Engine Pull

[F-16GUY]

Have some questions regarding engine pull and reinstalation on twin engine fighters. I would like to know the following from techs who have worked the actual types:

Regarding Eurofighter, F-18 Super Hornet, F-15 and Tornado.

1. How many crew members are normally involved in an engine change?
2. How long time will it normlly take for the above number of techs to change one engine?
3. How long time will it take to change both?
4. How long time does it take to perform an OPS check afterwards before the aircraft is released for flight.

Assumtions:
The engine change is done at a dedicated facility and all the required tools and spare parts are available.
I am not looking for an answer that tells me what the record is. I am looking for day to day realistic timelines.

Thanks in advance.

[Just This Once...]

Pretty quick for the Tornado when compared to the F-16. The forceps delivery technique required for the Viper can be a challenge. Dropping an engine through the big doors underneath the Tornado is a relative breeze for a couple of guys. The hyd system being totally separate from the engine also helps. The paperwork and ops checks afterwards burn the time. Double engine changes are very rare events and I have no experience of them.

[Lyneham Lad]

And the purpose for asking such questions is???

[F-16GUY]

Discussion on another forum where the pros and cons of one vs. two engines is being discussed.

Our techs will normally be 3-4 guys for the task and they (claim :-)) to be able to have it ready for flight in between 4-6 hours depending on crew experiance.

One more question: how often does one/both engine need to come out of the jet for phase inspection? Our viper requires that every 300 hours.

[F-16GUY]

JTO,

How much is pretty quick?

On the Viper the HYD system is mounted on the Aircraft gearbox and it is only connected to the engine via a simple PTO shaft (three bolts or so in each end).
Not an expert on the hardware part, but the way the engine is installed in the F-16 with the roller on top to hang it from the top of the fuselage seems as a smart and easy way to speed up the process.

Paperwork is not part of my question but OPS check is.

[Vendee]

On Tornado you really need 3 techs, 2 to operate the winches and 1 to keep an eye on things as the engine goes in or out. Actually, 4 was the norm with one guy up top.

Time to change the engine..... depends if you have a dressed engine to fit. My most recent Tornado experience was that the new engines never came dressed but back in the 80's and 90's, engines supplied from UK engine bay came dressed while RAFG engine bays supplied undressed.

With a dressed engine, you could change it in about 2 hours plus runs. Undressed engine was double that. Lots of dressing items to swap over, T/R buckets, finger seal carriers, NCU and TRCU exhausts, drains, HP air offtake etc.

[flipflopman RB199]

Can confirm Vendee's times for the Tornado.

During particularly busy periods or during detachments, it has not been unknown for a single Propulsion bod to complete an engine change within 5-6 hours, with minimal assistance from any other available people to help with the actual winching part! :ok:

Paperwork, Independents and Post Installation runs would all add another couple of hours to this before the jet would actually be signed off as fully serviceable.


Flipflopman

[glad rag]

Can confirm Vendee's times for the Tornado.

During particularly busy periods or during detachments, it has not been unknown for a single Propulsion bod to complete an engine change within 5-6 hours, with minimal assistance from any other available people to help with the actual winching part! :ok:

Paperwork, Independents and Post Installation runs would all add another couple of hours to this before the jet would actually be signed off as fully serviceable.


Flipflopman

So what about a double ECU change??

"particularly busy periods or during detachments, it has not been unknown for a single Propulsion bod"

Mugs abound!!

[LowObservable]

A couple of data points.

http://www.gripenblogs.com/Lists/Posts/Post.aspx?ID=295

Note from the photo that the engine can be raised and lowered by two hand-powered geared winches, which are also used to load weapons.

http://www.gripenblogs.com/AnalyticsReports/Johan%20Brolin-F%C3%B6rsvarsmakten.jpg

And here is the minimal equipment required to R&I an engine on (cough) a different fighter aircraft.

http://www.g21.com.au/sites/default/files/styles/img_half/public/field/image/marand_aerospace_image.jpg

[oldpax]

The trolley looks more expensive than the engine!!!!

[LowObservable]

It looks like lots of degrees of freedom to get that big fat thing in a deep tight hole. And with those small wheels and >4 tons of weight it's just as well they don't need to do it at an unimproved site. Wait, what?

[glad rag]

A couple of data points.

http://www.gripenblogs.com/Lists/Posts/Post.aspx?ID=295

Note from the photo that the engine can be raised and lowered by two hand-powered geared winches, which are also used to load weapons.

http://www.gripenblogs.com/AnalyticsReports/Johan%20Brolin-F%C3%B6rsvarsmakten.jpg





Love the rag [well I would] holding the flap up.


That's cab's built for the USMC that is....adapt, improvise, overcome and all that...



PS wonder how much they charge for a bag of F-35 rags? Don't even think about a toilet seat!!!

gr

[Madbob]

At the risk of thread drift as F16-GUY only asked about engine changes for the F16, F18 and Tornado but spare a thought for those doing an engine change on a Harrier. This involved complete removal of the complete mainplane, and because of the tandem u/c meant "propping-up" the fuselage so it didn't fall over!


All of this though could be done quite quickly ISTR and was even practiced in the field - and I really do mean in a field! It also had to be carried out at sea in the hangar when I imagine the ship's movement could make things quite tricky though I have no experience of that.


I have no idea of the manpower required or the time it took and for me it just happened and serviceability of the GR3/T4 fleet (I left the RAF in 1989) was always pretty high - 90% plus was normal then and near 100% when on an exercise/deployment.


MB

[Vendee]

I didn't spend long on gr3 sqn but remember that engine change took 2 shifts to complete. It was quite a PITA compared to Jaguar or Tornado eng change. Tiedown runs were exciting though.

[NutLoose]

I always thought the VC10 engine change broke all the rules in the book re Health and Safety, the bomb winches being the standard items were too short, so one winched the engine up with extension cables added to the winch cables until just below the bay, you then attached four cables onto the engine and lowered it back down until it was hanging on them, then you jumped down onto the hanging engine, detached the winches, removed the extensions cables, re-attached the winches, winched it up, removed the support cables and then proceeded to winch it home.

I seem to remember the Puma record for an engine change being well under an hour :)

[F-16GUY]

Thread drift yes, but interesting non the less. I can imagine how well concealed the engine of the harrier was, with its position midship plus all the plumming to the nozzels.

Still looking for info on the Tiffy, (Mud)Hen and Super Bug....

[NutLoose]

Jaguar was three on the winches as the engine was rolled slightly as it went in, one in charge / checking clearances etc and often one up top watching the fwd mounting, then a couple or three guys connecting it all up.

[LowObservable]

Some interesting info:

http://www.harrier.org.uk/history/engine_change.htm

From the designer's viewpoint, engine access for a fuselage-buried motor is a bit of a difficult trade. Structurally - there's by definition an engine-sized hole in the back end, so why not use that? Of course the connections can be a bit of a nightmare. The wrench-turners would love to have big access doors and hoist it into place, but that can be a pain with load-paths.

One advantage of a twin is that a lot of loads can be carried on a central keel that also supports the vertical stab. A twin canard or delta is even nicer because there are no H-tail loads.

I rather liked the F-5/T-38, where the aft fuselage and H-stabs come off completely to pull the engines. The neat bit is that the hydraulic actuator for the horizontal tail is forward of the break, with a simple mechanical linkage, so there are no lines to connect and reconnect.

http://www.adspast.com/store/skin1/images/pics7/northrop642f5engine.jpg

[NutLoose]

Super sabre was similar? Same with the L39.

[NutLoose]

They do a quick release engine BTW, here it is undergoing testing

https://www.youtube.com/watch?v=T4bn1WG5LS0

[LowObservable]

The whole back end came off the Sabres - which presumably meant messing with the plumbing.

[Vendee]

Jaguar was three on the winches as the engine was rolled slightly as it went in, one in charge / checking clearances etc and often one up top watching the fwd mounting, then a couple or three guys connecting it all up.Not forgetting to connect the No.2 engine inboard HT lead before rolling the engine into place. It was very difficult to connect it with the engine in place.

[F-16GUY]

I wonder how far it went? Looked to be in full quooker when it left the testbed...