tarzanboy
Posts: 124
Joined: Fri Sep 12, 2003 8:18 am

Using Little Runway For Jet Landing?

Mon Dec 22, 2003 5:58 am

guys...

my hometown airport is 10000 feet long...

a new terminal building was recently built about midway of the runway,,,

i sometimes notice that on approach...jets (such as 737-800 and airbus a310), overfly the runway for a long period before gliding down for touchdown..

i came to a conclusion that the guys do this because they don't want to land to close to the beginning of the runway, in order to avoid a long taxi to the terminal...is this done on purpose?

i difinitely don't think that ground effect will be the case all the time...so i think it is purposely done....

i think this is a dangerous feat though....wat if for some reason you get ground while gliding her down past the middle of the runway???

hmmm......call the medics!!!!!!!!!!
 
rendezvous
Posts: 531
Joined: Sun May 20, 2001 9:14 pm

RE: Using Little Runway For Jet Landing?

Mon Dec 22, 2003 6:07 am

The chances of an unexpected encounter with the ground are no more present in this case than on any approach. In some ways I think it's safer to approach high (as long as you do have enough runway to stop on safely), because you get more clearence over obsticles.

As for the long landing, not too sure about the reason. I'm pretty sure you can stop the planes in 5,000' if you try? On the other hand, is there a displaced threshold?
 
OPNLguy
Posts: 11191
Joined: Tue Jun 15, 1999 11:29 am

RE: Using Little Runway For Jet Landing?

Mon Dec 22, 2003 6:19 am

>>>i came to a conclusion that the guys do this because they don't want to land to close to the beginning of the runway, in order to avoid a long taxi to the terminal...is this done on purpose?

Operationally, it would would make more sense to land normally, i.e. more towards the touchdown end of the runway, slow, and turn-off the runway at mid-fleld, assuming there is a taxiway at mid-field on which to do so.

If there no mid-field turn-off, and a landing aircraft has to go all the way to the far end of the runway before taxiing back to the terminal, landing way further on down the runway "wastes" runway that you might need to stop. (One of the three most useless things in aviation: the altitude above you, the runway behind you, and the fuel you just dumped). If the only taxiway off the runway is at the far end, it makes more sense to land normally, and keep the rollout moving towards the end once you're on the ground.

Some landings are "floaters"... Maybe you saw a couple of those...
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
Mr.BA
Posts: 3310
Joined: Sun Sep 24, 2000 12:26 pm

RE: Using Little Runway For Jet Landing?

Mon Dec 22, 2003 12:19 pm

On small propeller planes I've seen many pilots do this... they 'float' the plane quite far down the runway in order to vacate at their desired taxiway provided they have atc clearance to do so. Anyway they'd take a longer time if they touchdown normally and roll down the runway so ATC's normally fine with them doing that.

For big jets I believe pilots should always touchdown normally at the TDZ... I mean planes like those land at much higher speeds and they could brake lightly and roll down and they'll not stop as fast as the props do.
Boeing747 万岁!
 
tarzanboy
Posts: 124
Joined: Fri Sep 12, 2003 8:18 am

RE: Using Little Runway For Jet Landing?

Mon Dec 22, 2003 1:13 pm

rendexvous

no displaced threshold in the scenario i am talking about...
 
SlamClick
Posts: 9576
Joined: Sun Nov 23, 2003 7:09 am

RE: Using Little Runway For Jet Landing?

Tue Dec 23, 2003 2:42 am

Hard to tell without seeing your actual airport and maybe talking with the crews. Here in the US, with the major carriers, pilots MUST touch down within a certain bracket - for example, at the 1000' touchdown zone marker plus or minus 250 feet. To do otherwise may subject them to re-training or other consequences.

I'd go with the suggestion of normal touchdown and roll out with no real braking effort. Easier on the airplane.

You would not believe how short a jet airliner can land. I have landed a DC-9-15 (no leading edge slats) at a high elevation airport with a medium load in a 1700 foot ground roll, 2700' total from the approach end of the runway. The brakes did it all, the engines never even spooled up in reverse before we were below 80 knots and bringing it out of reverse. The brakes got hot, but not dangerously hot. I have seen a DC-10 flown by McD test pilots land shorter than that at KYUM. No reversers on that one.

Still, with passengers on board it is better by far to touch down on the aiming marker.


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