Originally Posted by
johnso29
We do not, but a limitation was just recently changed and I think it is to line up with the DAL Mad Dog procedures.
If the runway is NOT contaminated we can deploy them before the nosewheel touches down, but have to wait for the nosewheel to touch in order to spool them.
If the runway IS contaminated we must wait until the nosewheel is down before we can deploy them.
My guess is it has to do with how the clamshells can hinder the aerodynamic effectiveness of the rudder. I don't know if DAL has the same limitation as AA on their Mad Dogs, as they are much longer then even a DC-9-50.
I was snooping around dlnet and read that memo about T/R deployment on the 88 and I believe there was something in there about the lower clamshell potentially striking the ground if it was deployed right away with a higher than normal deck angle on touchdown.