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. :o

Vagabond,

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

Some of us are more willing to show our undercarraige than others.

...before you land!!!:D

Before I forget

when you've had enough of the horn that goes off when your gear isn't down and you're at a certain flap position.

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.

It takes British pilots twice as long to accomplish a task so they have to get it out of the way sooner.

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". :D

http://media.myfoxboston.com/images/...irlines500.jpg

I've been hit by ice from aircraft on final to Seatac before, it hurts. They're always dropping ice on BFIs ramp :)