Runway Light Question

[PhatAJ2008]

Not to be repetitive, but I was plane watching last night at TIA. I don't know how many of you are familiar with that airport, but they have two parallel runways, one being much longer than the other. The longer one has those lights up on poles the gradually get closer to the ground following the planes final decent probably two hundred feet before the runway. The shorter runway doesn't have these... I have seen at other airport that runways shorter than TIA's short one do have them... Why do certain runways have them and others don't? Also was at the south end of the longer runway last night with planes landing from the south and those lights, nor the strobes on them were functional... Do they only use them in poor visibility?
-AJ

 

[great cornholio]

Those lights are called approach lights. They are found on runways that have an ILS (Instrument Landing System) to them. Not all runways have an ILS. An ILS is used in poor visibility the weather can be down to 1/2 SM vis and 200 ft overcast and you can still land from an ILS. In the cockpit you see 2 needles one needle stands up and down and the other one lies horizontal. The vertical needle will show if you are lined up with the runway or if you are off to the left or right of the runway. The horizontal needle will show you if you are too high or too low on the final. When everything is perfect the 2 needles should make a perfect cross and meet in the middle. The approach lights help you pick up the runway because that strobe light is usually the first thing you see if the weather is really bad. The use of the lights depends on the airport. If the weather is bad then they will be on day or night. If the weather is good most airports have the steady lights on at night and only use the strobe part if the weather is bad. If a pilot wants to turn them on then they can ask to control tower and they will turn them on for us so we can find the runway easier. Hope that helps have fun.

 

[A1FlyBoy]

Follow the ball....