View Full Version : V2500 cooling period
Flex33
2nd Jul 2004, 11:15
Has your companies V2500 cooling period recently changed from 3 minutes to 5? Do you know why?
It may have something to do with the significant number of engine failures we've experienced in the past 12 months!
Always been 5 mins over here.
The V2500's suffer from rotor bow. The cause of which has been determined to be uneven cooling within the engine. Hence it is vital to ensure that the engine has thermally equalised before shutdown. My guess is that your company ops were different and it has now become a costly short cut.
That said, in my opinion the main reason for the rotor bow problem is crew spooling up the engines to get the a/c that last few yards up the ramp and then just shutting down instead of allowing 5 mins cool down. Heard it many times and always gave the pilot a b*****king when I saw him.:\
Spearing Britney
3rd Jul 2004, 16:28
5 mins warm up and 3 mins cool down is our SOP and was in my last lot too...
Our FCOM states 3 min cool down after operation above normal taxi power (40%N1) so if it it needs 40% to park it gets it and then gets shut straight down. Any eng who has a problem with that has a problem with my SOP's not me and I would tell him so!
Pretty sure RR advice has always been 3 mins cooldown until it was upped recently when the V2500's with the latest mod (Increased compressor blade tip clearance) also started to experience failures.
I remember a few Derby based people who were always highly sceptical of the rotor-bow phenomenon.
foxtrot
4th Jul 2004, 17:07
hi guys
Airbus recommendation is 3 min after deselection of max reverse and thereafter engines operated at idle power for thermal eqalisation but some airlines recommend 5 mins even after usage of idle reverse that is to minimise the potential for oil cooking in the main engine bearing compartment.
makes sense
bye.