Originally Posted by
llanfairpg
Lots of rubbish above!
There is a potential for dirt/crap and even debris to be thrown from the wheels on lift off which can go into the bay and rupture hydraulic lines or worse in the case where a tyre seperates so best to stop then spinning straight away, thats why they are braked, if you dont understand this say CONCORDE several times and you will!.
Yes there is isn't there?
Most a/c I know only brake the wheels when gear selected up. They will spin away quite happily until hydraulic fluid is ported through the landing gear selector valve to the brakes.
As has been mentioned, the A320 MEL allows for a u/s brake, and SOPs state that the gear is left down for 2 mins after t/o to allow the wheel to spin down. (Gyroscopic forces and all that malarky apparently).
