I know it doesn't make any difference to the landing, but I like to do these things properly anyway,  when abouts do commercial airliners put their landing gear down?  Is it at a certain Alt. or a certain distance from the runway? Thanks

It is a little of both. Speed is the key factor here you do not want to lower your gear if you are going to fast no matter at what altitude. But in the real world there is a 250 knot air speed restriction below 10,000 feet.
Different airports have differnet altitude requirements for approach. You certainly would not want to fly 1,200 feet while on approach to JACKSON HOLE WYOMING if you try you will be burried in the ground by 5,000 feet or so. Since the altitude of KJAC is 6,412 feet AGL. So as a plane desends below 10,000 feet it slows down to at least 250 then the flaps usually go down next followed by the gear a little later.

Normally you would not lower the gear before flaps 5 is selected (or normal LLZ intercept config). But when the GS becomes alive select gear down and flap 15 and arm the speedbrakes

But in the longer 737's, which are very slippery and difficult to slow down, lowring the gear is a great way of getting rid of excessive energy. Works in speeds below 270KIAS  Just watch the approaches into Innsbruck when gear down is selected at 9000ft 

Quote:


On your PFD, assuming a normal ILS approach (not B/C), the pink diamond (on the glideslope indicator portion) will be above the center by 1 1/2 tick marks.

I was in a 747 a couple of days ago landing at JFK... I was right next to the wing and I could tell when the pilot put down flaps 15... it was at about 2500 ft., a good 5-7 minutes before touching down... at 2000 he lowered the gear... I was looking at the TVs behind the seats for the stats on the flight...

I'm pretty sure that most other airliners follow the same procedures... but then again I'm not a professional...