View Full Version : Airbus family-BUMP??
jonnys
4th Dec 2002, 12:58
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.
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
Using Rsv fuel
4th Dec 2002, 18:55
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...
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.
jonnys
6th Dec 2002, 12:34
Thanks a lot to all you guys who took the time to answer my question-I appreciate your answers.
Cheers.
Denver Bump?
pls explain.....
O\z
Captain104
13th Dec 2002, 09:58
Does it help to note the elevation of DEN?
(5431 ft./ 1655.4m)
Have a nice day. :)