Airbus family-BUMP??
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Join Date: Dec 2002
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Airbus family-BUMP??
Can any of you experienced guys tell me what is meant by 'BUMP' on the airbus? (I assume it doesn't mean that the aircraft has hit a runway designator sign!!)
Does it have something to do with the autothrust system? It seems to appear in the pre-takeoff checklist alongside the 'de-rate' call/response. Anyone who can shine a bit of light on this, please do so!!
Cheers.
Does it have something to do with the autothrust system? It seems to appear in the pre-takeoff checklist alongside the 'de-rate' call/response. Anyone who can shine a bit of light on this, please do so!!
Cheers.
Join Date: Mar 2000
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Bump thrust is an option available on the IAE V2500 series engines fitted to the A320 series which is selected by a little button on each thrust lever after engine start and adds something like 5% to TOGA thrust for getting out of places which normal TOGA will not allow. Trouble is that it plays havoc with engine life.
Doubtless those with more knowledge than me will fill you in on the technicalities.
Cheers,
mcdhu
Doubtless those with more knowledge than me will fill you in on the technicalities.
Cheers,
mcdhu
Join Date: May 2002
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Our A320s are equipped with this "Thrust Bump" function.
It is activated by 2 guarded pushbuttons located on the thrust levers and according to our manuals gives about 10% improvement in thrust.
But as mcdhu says, it is very detrimental for engine life and we only use it in the cases where takeoff using the normal engine rating would not be possible. And we make an entry in the tech log when we use it.
The improvement on the perfo MTOW is about 2 Tons with bump.
Hope this will help...
It is activated by 2 guarded pushbuttons located on the thrust levers and according to our manuals gives about 10% improvement in thrust.
But as mcdhu says, it is very detrimental for engine life and we only use it in the cases where takeoff using the normal engine rating would not be possible. And we make an entry in the tech log when we use it.
The improvement on the perfo MTOW is about 2 Tons with bump.
Hope this will help...
Join Date: Feb 2002
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Quite correct,
What it actually does is to duct cooling air around the turbine casing, thus reducing engine turbine tip clearances to a minimum and therefore blade tip losses (it works in conjunction with the active turbine clearance control system).
However because tip clearance is at a minimum there is the possibility of blade tip abrasion and higher EGT. Each BUMP is recorded in the tech log because after a certain number the function is no longer allowed to used unless the engine is overhauled.
What it actually does is to duct cooling air around the turbine casing, thus reducing engine turbine tip clearances to a minimum and therefore blade tip losses (it works in conjunction with the active turbine clearance control system).
However because tip clearance is at a minimum there is the possibility of blade tip abrasion and higher EGT. Each BUMP is recorded in the tech log because after a certain number the function is no longer allowed to used unless the engine is overhauled.
O\zon
