Originally Posted by
Ranger
I'm not a Bus driver (thank God) so I can't speak specifically to that airplane. The tire speeds on the MD-11 are company imposed limitations. Neither the aircraft nor tire manufacturers impose the limits. Even at 10K for a 90 degree turn the inside nosewheel tire is off of the ground during the turn.
It's true that there is no stated restriction on the use of max autobrakes in the MD-11. But I think we'd pretty much all agree that you need a good reason to use max. The brake temps get pretty high after a max brake landing. And if I remember correctly, there's a required minimum 45 minute turn time after a max brake landing. Like we could turn one faster than that.
Isn't it the outside nosewheel tire that comes off the ground in sharp turns?
At touchdown, there is a certain amount of kinetic energy that must be converted to something else in order for the airplane to achieve taxi speed. A good deal of that is converted into heat in the brakes. Whether it takes 3 seconds, or 15, it is about the same. What I'm trying to say is MAX braking rate shouldn't make the brakes a whole lot hotter than MED or MIN. Yes, somewhat higher, but I don't know about "brake temps get pretty high" higher.
But the reversers... yeah, I know the reversers change a lot of that. If you have a long runway and get to use reversers down to 60 knots, and then start using wheel brakes, they'll absorb a lot less energy, and be lots cooler. Consider, however, that our landing distances are calculated using no reversers, and brake temps have to be within limits in that case, too. Basically, the cooler temperatures enjoyed by using MIN BRAKES are not because of the slower rate, directly. The cooler temps result from longer use of the reversers.
I don't recall a 45-minute cooling restriction after MAX BRAKING . . . but it's been a couple of years. Where did that come from? The APLC module requires cooling when certain environmental conditions and aircraft weights are combined, but I don't think it mentions AutoBrake setting. There's not even an INPUT for that parameter.
MINIMUM QUICK TURNAROUND TIME
When a specific combination of OAT, Pressure Altitiude,
Winds and Runway Slope is encountered
for a given runway, the aircraft is required to remain
in the blocks for a minimum turnaround time.
When these conditions are experienced, a "B" is
shown next to the affected runway and a note appears
in the lower portion of the screen stating "BReqd
Block Time (Min): xx”.
I might have missed it or forgotten it, so that's why I'm askin'. I'm not aware of such a restriction in the DC-10, and I
am supposed to know that stuff now.
BTW, I've seen a MAX BRAKING stop in the DC-10 (from the Oiler's Seat) in Subic... impressive.
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