PDA

View Full Version : stopping a DC9 quickly


lynn789
22nd Feb 2010, 22:58
I met a man who said he had been involved with developing the DC9 and that they couldnt meet a requirment for a fast stop after touchdown.
someone eventually said why not retract the undercarriage and let the plane slide to get extra braking

he said this was written into the flying manual, is this actually correct or just a fable?

Capt Claret
22nd Feb 2010, 23:21
Isn't the idea to be able to reuse the aeroplane after landing?

Lynn789, me thinks one of your legs is longer than t'other.

vapilot2004
23rd Feb 2010, 01:30
I could be wrong, but methinks braking tires produce more friction than sliding metal. Safer and better directional control too. Someone is pulling your leg.

and as the Captain states above, you get to use the airplane again. :ok:

Mad (Flt) Scientist
23rd Feb 2010, 01:41
The only circumstances I can think you'd even consider an intentional wheels-up landing on a runway is with a foreknowledge of complete and utter braking system failure, in which case your choice might be between sliding on the belly or rolling on unbraked wheels. Even then it would seem a dicey choice, given all the damage (and hazard) from the belly landing.

And even if that were the preferred option, you would be landing on the belly, not trying to retract the gear during the roll-out. (Apart from anything else, that kind of complete braking system loss probably means a loss of multiple hydraulics on most aircraft, which might make gear deployment and retraction more doubtful anyway).

It does all sound very unlikely.

catiamonkey
23rd Feb 2010, 02:24
One notable exception: the A342 and 343 can't land if one main gear is up and the center gear is down. You're supposed to retract the gear and do a belly landing. The risk of structural damage exceeds the risk of a belly landing.

Is there a similar case on any other plane?