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-   -   How Long??? (https://www.pprune.org/military-aviation/616925-how-long.html)

NutLoose 4th Jan 2019 16:57

How Long???
 
Innovation In Tight Spaces


The current guidelines used for aircraft maintenance required that the entire engine be removed, which would require at least 36 hours per jet.

but does reveal the surprising fact that it takes “at least 36 hours” to remove an F-35A engine – and presumably another 36 hours to replace it.
It would take longer to fit BTW.


Coltrin went on to say that their partnership is strong because many of the functions that existed within a traditional maintenance squadron with fourth generation aircraft now lie within the fifth-generation aircraft maintenance squadron.

More now than ever we rely on each other to accomplish organic maintenance. On fifth-gen aircraft it takes a village. No squadron can go it alone,” said Coltrin.

organic maintenance.
How apt, no artificial fertiliser, just natural pure sh*te :E
LOL 36 Hours.



..

unmanned_droid 4th Jan 2019 18:02

I guess they aren't supposed to break...

Fareastdriver 4th Jan 2019 18:07

Is that supposed to mean 36 'man hours'. Should that be so its six blokes in six hours.

Rigga 4th Jan 2019 19:02

Typical assumption of man-hours over elapsed time. Even with 6 people it is more reasonable to assume 10-15 hours elapsed time.

NutLoose 4th Jan 2019 19:41

I don't think it is man hours because in the article it says


Maintainers working with field support engineers from Lockheed Martin and Pratt and Whitney set out to find a way to replace the fuel line without removing the engine.

Crew chiefs determined they could access the part through a hole just big enough to fit a hand. The location of the fuel line is nearly impossible to see. They needed to detach and set aside another component without removing it, making room even scarcer.
When the OTI was first accomplished, the fuel line swap took about 24 hours, 12 hours less than removing the entire engine and performing the maintenance on a stand. As they repeated the task on additional aircraft,


so if you only have a single hand access and that takes 24 hours, but 36 man hours works out less when you spread them across the team, then you would pull the engine as it's a quicker fix. I suppose the thing is the jumping bean version with the front lift fan etc.

Always a Sapper 5th Jan 2019 15:32

Why not just make the access hole bigger, or are we then getting into material stress territory?

SASless 5th Jan 2019 16:28

Recruit some skinny wimmen!

Problem sorted.

Lyneham Lad 5th Jan 2019 16:58

Ah yes, man-hours. I recall the WO on Aircraft Repair Flt 390 MU many years ago stating to SEngO regarding a small repair estimated at forty man-hours, that if he had forty men he would have done in an hour...

And now back to your regular programme.

Cows getting bigger 5th Jan 2019 16:59

Last VSTOL aircraft I saw on the RAF inventory could have the whole job done in a few hours, in a hide, in a boggy field, having removed the wings to get to it. :)

Pontius Navigator 5th Jan 2019 17:26

It isn't the first aircraft with impractical access. Wasn't it a Victor or Herc where a fitter got his arm in but couldn't get it out? IIRC they had to open up the wing.

Vendee 5th Jan 2019 17:28


Originally Posted by Always a Sapper (Post 10352691)
Why not just make the access hole bigger, or are we then getting into material stress territory?

You will probably find that the access hole is actually there to service a different component but is being used (at a stretch) to get access to this particular fuel line. Panels tend to add weight and reduce strength so the designers have to strike a balance between the needs of the maintainers and the structural requirements of the airframe. Usually the maintainers lose out.

unmanned_droid 5th Jan 2019 17:45


Originally Posted by Vendee (Post 10352775)
You will probably find that the access hole is actually there to service a different component but is being used (at a stretch) to get access to this particular fuel line. Panels tend to add weight and reduce strength so the designers have to strike a balance between the needs of the maintainers and the structural requirements of the airframe. Usually the maintainers lose out.

Sorry - we will always push for fewer holes in our structures! Every one has a stress impact and thus a weight impact.

Bksmithca 5th Jan 2019 18:14


Originally Posted by NutLoose (Post 10351880)
Innovation In Tight Spaces





It would take longer to fit BTW.





How apt, no artificial fertiliser, just natural pure sh*te :E
LOL 36 Hours.



..

https://cimg8.ibsrv.net/gimg/pprune....0fb706d09f.jpg
NutLoose
Given what I saw at the Smithsonian last summer I would say 36 hours to remove this engine is being generous.

BK

Fareastdriver 5th Jan 2019 20:15


Last VSTOL aircraft I saw on the RAF inventory could have the whole job done in a few hours, in a hide, in a boggy field, having removed the wings to get to it. https://www.pprune.org/images/smilies/smile.gif
Did a field trial where we used a Puma to lift the wing off when it was in the middle of the sticks. A sod of a job putting it back on.


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