VASI
Topic Author
Posts: 187
Joined: Thu Aug 17, 2000 3:33 am

PW 4000 Series

Fri May 04, 2001 4:28 am

Hello!

As I read many articles about the PW 4000 engine I heard that it suffers sometimes from problems in the high pressure turbine. To my knowledge P&W was working on it very hard, but with little success, the modification package proved to be a failure.
So my question is: What exactly is the cause of the failure and what can be done to prevent this? How can you recognize such a failure as a pilot?

Perhaps you remember the famous photo of a MD-11 taking off in Zurich with flames bursting out of one of the engines.

Thank you very much!!!!!!

VASI
 
FLY DC JETS
Posts: 191
Joined: Sat Feb 26, 2000 1:13 pm

RE: PW 4000 Series

Fri May 04, 2001 7:57 am

You may have read a significant number of articles, however, it should be noted that the PW has reliabilty figures that compare with the CF6 and both have numbers that are significantly better than the Rb211 that competes.
 
Guest

RE: PW 4000 Series

Fri May 04, 2001 9:20 am

The problem with that SR MD-11 taking off with flames coming from one of it's P&W 4460 engines was from engine surge. At least with the P&W 4000 series engines the fan blades do not come apart like they have been doing recently on the GE CF6 series.
 
MD-11 forever
Posts: 550
Joined: Wed Mar 14, 2001 12:15 am

RE: PW 4000 Series

Sun May 06, 2001 10:38 pm

Well, the PW4000 (especially the 94" Fan model) has some big surge problems. To make things worse, recently there wasn't a result after extensive investigations. I heard now that P&W formed a task-force to investigate the trouble and find a solution for it, after all the previous attempts failed (with high financial damage for some overhaul shops and airlines). The trouble is mainly that the HPC has a high load on every stage, that means the engine operates closer to the surge margin than another one with some additional stages. So I think they will have a difficult job to improve the engine......

Cheers, Tom
 
VASI
Topic Author
Posts: 187
Joined: Thu Aug 17, 2000 3:33 am

MD-11 Forever

Mon May 07, 2001 3:02 am

Thanks for the answer!

Is PW paying for this damage too?

As I fly really often on the SR MD-11's I'm interested on how to detect such a surge.

Do you hear it as a passenger?

What is the normal procedure in case of an engine surge? Just shut it down and return?

Thanks a lot !!!!
VASI
 
JT-8D
Posts: 423
Joined: Sun Dec 31, 2000 11:34 pm

RE: PW 4000 Series

Mon May 07, 2001 6:05 am

P+W better reliability than rb-211? I dont think so.. I also have not heard of any persistant probs with P+W 4000 series. We operate ge-90, now there is a hunk of junk..
 
FLY DC JETS
Posts: 191
Joined: Sat Feb 26, 2000 1:13 pm

RE: PW 4000 Series

Wed May 09, 2001 6:04 am

I am referring to the RB211 version offered on the 747. The engine has suffered from numerous durability problems. Hence the H/T upgrade that is being offered to operators of the type. The PW4000 and CF6 do have better numbers with regard to statistics on this airframe. If I recall correctly, however, i could always be wrong.
 
JT-8D
Posts: 423
Joined: Sun Dec 31, 2000 11:34 pm

RE: PW 4000 Series

Wed May 09, 2001 6:14 am

As my experiance runs only to 757, I will concede this point. I have heard of probs with the -22 models, on the L-1011. All I can say is that we never open the cowl of our 757s. They just dont break. We put oil in them, thats it. We had nothing but problems on our cf-6-50 engines. vbv, vsv, bleed probs(not really engine related). I didnt like the rb-211 when I first came in contact with it. Why 3 spools? Why so many external oil and pneu lines? But after a while, I didnt care. If it aint broke, dont fix it. And ours just dont break..
 
FDXmech
Posts: 3219
Joined: Sun Mar 19, 2000 9:48 pm

RE: PW 4000 Series

Wed May 09, 2001 11:53 am

I'll agree that the RB211-524's that I've previously worked at AA were virtually troublefree.

On the other hand the CF6-50 is also extremely reliable, the only problem I've encountered with the VSV/VBV system being the feedback cables needing replacement due to binding. Usually this causing higher than normal EGT or other parameters to trend south. But their have been cases of CF6 stalling at high power due to *misrigged* VSV cables (with associated engine R&R).

The Pratt 4000 is a great engine but I don't like it near as much as the CF6-80.
First off is Pratts philosophy to use cowl load sharing to compensate for their insistance at using fewer bearings to support their rotating assemblies. Their cowl latching system turned a routine engine button up (GE) into a chore, especially on #2 engine on the MD11.
When I was told that to clear certain FADEC faults on the Pratt EEC you need to actually open the engine and remove one of the data plugs I was stunned (my first thought was #2). This is done on the CF6-80 inside the cockpit.
Durability wise the JT9 was superior to the CF6-6/50. I guess it had to be as stalling a JT9 was more prevelant than the CF6 (a very rare occurance). Yet now the point is moot as *both* Pratt and GE have very tight tolerances (the old Pratt addage, "damage can cause a stall but a stall won't cause damage", no longer applies).

Tedski,
Which CF6-80 engines have had their fan blades come apart? Is Pratt immune?

JT-8D
As a mechanic I respect your opinion. Some I agree and some not. If all mechanics agreed all the time, the breakroom would be a very boring place.
You're only as good as your last departure.
 
JT-8D
Posts: 423
Joined: Sun Dec 31, 2000 11:34 pm

RE: PW 4000 Series

Wed May 09, 2001 12:02 pm

fdxmech, you are correct. Cant agree with everyone. Im in a battle with a group of people now that think a 707 should be flown inverted. Long story. Im not looking for any more arguments tonight. I never had probs with the JT-9, lots of non engine probs with the cf-6( thrust rev, bleed, eng a/i that sorta stuff). Just remember changing lots of sensors on the cf-6 also.
 
Guest

FDXmech

Fri May 11, 2001 5:25 am

It was recently on a US Airways CF6-80 powered 767-200ER that was undergoing an engine test on the ground when all of a sudden the engine came apart. What about the incidents involving those two Continental CF6-50 powered DC-10s at EWR and KLM 747 taking off from LAX and parts of the engine fell on a nearby beach?

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