another Commander instructor, long ago, emphasized to me that if you do the NTS check on start, you need to do the check valve test as well. Barry agreed.

I do the NTS test on every start, because it's an easy habit pattern, and that way I do all my starts in the same way.

donv

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Re: Oil Temperature Control Doors
« Reply #9 on: December 13, 2021, 04:13:15 pm »
Specifically, here is the NTS Check Valve Functional Test from the 980 AFM:

Power Lever - FLIGHT IDLE
Condition Lever - HIGH RPM
TEMP/NTS sWitch - NTS. NT light illuminated; NTS TEST light, on center instrument panel, should not illuminate
TEMP/NTS Switch - NORM. NT light out.
Condition Lever - LOW RPM.

CAUTION
If either NTS TEST light illuminates, correct fault before flight.

So since you are lined up on the runway with the condition levers in high already, all you need to do is flip each switch and look for the corresponding light to NOT turn on.