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ATC Watcher
18th Jan 2010, 06:05
Probably already discussed here in the past, but can anyone with knowledge know if bad maintenance or bogus spare parts can cause/contribute to a compressor stall in a modern Jet engine ?

Ryanjames170
18th Jan 2010, 06:14
its very posibly could make it happen ie on bogus parts as for bad maintance yes but probably not right away just like with any machine..
if parts are left long past there due change date i am sure it could possibly cause one or much worse...

Keith.Williams.
18th Jan 2010, 11:05
Bad maintenance could cause malfunction of the VIGV /Anti-Stall bleed valve operating and control systems or in the FADEC. Bogus parts in these systems could do the same. Bad maintenance could also result in excessively dirty or worn compressor blades.

Bogus compressor blades could have incorect aerofoil profiles.


Any of these could cause compressor stall.

ATC Watcher
18th Jan 2010, 19:29
many thankss to both of you, very helpful.
And before you ask, no I am not intending to buy or sell bogus parts, just trying to understand a recent incident.
Tks again.

Ryanjames170
18th Jan 2010, 20:19
No problem

Shytehawk
18th Jan 2010, 20:37
Ryanjames

I get the impression that you know about as much about aircraft engineering as my cat.

smudgethecat
18th Jan 2010, 20:45
I think your being a bit harsh on your cat there shytehawk

lomapaseo
18th Jan 2010, 20:52
I get the impression that you know about as much about aircraft engineering as my cat.

I didn't interpret this as an engineering question. Like many questions on the board you really never know how to answer them correctly without a lot more background. However it looks to me like the answer was good enough to satisfy the original poster

Ryanjames170
18th Jan 2010, 21:21
yah i do know enough about it its just putting it into words with out knowing what he knows is the problem.. that and i am better at talking things out then writing them..
i actualy read a thing about compressor stalls like a day before i saw this post.

N1 Vibes
25th Jan 2010, 01:59
Sh!tehawk,

something I was told on my 1st day as an apprentice:

"In this business, there is no such thing as a stupid question."

Everybody has to learn somehow - share the knowledge, it might save your life or 400 other peoples lives one day.....

Best Regards,

N1 Vibes

draughtsman99
25th Jan 2010, 05:08
something I was told on my 1st day as an apprentice:

"In this business, there is no such thing as a stupid question."and for added information - "but there are a lot of stupid people who may give stupid answers!"

muduckace
25th Jan 2010, 11:55
but can anyone with knowledge know if bad maintenance or bogus spare parts can cause/contribute to a compressor stall in a modern Jet engine


Any machine can fail as a result of bad maintenance or bogus spare parts, happens all the time with automobiles and dish washers.

For years now (15-20) the more respectable federal aviation authorities have conducted programs to catch parts that are (bogus) or not overhauled from making it back into the system by mandating that airlines controll parts by maintaining lists of serial numbers and purchase order records for audit.

As far as the bad maintenance goes... Well you get what you pay for.

George Cortdery
25th Jan 2010, 15:40
I worked on the RB 199 , in the Design Office, at Filton with Rolls Royce Ltd.

Position: Senior Design Engineer & Section Leader. I worked under Trevor Laseter, our Group Leader.

It was not uncommon for new aircraft to suffer from Compressor Stall. This rules out Bogus parts theory.

The only factor that I am aware of, is the rate of change of R.P.M. of the spool.

Once up-and-running, at constant R.P.M., a compressor will never stall.

The Engine computer will control rate-of-change of RPM, within prescribed limits.

It is a sticky subject which can only be solved with an Ejector seat, on the Tornado.

However, the end result is always the same. i.e. Brown underpants.

muduckace
25th Jan 2010, 16:30
Once up-and-running, at constant R.P.M., a compressor will never stall

You post limited knowledge pertaining only to engines that do not rely on VSV's for compressor MGT. I like the rolls bleed system, just that there are alot of other motors out there and I am also sure that (if it can happen it will)

It was not uncommon for new aircraft to suffer from Compressor Stall. This rules out Bogus parts theory.


Don't like the word "bogus", but substandard or failed are more common and easier for me to swollow, once again I revert back to the VSV engines, that damb cable on CF6's through the -50. If it was sticky on throttle advancement...BANG. Could theoreticly fail at power and Big BANG. Does not rule out anything.

AviationGlossary
25th Jan 2010, 17:12
The following is from an article I posted on AviationGlossary.com
Typical Causes of Compressor Stalls


Excessive fuel flow caused by abrupt engine acceleration when the axial velocity (speed) is reduced by increased pressure in the combustion chamber due to the added combustion and the resultant rotational speed increase
Operation of the engine outside of its RPM design parameters affecting the rotational speed of the compressor blade
Turbulent or distorted / disrupted airflow to the engine inlet reducing the axial velocity
Damage to either the compressor or turbine blades
Low fuel flow due to abrupt engine deceleration causing a decreased back pressureCompressor Stall Flight Deck Indications


An increase in the vibration level of the engine
An increase in the Exhaust Gas Temperature -- EGT
RPM Fluctuations