goboeing
Posts: 2429
Joined: Mon Jun 05, 2000 5:31 am

Gear Down Timing

Sat Aug 09, 2003 3:54 am

This caption got my curiosity:


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Photo © Art Brett


"Inbound to 13L, less than 2 miles from touchdown, surprisingly the landing gear has not yet been lowered."

What would a reason be to wait this long to extend the landing gear in a jet? Less than 2 miles from touchdown on a normal glideslope would mean this plane is at about 500-600 feet AGL. I remember reading either in this forum or somewhere else that usually, airlines typically require the plane to be fully configured for landing at 1500' AGL in IMC, and 1000' AGL in VMC. Could it be that perhaps the pilots simply...forgot?! Maybe it was caught during the checklist or a warning sounded with the last flap extension?

Landing on 13L at JFK involves a right hand turn after Canarsie VOR, and the turn is rather late on the approach, not quite Kai Tak but it's still 1500' or less.

Nick
 
cancidas
Posts: 3985
Joined: Thu Jul 03, 2003 7:34 am

RE: Gear Down Timing

Sat Aug 09, 2003 3:58 am

i dont think he's at only a couple hudred feet. maybe 1000agl, depending on the glideslope. he may also be coming in quick, or he forgot. i hope he didnt forget! he would still have enough time after the turn over CRI to drop the gear.
"...cannot the kingdom of salvation take me home."
 
goboeing
Posts: 2429
Joined: Mon Jun 05, 2000 5:31 am

RE: Gear Down Timing

Sat Aug 09, 2003 4:21 am

A 3 degree glideslope at 2NM is 636' AGL. CRI must be crossed at or above 1500', yes, but it still seems late to put the gear down.

People who fly jets: when is the typical point when you extend the landing gear? If you're on a visual approach in the middle of the night with no other traffic? If your cramped in the approach sequence with planes in front and behind? If it's going to be an autoland or an ILS to minimums?

Nick
 
LHR340
Posts: 819
Joined: Tue Apr 29, 2003 1:18 am

RE: Gear Down Timing

Sat Aug 09, 2003 5:15 am

I think they normally put the gear down at 12 miles.


LHR340
A340 LoVeR! EC-GQK - LHR The Bussiest International Airport & 3rd Bussiest In The World!
 
m717
Posts: 540
Joined: Tue Dec 31, 2002 1:01 pm

RE: Gear Down Timing

Sat Aug 09, 2003 5:30 am

12 miles out is a bit far from the airport to normally be extending the landing gear. In answer to Nick's questions:

Middle of the night, visual approach, no traffic--maybe 3 miles out.

Cramped in the approach sequence with traffic in front and behind--depends on ATC instructions. If they don't give you any specific speed instructions, where you need to "slow to final approach speed" or anything like that, then around 5 miles, or G/S intercept. If you get the "slow to minimum approach speed" (which happens occasionally here in ATL when they have them packed in on final, and you're following a 757 a bit too closely  Smile ), then at that point to reduce to your final approach speed.

Autoland or ILS to minimums--just prior to G/S intercept. (If you're doing it "by the book".)
 
dash8tech
Posts: 708
Joined: Mon Jul 05, 1999 8:40 pm

RE: Gear Down Timing

Sat Aug 09, 2003 5:39 am

Maybe he's already made a "go around" decision at this point. Flaps don't appear to be set too far down either for landing.

GPWS will warn you with a "too low gear" aural alert if you're descending below (if memory serves me) 500' and less than 200 knots.
 
PilotHighFlyer
Posts: 217
Joined: Wed Jul 23, 2003 8:48 am

RE: Gear Down Timing

Sat Aug 09, 2003 7:40 am

Maybe the aircraft is farther out than reported by the spotter and the pilot is trying to accommodate ATC by making a faster than normal approach.

Robert
 
buckfifty
Posts: 1278
Joined: Tue Oct 16, 2001 4:05 pm

RE: Gear Down Timing

Sat Aug 09, 2003 12:05 pm

Maybe the aircraft is farther out than reported by the spotter and the pilot is trying to accommodate ATC by making a faster than normal approach

The first part I can agree with, the second part is awfully iffy. You can always put your gear down early to slow the plane down for sequencing, but not leave the gear up till short finals. It's a safety issue then (and the SOP's won't allow it), not a pilotage one.

The go around theory sounds okay, though. But then the photographer must have heard the engine sounds spool up for that.
 
CX Flyboy
Posts: 6030
Joined: Sun Dec 26, 1999 6:10 pm

RE: Gear Down Timing

Sat Aug 09, 2003 12:05 pm

In my airline, and on my fleet we are required to have full landing configuration and landing speed by 1500ft agl. If not, then it is a mandatory go-around.

Everyone does it slightly differently, but the norm is to have Flaps 1 at around 18miles to touchdown. Flaps 5 at 15miles. Joining the ILS at flaps 5, the aircraft may accelerate from the flaps 5 speed in it is heavy, especially a 777-300. In this case, we lower Flaps 15. If the speed holds, then at around 2400ft, I ask for "Gear down, Flaps 20" At around 1900ft I ask for Flaps 30. On days where the speed is a little slow to come back I might go to Flaps25 first, which has a slightly higer limit speed before going to Flaps 30. We always land at Flaps 30.

So to answer your question, we normally lower the gear at 8miles or so, at around 2300-2500ft. If the aircraft is having trouble slowing up, we may drop the gear a little earlier.

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