BAe LIMIT THE 146 TO FL260 DUE ENGINE ICING.
 

In the daily telegraph this morning, small article saying that older generation 146's are being limited to 26000' after an aircraft's engines 'iced up' on a recent Marseille-Stansted flight.

Anyone know anymore about this? Guess this would be a BUZZ flight?

Seems strange, as on the 737 you can turn the engine anti-ice OFF in the climb/cruise above about 26000, as the SAT drops below
-40 and icing can no longer form.

I jumpseated on a 146 recently and there was a clear placard stating that '26000ft altitude limit applies in icing conditions'.

However we were not in icing conditions and were at FL310.

Does this rule now mean that all 146 operations have to be at 260 and below no matter what the conditions are?

I am sure some 146 drivers will keep us right! :)

MG

------------------
Don't land in a field or the sheep will eat the aircraft.

Pretty sure it was Buzz 146-300 G-UKAC engine #4 - read it somewhere recently. One of the older ones around I believe.

See http://www.open.gov.uk/aaib/apr01htm/gukac.htm

I spoke to pilots who select engine anti-ice off where-ever possible as it saps too much power from the already under-powered engines.

(they also turn all cabin lights off for departure ;) )

[This message has been edited by GJB (edited 16 April 2001).]

The 146 has been limited to FL260 in icing for sometime, if we go higher and encounter icing we have to descend. Since the routes we fly are never that far, it doesn't hinder the flight too much. It does slow the climb when we have all the anti ice on, this gives extra time to eat those lovely crew meals!

Nope, sorry, you're all wrong! :)

The ONLY 146 aircraft that are limited to FL260 or below in icing conditions, are those that DO NOT have the engine mod that prevents rollback in icing conditions. If your aircraft has three or more modded engines, the aircraft can go above FL260 in icing conditons.

Many companies choose to impose the limit in a blanket fashion, in the belief that pilots, renowned for their stupidity, might inadvertently go above FL260 in an aircraft with less than the requisite number of modded engines... ;) However the MANUFACTURERS limit is as stated above.

In my company, most engines are now modded. We can breathe easily again!!

Oh, by the way, this is VERY, VERY OLD news!!!!

[Edited for typo]

[This message has been edited by Raw Data (edited 16 April 2001).]

As far as dimming the cabin lights for take off is concerned, whilst I realise that this will no doubt improve power somewhat, is this not simply a (UK?) regulation that operators of all a/c types adhere to for safety reasons?

RAW DATA of course you are right. Unfortunately in my company we don't have the mod and can't see us getting it.

Hey RD http://www.pprune.org/ubb/NonCGI/frown.gifor anyone else)
Could you please ellaborate on "modded" engines?

cheers

DT

What is 'rollback', why does it happen?

TECH...AGAIN I've always been told that the reason cabin lights are dimmed for take off (and landing) is so that if an evacuation were to be necessary and the lights were to fail, then the pax eyesight would already have adjusted to the ambient light conditions outside the aircraft. However, I've only ever been told that this needs doing "during the hours of darkness".

hey faq:
"The term ‘Rollback’ is used to describe a particular uncommanded thrust reduction on the Lycoming ALF-502R engine. It manifests itself as a slow reduction in the high pressure spool speed (N1) associated with an increasing Turbine Gas Temperature (TGT) and a failure of the engine to respond to the pilot thrust lever. Following considerable research and analysis complemented by flight tests conducted by the airframe and engine manufacturers, the cause of roll-back was determined to be due to the build up of ice on the engine core super charger exit guide vanes in very specific meteorological conditions. The build up of ice on the guide vanes progressively ‘chokes’ the engine core. A modification (30437A) was devised to improve the anti-icing efficiency and is in the process of fleet embodiment. In the interim, following a study of the pattern of roll-back occurrences, an operational limitation was introduced for aircraft with unmodified ALF 502R engines by the issue of a Temporary Revision to the Aircraft Flight Manual (AFM)."

make any sense!?!?!?

:) :) :)

146LUKE- as far as I know, the mod is mandatory, so yes you WILL be getting it! Lycoming mode every engine that goes through their workshops, apparently. The final compliance date isn't too far away either...

Methinks Raw Data is totally correct in what he says here -- it is indeed very old news and I seem to recall it was first imposed back in the early nineties due to a four engine flameout on an Ansett Western Australia 146 that very nearly ploughed in. I think the crew managed to get just two relit at extremely low altitude.

I'm somewhat surprised to see it posted here as 'news or rumour' some 10 years later. Is it possible that some operators of the type are not aware of this problem? Surely not.

BAe are very up front about the rollback problem and even issued a jepp sized page to remind you about it if you could miss all the plackards in the aircraft and fell asleep for most of the training.
To quote raw data "very very old news"

Raw Data, unfortunately our contract ends fairly soon!

DCG,

That's just what I thought - cheers for the post.

TA

Interesting. As I said, I'm just posting what was reported in the 'Daily Telegraph' yesterday, so I don't know where they got that from.

Raw Data, or other 146 drivers :
Do you turn the engine anti-ice off below a certain temperature (-40 SAT in the 737)? This equates to 27500 ft. in ISA conditions.

Of course, the Telegraph hates BAe because they support Europe and the big 'satan' that is Airbus (which they fail to realise supports thousands of UK jobs), so could be part of their 'campaign'.

Not necessarily LUKE737 - well not according to big Stu!!!!!!!!