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Feathering check


mrjpc130h
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Again... Hello freends n senior members..

I got doubt in my head since couple of month ago we got argument on feathering cx. In the technical manual stated that feathing cx must be not more than 23 seconds. We got an engine changed recently and d time is 30 sec. Our technician been change components to tht engin n still persist n as an operator we rejected tht engine coz in our opinion 23 sec is for prop feather n stop but d tech guys insist tht tht engine is ok n the time is only for prop to feather only not stoping. So please anybody knows any good opinion with good refernces so i cn get thru to clear ths argument?

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If asking about maximum time limit during in-flight shut-down, Functional Check Flight Manual stated the following: RPM will decrease to zero within 10 seconds and when propeller reaches full feathered position override button should pop out. And under “CAUTION†book stated the following:

If the propeller feather override button dose not pop out within 5 seconds after completion of feather cycle, pull out manually to shout off pump.

Put I believe you are asking about Propeller Static Feather Limit.

Our “Flight Manual†stated that during static feather check the maximum time for blade angle travel from reverse to feather or from feather to reverse is 23 seconds.

In our FM 382-6-CF (Functional Check Flight Manual) during static check and after positioning the propeller blade angle to maximum reverse; book states the following:

Pull the fire emergency control handle.

... The propeller should move from reverse to feather in 23 seconds or less.

Then under “CAUTION†book stated the following:

If the propeller feather override button dose not pop out within 5 seconds after completion of feather cycle, pull it out manually to shout off the pump. Maintenance action is required prior to flight.

Based on that I understand the following:

1-The time travel from reverse to full feather (feathering latch engaged with no farther movement) should not be more than 23 seconds.(excluding the time for the override button to pop out)

2-Feather override button should pop out within 5 seconds after completion of feather cycle.

Therefore to my understanding, the maximum full time limit from full reverses to popping out the button may extend to a maximum of 28 seconds.

Regarding your case if the time to full feather is within 23 seconds then your first part of propeller feathering system is good, the second part which includes terminated of the feathering cycle which should not exceed 5 seconds started from stopping movement of prop, if found to be more than 5 seconds, investigation should be done (blocked filters, malfunction pressure cut-out switch within pump housing, miss-adjustment of 86 switch, feather override relay, aux feather pump.... etc).

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TENTEN, I got the impression that the prop was spinning and on the ground when they were timing the feather shutdown, not sure why they were timing it this way but its not really something covered in the 6CF or any other tech manual. Like I said above they are really checking two different systems, the prop brake and the prop control assy.

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Yup agree... The feathering check for 23 seconds is for on ground feathering cx. The matter arises from exceeding up to 30 sec , when we did d FUnctional Check Flight the engine is was windmilling during cruise engine shutdown takes time to stop after feathered. Then d consequense tht engine unable to airstart normally n luckily with help from d starter to manage to light off the engine

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Wow, if I am getting you right you say it takes thirty seconds to feather on a ground check? Bad Prop assy (somewhere in there that is)

If its windmilling at all and then you have to use the starter to unpop the prop brake then I would look really hard at that prop brake being bad.

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Yup agree... The feathering check for 23 seconds is for on ground feathering cx. The matter arises from exceeding up to 30 sec , when we did d FUnctional Check Flight the engine is was windmilling during cruise engine shutdown takes time to stop after feathered. Then d consequense tht engine unable to airstart normally n luckily with help from d starter to manage to light off the engine

Maybe some engine guys could jump in here, but it sounds like a prop brake issue?? Is the prop counter rotating? During the last sentence there it sounds like the brake was engaged as you were trying to Air Start the engine, yes/no? If it was engaged bumping the starter makes sense. As for the feather time being 30 seconds, I see what tenten is saying about the feather override button and pulling it after 5 seconds. I'm also wandering if maybe you have a bad aux feather motor or low output? Just some thoughts, but there are mx guru's on here with more nuggets than myself!

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Yup agree... The feathering check for 23 seconds is for on ground feathering cx. The matter arises from exceeding up to 30 sec , when we did d FUnctional Check Flight the engine is was windmilling during cruise engine shutdown takes time to stop after feathered. Then d consequense tht engine unable to airstart normally n luckily with help from d starter to manage to light off the engine

What direction is the propeller windmilling after in-flight shutdown, and what is your airspeed when you shut the engine down?

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Issue much clear; Hope changing the prop will fix it....; anyhow for the sake of knowledge, the windmilling during flight can be one of the two:

1-Propeller failed to reach the full feathered angle (92.5°) within the proper time (10 seconds ref.6CF) thus prop keeps windmilling on the same direction of rotation (clockwise)

2-Propeller reached the full feathered angle, stopped/paused, then windmill on the opposite direction of normal rotation (anticlockwise).

1- For the first case to till what might be the cause more details is required ; anyhow it can be related to cable miss-rigging, valve housing miss adjustment, or components malfunction such as weak aux feather pump motor due to electrical or mechanical malfunction, internal dome leak(quad seal), or other malfunction within the valve housing. I never experienced this during any FCFs, or emergency shutdowns, most of the time it reaches full feather position within 6 seconds or less. And I believe the 30 seconds to stop is abnormal and should be corrected, the time factor of securing an engine if malfunction arise after refusal speed with an obstacle is very critical.

2- The second case is a well known case, caused by malfunction of propeller brake.

I did experienced this malfunction from time to time; prop will continue windmilling anticlockwise, and may stop if air speed is reduced. This malfunction in some cases can be fixed by proper flushing of brake.

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Dan..., tell you the truth, so far I am not sure what brother mrjpc130h is looking or asking for... Is it for time limit approval (30 seconds) from a good reference for a case defect taking place during flight..? Or is it about; what may cause the prop to take that unusual time?

If the last was the case, I am asking; what about ground static feather check? Is the prop passed the check limit (not more than 23 seconds from full reveres to full feather)??; ... And... Is the feather angle during ground check visually checked for 92.5 degrees?? ...What about engine coast-down time during ground normal shutdown? What components had been changed so far.........

It makes sense to pass the entire related ground check first; then to go for FCF.

Might be done, might be not, but never been told....; so, me and you Dan trying fishing on a dry river..!

Dan, prop brake is a possible defect, but the prop-if passed the 90 deg-then it should rotate counterclockwise, which was not the case as stated on the last post...!! let go.. Just one more throw on that river.

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Dan..., tell you the truth, so far I am not sure what brother mrjpc130h is looking or asking for... Is it for time limit approval (30 seconds) from a good reference for a case defect taking place during flight..? Or is it about; what may cause the prop to take that unusual time?

If the last was the case, I am asking; what about ground static feather check? Is the prop passed the check limit (not more than 23 seconds from full reveres to full feather)??; ... And... Is the feather angle during ground check visually checked for 92.5 degrees?? ...What about engine coast-down time during ground normal shutdown? What components had been changed so far.........

It makes sense to pass the entire related ground check first; then to go for FCF.

Might be done, might be not, but never been told....; so, me and you Dan trying fishing on a dry river..!

Dan, prop brake is a possible defect, but the prop-if passed the 90 deg-then it should rotate counterclockwise, which was not the case as stated on the last post...!! let go.. Just one more throw on that river.

Tenten...do you use a different manual because I'm used to a max reverse to full feather in no more than 25 seconds?? Just curious.

Dave

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Yes Dave, you might be correct, the 25 second I did read it somewhere, might be in USAF manuals, not on hand at the moment, I am having one as a reference, I will check it.

We are using Lockheed Manuals FM 382C-14E and FM 382-6CF for military registered airplanes.

And OM 382G-65C in conjunction with AFM 382/E/G for civil registered airplanes. (Lockheed Manuals FAA approved) And both manuals are stating the 23 seconds.

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Yes Dave, you might be correct, the 25 second I did read it somewhere, might be in USAF manuals, not on hand at the moment, I am having one as a reference, I will check it.

We are using Lockheed Manuals FM 382C-14E and FM 382-6CF for military registered airplanes.

And OM 382G-65C in conjunction with AFM 382/E/G for civil registered airplanes. (Lockheed Manuals FAA approved) And both manuals are stating the 23 seconds.

Both the 1C-130H-1 and the 1C-130H-2-61JG-10-1 have 25 seconds listed as the limit from reverse to feather position. This is for propeller static operation testing only, not for engine operation. Typically though, the engine emergency shutdown is about 10 seconds to full feather and button popout due to having the main and standby pumps increasing the blade angle along with the aux, so there has to be a lot wrong for the engine to take 30 seconds to go static or reach full feather in flight.

I am also suspecting that the propeller blades are not reaching full feather position, which would easily explain the 30 second engine static time in flight only, with a post-shutdown rotation clockwise when viewed from the rear, but it is not exactly clear what the exact defect is in the posts, so I can't recommend one thing or another. I do see that the engine was already changed, and the prop is being changed right now. Engine rigging cannot be the cause as the feathering action is both electrical and mechanical, so everything else is either already eliminated or about to be. The discrepancy is hard to understand, but from what I CAN understand, I'm guessing the feather blade angle is too low.

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