Re: Hot Wheels

Date:         21 Nov 99 23:56:44 
From:         stevec01e@aol.com (STeveC01e)
Organization: AOL http://www.aol.com
References:   1
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>> . . . if a plane at near maximum
>> weight had to taxi for a long distance on a hot day, they might have
>> to wait for the tires to cool before takeoff in case they had to
>> abort the takeoff

Quite true. But it is to allow the BRAKES to cool, not the tires.  They have to
wait to cool off the brakes after any landing or heavy taxi(taxiing is usually
not a problem for brake temp--brake wear, yes).  This is important in quick
turn-arounds or a/c that fly short hops, as island jumpers such as JAL or in
Hawaii.

>I believe there is a max temp limit on the brakes for retraction after
>takeoff.  Also, brake performance drops as temp goes up.

   I'm not sure if the Flight Manual has crew check brake/tire temp before
retraction.  Gear retraction is automatic--in sense, crew has no time to ponder
the issue.  Most large a/c have provisions for cooling tires in wheel well and
heat detectors in case one does ignite.
    Hot brakes will effect braking performance.  So, a wait before takeoff is
good planning for a possible RTO(Rejected Take-off).

Steve Cole