S-92's Grounded
 

Just heard that all S-92's in Norway have been grounded.

Any news on the reason?

Checked on this - Word I heard was two aircraft found with chaffing hydraulic lines, rushing replacement parts from the factory as we speak.

Excuse me Nick, but what do you mean with "chaffing" ? weak or leaking?

Thanks.

Hydraulic lines flex as a result of the pressure pulses causing them to try to straighten out. The norm for any hydraulic line is to try to install it in such a way that it can flex without contacting other lines or surrounding structure. They have steel braids inside to take the pressure, so would only leak after high hours with plenty of warning that they are going to go.

I imagine this was just an oversight on the installation of these lines, which was spotted by the maintenance engineer. The grounding was most likely a precaution.

Mart

Graviman,

There could also be a wiring bundle routed with/over the lines and wires could be rubbing n the lines, or they could be rubbung against each other even. Or bad p-clipping, yes, I know they are new but that does not mean a thing.
It is scary how something as seemingly soft as an electric wire will work through a stainless steel hydraulic line in short order.

Grav and unstable have it right. The only reason they are on the ground is that the lines are factory parts, and not available locally (yet?) Once the chaffed spot gets to a certain depth, the tube is weakened enough to increase the possibility of a leak, so the tubes must be replaced.

I thought that was supposed to be fixed after the PHI fire. Perhaps only a few were modified. I would have thought the new ones coming off the line would have the mod, but perhaps not.

Gomer,
There are quite a few lines! I don't know where this one is, but you can bet it is not the same one as that on the PHI aircraft.

Nick

If this was a fixed wing carrying fare paying passengers would we have let the next line chafe?

I think the manufacturers need to up their game a bit when you consider the cost of these machines. A few teething snags is one thing but it is becoming a bit of joke when the operators are doing all the test flying.

Bit of a rant from a guy who has lost more than one mate this year....(not SK related)

cyclic,
I have been involved (on the fringes) in the arrival of a new type of aircraft and seen the snags and hassles that have been found. All new aircraft have a "settling down" time where the maintenance guys have a learning curve and the manufacturer depends on their feedback to improve their product as a consequence of this.
I have seen avionics do things that had the tech reps puzzled, wires chafed through on panels and the structure, pipes chafing and cracks appearing where they were not expected.

Those of you who have bought new cars or bikes should know about recalls and things breaking. Aircraft are no different, except that they get more column inches if things go wrong.
For what it's worth, the new aircraft were not Sikorsky, but that does not make them any different.

New is no excuse.

sox,

It was not presented as an excuse, rather as an observation of what happens when a new aircraft hits the road.

How else would you propose that the hours of flying and the input of the techs is gained?? Helicopters are already so expensive, now we should get the manufacturers to supply and fly them for free until they have all the bugs ironed out???
Similarly, GM should drive thousands of cars for years before they sell them.....:confused:

I am not looking to start a bunfight here, sox, rather I am trying to illustrate the difficulties faced by the manufacturers who build this equipment. Like Nick said, he does not know which pipes they were.

They could be in a completely different place because the operator in Norway is flying in different climatic conditions to the GOM and the stresses on the airframes would be different. Just like the 92's flying in Malaysia and Aberdeen will be different to the first one that goes to Australia.

Just how many 92's are in this fleet that had 2 grounded?

Can anyone name just one aircraft...fixed wing or helicopter....that did not have a learning curve and unforseen maintenance issues when first coming into service?

If anyone can recall the Chinook and the problems they had upon being fielded in substantial numbers in the '60's would laugh at the kinds of things the 92 has experienced. All these years later and the old girls are still around and going through their fourth or fifth rebirth as a higher Mk number....and some are being new built as well.

The Sikorsky S-61, S-64, CH-53 Family all spring to mind as well for being good machines after the initial problems were sorted out.

Why can we not expect the 92 to do the same?

Maybe there is not much to look forward to:
http://www.pprune.org/forums/showthread.php?t=254751

SAS,
well put, most eloquent.:D :D

Sums it up perfectly.

Happy new year to all out there and may 2007 be better and safer than all before.

Sasless

'Maintenance problem' - with pipes that are only available from the factory??

SASless,

Thanks for the wisdom! Please see that sox6 has one goal - keep this thread near the top, and keep selling 225's (on top of the 4 or 5 already sold, that is.....)

I actually posted some dirt on EC in a previous thread that he was pumping, but pulled it down because his game is not mine. He cannot see the ditchings and broken tail rotors on his favorite helos, but the chafing hydraulic lines on two 92's drives him nuts. So be it.

The 92 is a fine machine, and will probably be a classic. The Norsk fleet is now averaging 2,000 hours per S-92 per year. I don't know any old, proven machine that has shown within 3/4 of that flight rate!

Sox.....please don't try to convince me every operator in the world has every possible spare part for every machine all the time and never go AOG for something that must be shipped from the factory after the machine has been grounded!:=

I stood over an Agusta factory AOG coordinator once upon a time and watched him send a message to a customer telling him the factory planned to manufacture the part he needed....nine months down the road!

Nick

Are you paranoid? Amazing how you bring other manufacturers into every thread. Still so has SASless - brief summary "the S92 is like any other helicopter" but perhaps a bit better with spares that Agusta. How dissappointing for you. So much for those new certification rules and a Collier trophy. By the way: Where the 332L2s at Norsk not also doing 2000 hours per annum back in the late 90s? And 1500 hours is low time for any North Sea machine these days. Have a look at the oil price.

I fly 76s by the way. But I never believe the hype.

SASless

Suggest 'production' more likely than 'maintenance'.
From what I here ther are a lot of spares shortages on the 92. Though of course they could be down to the operator's spares forecasting too.

2000 Hrs per year is going some! I know first hand how hard it is to capture every fault expected in the service life of a vehicle. Assuming the design process is not a million miles away from this:

Concept-->Prototype-->Development-->Prod_development-->Production

A realistic aim is to capture >90% of this type of issue at each phase after concept, this still leaves perhaps 1 part in 1000 that will require modification during production. I have not seen the BOM for this heli, but there will have been more than 1000 new parts on a project like S-92.

Mart