JAS grounds planes

[rotornut]

Cracks in US engine parts ground 120 flights in Japan
19.01.2004 [21:00]


Japan Air System said it had cancelled 120 domestic flights affecting 7,000 passengers on Monday after discovering cracks in US-made engine parts from at least seven McDonnell Douglas aircraft.
JAS, a subsidiary of Asia's top carrier Japan Airlines System (JAL Group), reported engine trouble on January 6 and 7 in an MD-81 and an MD-87 jet and asked US engine manufacturer Pratt and Whitney to check the engine parts.
Engineers from the US company discovered cracks in engine compressors from the two aircraft and JAS then conducted its own investigation on engine parts used in six other McDonnell Douglas jets and found the same type of cracks in engine parts from three MD-87s and two MD-81s planes.
The MD-87 plane has a capacity of 134 passengers while the MD-81 airplane can carry 163 passengers.
The discovery of cracks in at least seven planes prompted JAS to investigate the other 19 MD jets in its fleet, 14 MD-81s and five MD-87s, resulting in the cancellation of 120 domestic flights on Monday alone.
"It is regrettable that the move will affect some 7,000 passengers. At this moment, we cannot tell when the inspection of the 19 aircraft will end," said JAS spokesman Hirohide Ishikawa.
On January 1, two passengers were slightly injured after the left wing of a JAS airplane carrying 168 people clipped a runway in southwestern Japan.

AFP, Jan 19

[Rosbif]

Are thes the same engines as in Jetsgo's 'planes? If they are, this could get veeeery interesting:ooh:

[lomapaseo]

Kind of hard to relate a wing scrape and a cracked engine part together. But what the heck

[BeachBum]

According to Japanese press, this incident involving JAS MD-81 and MD-87 engines has nothing to do with the main gear collapse incident JAS MD-81 experienced on January 1. As the previous post indicates JAS has experience two engine incidents this month involving MD-81 and MD-87. According to Japanese press JAS operates both MD-81 and MD-87 using Pratt & Whitney JT8D-217A/C engine. JAS has decided to check all of its MD-81 and MD-87 engines after these two incidents. Currently JAS operates 18 MD-81 and 8 MD-87. The engine incident involved compressor of the engine, specifically the stator fin, the stationary blade in the compressor. Both incident involved 8th stator blades from the front of the compressor.

As of evening of January 20, JAS has completed the examination of 24 MD-81/MD-87 aircraft they have. Out of that JAS has found the crack in the stator blade in 17 aircrafts, 19 engines. The mechanics told that cracks found on the stator blade was large enough that they could identify by naked eye. They did not have to use magnifying scope or ultrasound. JAS has only two spare JT8D-217A/C engines ready for immediate installment. JAS has to get more spare parts from Pratt & Whitney to complete replacement of all of problem engines they found. JAS is scheduled to cancel 62 flights on January 21. JAS is planning to minimize the cancellation by utilizing JAL aircraft.

I would expect European and the US authorities both will issue the immediate inspection of compressor stator blades of JT8D-217A/C engines, which is commonly installed in MD-80 aircrafts series. But I have not heard any cancellation of MD-80 flights in the US, have you? It is hard to believe that this engine problem is unique to JAS MD-80s.

[Ignition Override]

We will undoubtedly see, uh..., immediate action by the (US) FAA.......uh....yeah...like...for sure, dudes. Maybe they were sweating the results of the cost/benefit analysis today in Wash. D.C.

Remember the (unrelated) problem with some ATR-42s in Europe and how nothing was done by the FAA-aware of some very serious aileron problems in icing conditions-until much later after the horrible tragedy at Roselawn, IN?:rolleyes:

[DocManhattan]

lomapaseo - As BeachBum said, Jan. 1 incident wasn't just a wing scrape, it was a landing gear collapse that injured (at the latest count) three pax, at least two of whom were taken to hospital. Subsequent inspection on the rest of the fleet revealed cracks in the main gear of one other aircraft. The bird with the broken leg is ``not written off - yet'' JAS said yesterday, but given that they're no longer counting it in the fleet numbers they're giving the press now, you've got to suspect it's in a pretty bad way.
This problem may well be totally unrelated to the engine cracks, but you've got to ask yourself how come this is all happening at once, and only to JAS? SAS said yesterday it has no intention of grounding its fleet of MDs ...
JAS now saying it wants to lease JT8s from Pratt to replace the damaged engines, though they don't think there'll be enough available to get the whole fleet operational again any time soon.
Will be interesting to see if any similar problems turn up in anyone else's MD fleet, or is something wrong with the way JAS maintains these aeroplanes?

[rotornut]

Associated Press
Japan Air System Planes Still Grounded
Wednesday January 21, 10:34 am ET
By Natalie Obiko Pearson, Associated Press Writer
16 Japan Air System Planes Remain Out of Service With Engine Cracks; More Flights Canceled


TOKYO (AP) -- Sixteen Japan Air System planes remained out of service Wednesday due to cracks in their engines and the carrier announced more flight cancellations after completing emergency inspections.

The Federal Aviation Administration, meanwhile, said Wednesday that "preliminary" information gathered from U.S. carriers and Pratt & Whitney, the manufacturer of the jet engines, indicates that the problem is isolated to the JAS fleet.

JAS has grounded more than 200 flights since beginning inspections Monday on all 25 of its MD-81 and MD-87 aircraft. The review was prompted by two cases of engine trouble earlier this month.

With two-thirds of those planes still grounded, 59 flights would be canceled Thursday, affecting some 4,400 passengers. Nine planes would be in service, including two that had had faulty engines replaced, the airline said in a statement.

The engines were produced by Pratt & Whitney, the East Hartford, Conn.-based builder of jet engines for commercial and military aircraft.

The cause of the engine cracks still had not been determined, but JAS was asking the U.S. company to investigate the problem as it conducted repairs, said JAS spokesman Tomonari Sato. Earlier, JAS had cited a possible design flaw as the cause.

FAA spokesman Les Dorr said the agency is working closely with Japan's civial aviation authorities, Pratt & Whitney and U.S. carriers that fly MD-80s, such as American Airlines, Alaska Airlines and Delta Air Lines.

"The preliminary information indicates that this is limited to the JAS fleet and is not typical of worldwide experience," Dorr said.

"If we need to take some safety action, whatever that might be, we would not hesitate," he added.

A Pratt & Whitney spokesman said its engineers have been dispatched to Japan and are also working on the problem at the company's Connecticut headquarters.

"We are working with JAS to understand what the problem they seem to have is and get their fleet back in operation," Pratt spokesman Mark Sullivan said Wednesday. "We've seen these kinds of problems periodically in the past."

On Jan. 6, an MD-81 had to abort its takeoff at Fukuoka airport in southern Japan due to vibrations in an engine. A MD-87 returned to Kagoshima airport, in southern Japan, the next day after developing a similar problem.

Inspections of the two planes turned up cracks in a compressor in their engines. Subsequent checks on all JAS aircraft of the same type turned up additional cracks and, in some cases, missing blades. Officials had said cracks or missing blades in the compressor can cause a plane's engine to vibrate, lose power, or even stop.

Officials at U.S. carriers told The Seattle Times they had experienced similar problems previously in the same type of engines in their fleets but that they were not aware of any at present.

American Airlines discovered five similar cracks on MD-80 engines in the past nine years. It does not consider them a major concern, but had requested more information, the newspaper quoted spokesman John Hotard as saying.

"We are still awaiting word from Pratt & Whitney on exactly what JAS has experienced," Hotard reportedly said. "We need to know more about these cracks and exactly where these cracks are located."

The affected aircraft were produced by McDonnell Douglas, which merged with Boeing Co. in 1997. JAS uses the aircraft only for domestic flights.

JAS and Japan Airlines set up a holding company, Japan Airlines System Corp., in October, 2002, and were to merge their flight operations in April this year.

[visibility3miles]

Sorry, I started a new thread on this topic before I realized this one was here:

http://www.pprune.org/forums/showthread.php?s=&threadid=116223

http://www.cnn.com/2004/WORLD/asiapcf/01/20/japan.jet.engines/index.html

[747FOCAL]

So much for that MD-80 Hushkit that causes the engine to rotate over redline. :uhoh:

[willbav8r]

Anyone else ever so slightly worried at P&W's wishy washy response?? And as for the FAA,.....nuff said.

How is it with so many engines having stator vane problems that it doesn't warrant immediate checks worldwide?

[BeachBum]

Update on JAS MD-81/MD-87. Ministry of Land, Infrastructure and Transport of Japan has announced that JAS has completed the inspection of all 52 Pratt & Whitney JT8D-217A/C engines, including spares, as of January 21. 21 engines were found to have a crack on a stator blade in a compressor. 31 engines were found to have no damage on a stator blade. Five MD-81 and two MD-87 were found to have both engines without a stator blade damage. Addition to that JAS has fitted two MD-81 with a spare engine they had. Total of nine JAS MD-81/MD-87 are airworthy at this time, according to Ministry of Land, Infrastructure and Transport.

JAS is working to get leased JT8D-217A/C engines. Where only one engine was found to have a crack in a stator blade, JAS is removing a good engine from one aircraft and trying to match with another aircraft with only one good engine. JAS will cancel 59 flights on January 22, and JAS has said that it will take least few weeks to have all MD-81/MD-87 back to airworthy and return to normal schedule.

I have one question. Is no.1 engine and no. 2 engine on MD-80s interchangeable? I mean, can a left engine on one MD-80 aircraft be used as a right engine on another MD-80 aircraft? Is correct that all four engines on 747 are inter-changeable? JAS has said that they are putting one good engine from one aircraft to another aircraft. I am wondering if no. 1 engine from one aircraft have to be used as no. 1 engine on another aircraft. Just curious.

[HotDog]

All engines are totally interchangeable from left to right or vice versa.

[747FOCAL]

Actually Hotdog I think they rotate in oposite directions for assymetry........:E

[BeachBum]

Follow-up:

JAS has announced that leasing of Pratt & Whitney JT8D-217A/C engines are going better than expected. JAS is planning to return all of its MD-81 and MD-87 back to service by February 7, and return to normal schedule on February 8. In all JAS will cancel total of 596 flights due to MD-81/MD-87 engine problem, and estimated loss due to this incident to be JYE 500 million (US$ 4.7 million).

The engine manufacture Pratt & Whitney said that they have not heard or seen any similar incidents of JT8D-217A/C from any other users. This obviously suggests the possibility of specific maintenance or operation procedure by JAS as a cause. However, at this moment JAS has been following the procedure which was approved by both the manufacture and the government agency (Ministry of Land, Infrastructure and Transport, which oversees commercial aviation in Japan).

[DocManhattan]

Getting a slightly different take on things from the JAS side ... The full schedule will be restored by Feb. 8, but that doesn't mean the MD-80 fleet is going to be fully repaired by then. They're going to pull in other aircraft types to operate the services they can't fly with MD's, and as far as I know they're still sticking to their earlier schedule of getting the MDs fixed by the end of February. Not sure why Pratt would say otherwise.
JAS contact tells me Pratt does all their JT8 overhauls, but you've got to ask yourself why nobody else seems to be having this trouble, while JAS has found the problem on 75% of its fleet.
And those landing gear cracks on two of the aircraft? That's just too much of a coincidence on one fleet in one month.
Don't think I'll be rushing to fly with those guys for a while ...

[faq]

Didn't the landing gear collapse after landing on a British registered MD80 in the mid 90's at MAN?

[Rosbif]

Wasn't there an uncontained blow up on an MD 80-something about ten years ago. Killed the pax sitting in the wrong place ??

[Ranger One]

Rosbif:

This is the one you're thinking of, I think:

http://www.ntsb.gov/Publictn/1998/AAR9801.htm

Delta at Pensacola, 1996. Two pax killed, two seriously injured.

Cheers

R1

[Anti Skid On]

FAQ

An Airtours MD83 collapsed one of it's main gear some time in the nineties (can't find the report). More recently this (http://www.caa.co.uk/docs/33/FACTOR200338.PDF) happened to a Spanair MD83 at Liverpool.

[Few Cloudy]

Thread's got off track. This may bring it back.

Why only JAS? Why only MD-80 series? Why in January? Why on an otherwise remarkably reliable engine?

OK. No speculation - some background facts:

The MD-80 has long been known to have severe cold soaking of the upper wing root surface in the area of the centre tank -which extends into the roots. Also in the inboard area above the wing tanks, where the fuel gathers due to dihedral. This happens especially after long flights, where the remaining fuel gets undercoooled.

At temperatures up to 10 deg C (it has even happened to me at 14 deg C in drizzle in Tunis) in any appreciable moisture - even mist, very clear ice forms on the affected surface and cannot be detected without a hands on check. If not removed, the ice remains snugly in place and cracks off as the wings bear the weight on lift off - only to be blown straight into the waiting intakes a few metres further back. It can happen to your Fokker 100 too.

This was the cause of the famous SAS accident in Stockholm and has caused many other documented occurences of engine damage.

For this reason, MDC offered or approved various packages including:

- a fuel recirc system, which forces warmer fuel from ground tanking to flow by the wing root area.
- an ice detector on a piezo basis to warn of tank top area icing.
- various tassels and flags on the wing upper surface to make ice easier to identify.

NON of these methods guarrantees there to be no ice in the critical area. The only way is the hands on check - via a ladder - a vehicle or (which no-one likes because of the possibility of wrong re-fitting) through the emergency exit window.

Some companies rigidly enforce this hands on check up to six degrees - some to 10 degrees and some to 15 degrees. Some do not.

So far no speculation - just facts.

Now let's take a look at Japan - a very long country running from sub tropical Okinawa (as far as MD-80 ops are concerned) up to Hokkaido in the north, where the houses are all double glazed.

The shortest leg on the network is about 20 minutes - the longest over 2 hours - time enough for the phenomenon mentioned above to occur.

MDC and Pratt once issued a bulletin about the "soft ice phenomenon", where even non-brittle ice and slush entering the compressor causes nicks, scratches and eventually cracks.

Still not speculating - it seems to me that:

a) Grounding the fleet is a tremendous over-reaction on such a well tried and well known airframe / engine combination

b) The American colleagues are correct to handle this as an separate - maybe airline related case.

Yes I have flown there. Yes on MD-80 and seen how seriously or otherwise the ice problem has been taken. Yes it may have some completely different cause.

By the way using max reverse when idle would suffice and never using reduced thrust on Takeoff doesn't shorten engine life either.

Just background.

FC.

[lomapaseo]

Few Cloudy

I fail to see any linkage with your mixed facts and postulations.

The SAS certainly was not a cold soaked fuel problem since it was the first flight of the day following freezing precip overnight.

I can see no linkage between your soft/ice/slush SB and nicks and scractches in a compressor.

As I understand the JAS situation it was not a fleet wide grounding involving non-suspect aircraft but only limited to aircraft that had a specfic mainetnance history (parts and SBs).

[Few Cloudy]

Hello lomapaseo,

If the whole fleet hasn't been "grounded" - the word used in the title to this thread - that is a good thing.

The linkage you say that you can't understand isn't mine. The technical cause and effect of compressor damage - catastrophic or ongoing on PW engines at the back end of MD-80 series aircraft - including the "soft ice" problem, is documented in MDC and PW bulletins over the past years.

You maybe right about the cause of the ice on the SAS machine not being cold soak related. Nevertheless, deicing in the morning failed to shift the surface layer of ice and it is well possible that it formed as a result of cold soak (I don't know where the flight originated the evening before) and was subsequently disguised by later ppn.

It doesn't matter why the ice formed, of course - main thing is to make sure it is off the wing before TO. Fuel tank surface ice is the classic - well illustrated in a Finnair photo of a huge thick cake of ice being removed from an MD-80 after it had been on the ground for several hours and moved into a hangar if memory serves right.

Overnight icing can clearly be due to many causes including the freezing PPN you refer to on the night in question. Winter ops does occur in FUK on occasion. It is not dealt with as efficiently there, as in the north, where it regularly occurs. But I don't want to speculate - same thing happens when you get snow in Rome, compared to Copenhagen.

Other FOD ingestion is also a blade damager. The engines are right behind the mainwheels on the MD-80 and experience in one European airline shows that regular flights to poorly maintained runways or taxyways often show up in blade nicking. The field in question was Tirana in Albania a while back but it has also showed up at "good" airfields where work was in progress and debris not properly cleared, as well as Scandinavian fields where runway surface ice has cracked loose. The cautious use of reverse (not above idle unless needed) also reduces the static circulation effect at lower speeds - a known cause of MD-80 FOD ingestion. It is why the reverse buckets were "canted" in the evolution from the DC-9 series.

It's just background info. however. Let us see what the boffins find out...

[BeachBum]

Update

Ministry of Land, Infrastructure and Transport of Japan has made an announcement regarding JAS MD-81/87 engine incident. The announcement indicated that only those engines which received a maintenance repair on stator fins showed cracks on stator fins.

Stator fins are welded onto a metal plate in a compressor. However, on JT8D-217A/C engines it is possible to develop a gap between a metal plate and a stator fin after about four years of use. The manual written by Pratt & Whitney indicates that a stator fin parts to be replaced with a new one or repaired after certain time interval. JAS contracts this specific stator fin maintenance to a subsidiary company of Pratt & Whitney in Singapore.

The investigation so far showed that only those engines which received a stator fin maintenance at Singapore showed cracks on a stator fin.