Does Size Matter: A Landing Gear Question?
07-11-2008 | 04:54 PM
#1
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From: C-172
Does Size Matter: A Landing Gear Question?
My office is about 10 miles south of SeaTac airport. When I go outside and look up, I see planes coming in to land. Lots of them. They are right on top of me to the point where I sometimes cannot tell which airline because all I see is the belly.
The other day, a CAL 737 was coming in and I noticed it did not have its landing gear down. I thought it was getting mighty close, but sure that it will come down in due course. Today, the daily BA 747 was arriving from London. I know that because it turned a little bit and I could see its tail. I noticed that it had all its wheels down. Hmmm.
When are the wheels supposed to come down? Why the difference with these two? Could it be ... no, it can't be.
The other day, a CAL 737 was coming in and I noticed it did not have its landing gear down. I thought it was getting mighty close, but sure that it will come down in due course. Today, the daily BA 747 was arriving from London. I know that because it turned a little bit and I could see its tail. I noticed that it had all its wheels down. Hmmm.
When are the wheels supposed to come down? Why the difference with these two? Could it be ... no, it can't be.
07-11-2008 | 05:04 PM
#2
Gets Weekends Off
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My office is about 10 miles south of SeaTac airport. When I go outside and look up, I see planes coming in to land. Lots of them. They are right on top of me to the point where I sometimes cannot tell which airline because all I see is the belly.
The other day, a CAL 737 was coming in and I noticed it did not have its landing gear down. I thought it was getting mighty close, but sure that it will come down in due course. Today, the daily BA 747 was arriving from London. I know that because it turned a little bit and I could see its tail. I noticed that it had all its wheels down. Hmmm.
When are the wheels supposed to come down? Why the difference with these two? Could it be ... no, it can't be.
The other day, a CAL 737 was coming in and I noticed it did not have its landing gear down. I thought it was getting mighty close, but sure that it will come down in due course. Today, the daily BA 747 was arriving from London. I know that because it turned a little bit and I could see its tail. I noticed that it had all its wheels down. Hmmm.
When are the wheels supposed to come down? Why the difference with these two? Could it be ... no, it can't be.
There's no "standard" or requirement. The vast majority of airline pilots, though, typically put the gear down at or shortly before the outer marker, which typically is about 5 miles from the landing threshold. I've flown everything from DC-9's to MD-11's, and we do them all the same. Of course, if you are high/fast, you might put them down sooner to help you slow down.
Pine
07-11-2008 | 05:08 PM
#3
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From: Lead Guitar
My office is about 10 miles south of SeaTac airport. When I go outside and look up, I see planes coming in to land. Lots of them. They are right on top of me to the point where I sometimes cannot tell which airline because all I see is the belly.
The other day, a CAL 737 was coming in and I noticed it did not have its landing gear down. I thought it was getting mighty close, but sure that it will come down in due course. Today, the daily BA 747 was arriving from London. I know that because it turned a little bit and I could see its tail. I noticed that it had all its wheels down. Hmmm.
When are the wheels supposed to come down? Why the difference with these two? Could it be ... no, it can't be.
The other day, a CAL 737 was coming in and I noticed it did not have its landing gear down. I thought it was getting mighty close, but sure that it will come down in due course. Today, the daily BA 747 was arriving from London. I know that because it turned a little bit and I could see its tail. I noticed that it had all its wheels down. Hmmm.
When are the wheels supposed to come down? Why the difference with these two? Could it be ... no, it can't be.
07-11-2008 | 07:08 PM
#7
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From: Executive Transport Driver
Personally, when I drop the landing gear is a function of many factors. In this day and age of fuel conservation and high operating costs, I try to minimize the amount of time flying around with the gear down.
Operators have operating profiles that call for the landing gear at specific intervals. These often have allowances for crew preference or operating conditions such as a long final or speed restrictions.
Typically pilots will drop the gear after adding some degree of flaps, however the gear can also be used to slow the plane down (such as if it is heavy). Either way, the gear will need to be down by an arbitrary speed (in my aircraft it's 150 knots) or the gear warning horn will sound. The warning horn will also sound if full (landing) flaps are selected and the gear is not down.
Operators have operating profiles that call for the landing gear at specific intervals. These often have allowances for crew preference or operating conditions such as a long final or speed restrictions.
Typically pilots will drop the gear after adding some degree of flaps, however the gear can also be used to slow the plane down (such as if it is heavy). Either way, the gear will need to be down by an arbitrary speed (in my aircraft it's 150 knots) or the gear warning horn will sound. The warning horn will also sound if full (landing) flaps are selected and the gear is not down.
07-11-2008 | 10:29 PM
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Different procedures at different airlines; also some airports have their own requirements. For example flying into Narita-Tokyo when coming from Anchorage we are supposed to drop the gear pretty early, prior to reaching the shore line.
This, I think, is to prevent ice chunks falling off the gear onto houses in the neighborhood... We’re especially protecting that one dude who has a “Down with Narita Airport” banner hanging from his fence…
Also, some airlines save lots of fuel by keeping the gear up all the way to the ground. I think it's called cost index "ground neutral".
http://media.myfoxboston.com/images/...irlines500.jpg
This, I think, is to prevent ice chunks falling off the gear onto houses in the neighborhood... We’re especially protecting that one dude who has a “Down with Narita Airport” banner hanging from his fence…
Also, some airlines save lots of fuel by keeping the gear up all the way to the ground. I think it's called cost index "ground neutral".
http://media.myfoxboston.com/images/...irlines500.jpg
Last edited by ⌐ AV8OR WANNABE; 07-11-2008 at 10:38 PM.
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