dl767captain
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Why Keep The Gear Down So Long?

Thu Dec 20, 2007 6:41 am

I was watching a video on first flights and test flights and i noticed that they keep the landing gear down for the entire flight sometimes, and the other times don't retract the gear until a high altitude. So why do they do this?
 
2H4
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RE: Why Keep The Gear Down So Long?

Thu Dec 20, 2007 6:43 am

If you're on a test flight, relying on unproven equipment, why fiddle with nonessential equipment before you're able to shake down the essential stuff?

2H4
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georgebush
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RE: Why Keep The Gear Down So Long?

Thu Dec 20, 2007 6:48 am

Yea it would suck to be on a test flight, retract the gear, and then not be able to get it back down. Especially when your being filmed by 50 cameras, not good publicity.
Al Gore invented global warming.
 
KiloMikePapa
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RE: Why Keep The Gear Down So Long?

Thu Dec 20, 2007 8:04 am



Quote:
If you're on a test flight, relying on unproven equipment, why fiddle with nonessential equipment before you're able to shake down the essential stuff?

The gear is pretty essential ... for getting that expensive prototype and the possibly even more expensive test pilot back in a state allowing additional test flights Big grin!
 
jhooper
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RE: Why Keep The Gear Down So Long?

Thu Dec 20, 2007 8:26 am

On everyday flights, occasionally the gear is left down for an extended period for brake cooling.
Last year 1,944 New Yorkers saw something and said something.
 
dl767captain
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RE: Why Keep The Gear Down So Long?

Thu Dec 20, 2007 8:16 pm



Quoting 2H4 (Reply 1):
If you're on a test flight, relying on unproven equipment, why fiddle with nonessential equipment before you're able to shake down the essential stuff?

Ya but a lot of times they eventually retract it, but they are at a very high altitude
 
2H4
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RE: Why Keep The Gear Down So Long?

Thu Dec 20, 2007 8:35 pm



Quoting KiloMikePapa (Reply 3):
The gear is pretty essential ... for getting that expensive prototype and the possibly even more expensive test pilot back in a state allowing additional test flights

Yeah, I could have worded that better. I was thinking about how it's not so essential to retract the gear, considering the airplane can fly with the gear down. Best to leave it down until the systems essential for flight are shaken down and proven.

2H4
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HAWK21M
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RE: Why Keep The Gear Down So Long?

Fri Dec 21, 2007 7:46 am

Certain Tests could be carried out warranting the Gear down for the same as per the Checklist.
Observations after being recorded,The Crew proceed to the next test on the Checklist.

regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
Mir
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RE: Why Keep The Gear Down So Long?

Fri Dec 21, 2007 9:41 am

On a test flight, a lot of the equipment is unproven, so they only want to mess with it in a controlled setting with time to troubleshoot if things should go wrong - at altitude. Just in case something bad did happen on the takeoff and they needed to come around for landing, it wouldn't be ideal to have the first extension of the gear be one where they really needed it down, and needed it down quickly.

-Mir
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upsmd11
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RE: Why Keep The Gear Down So Long?

Thu Sep 04, 2008 8:40 pm

I was on a flight today (CR7 out of MDT) and the gear seemed to stay down until we were at about 10,000 ft at least, maybe a bit lower.

We had a normal take off, no rejection. We had a long slow taxi to the runway but the weather was warm, like 91F. Would that be a good reason, alone, to leave the gear down so long?

I was sitting right over the wing and gear so I could hear it pretty well.

Cheers,
John

p.s. by chance someone had posted a new thread asking this same question today!
 
tdscanuck
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RE: Why Keep The Gear Down So Long?

Thu Sep 04, 2008 11:59 pm



Quoting UPSMD11 (Reply 9):
We had a long slow taxi to the runway but the weather was warm, like 91F. Would that be a good reason, alone, to leave the gear down so long?

Was it a long flight (for a CR7)? Long slow taxi at high gross weight, plus warm weather, is a good situation to want tire and brake cooling after takeoff.

Tom.
 
upsmd11
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RE: Why Keep The Gear Down So Long?

Fri Sep 05, 2008 2:51 am



Quoting Tdscanuck (Reply 10):
Was it a long flight (for a CR7)? Long slow taxi at high gross weight, plus warm weather, is a good situation to want tire and brake cooling after takeoff.

It wasn't that long, MDT - ATL. That is about 691 miles and about 1.5 hours of flying time.

We ended up going all the way to 38,000 feet during cruise and I know those gear were down until about 10,000 at least.

I could hear something in the wind, wondered what it was and then I heard the gear go up.

John
 
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HAWK21M
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RE: Why Keep The Gear Down So Long?

Tue Sep 09, 2008 12:55 pm



Quoting UPSMD11 (Reply 9):
I was on a flight today (CR7 out of MDT) and the gear seemed to stay down until we were at about 10,000 ft at least, maybe a bit lower.

High Brake Temperatures?
regds
MEL.
I may not win often, but I damn well never lose!!! ;)
 
stratosphere
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RE: Why Keep The Gear Down So Long?

Wed Sep 10, 2008 12:56 am

On a test flight anything goes basically.. But in the revenue world I have seen both gear slow to retract ( usually brake cooling) and I have seen gear dropped way early. I was on a NW DC-10 into MSP that dropped the gear with no flaps pretty high up. The Capt came on and said we were a little high and he would be dropping the gear to lose altitude.
 
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HAWK21M
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RE: Why Keep The Gear Down So Long?

Wed Sep 10, 2008 1:26 pm



Quoting Stratosphere (Reply 13):
I was on a NW DC-10 into MSP that dropped the gear with no flaps pretty high up. The Capt came on and said we were a little high and he would be dropping the gear to lose altitude.

Were Spoilers deployed too?
regds
MEL.
I may not win often, but I damn well never lose!!! ;)
 
UAL Bagsmasher
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RE: Why Keep The Gear Down So Long?

Wed Sep 10, 2008 1:59 pm

UPSMD11, chances are the aircraft in question had an MEL for the MLG bay overheat system. One of the stipulations is that the gear must be left down for so many minutes to ensure proper tire and brake cooling, since you have no way of knowing if that gear is overheating with the overheat system MEL'd.
 
Rj111
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RE: Why Keep The Gear Down So Long?

Wed Sep 10, 2008 4:05 pm

Is there a speed limit with the gear down?
 
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HAWK21M
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RE: Why Keep The Gear Down So Long?

Wed Sep 10, 2008 8:15 pm



Quoting RJ111 (Reply 16):

Is there a speed limit with the gear down?

There Def is....apart from providing drag,you don't want the L/G to be subject to damage due to high relative airlow.
regds
MEL
I may not win often, but I damn well never lose!!! ;)

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