Couple of questions

[G-BURR]

Two questions just out of interest.
1. Do you start engines before, during or after pushback?
2. Is there a specific altititude or time in the flight when Ldg Lights are turned on and off?

Thanks

[Rainboe]

It can be all. If the APU is u/s, it will be necessary to use a ground air start truck and a stationary start is required, then disconnect it when one is started. You can then push back and when brakes are applied, start other engines using a crossbleed start technique. Normal operation is to start during pushback, partly so that the tug does not have the all engines running idle thrust to push against.

Landing lamps for aeroplanes are very expensive. One does not want them on all the time, they can cause unpleasant flashing effects in cloud. Normal procedure is to only illuminate them continuously below 10,000' to enhance collision avoidance. Turning them on at other times to say 'hello' or 'I'm flying over now Mum!' is not unknown, though discouraged.

[tallsandwich]

Landing lamps for aeroplanes are very expensive

Expensive in power consumption terms or expensive in that the lights have a limited lifespan?

[catchup]

Expensive in power consumption terms

[woderick]

They are both, expensive to replace and expensive to run although in the electrically wasteful environment that is an aircraft what's another couple of Kw ?

[Pub User]

KWs don't grow on trees!

That energy has to come from somewhere, and there's only one source.

[AerocatS2A]

Our aircraft have landing lights and flare lights (which are just landing lights set at a more downward angle.) We use one set when below 10,000 and then turn the others on when cleared to land.