What causes the BANG when an airliner lifts off?

As long as you are sure it isn't the wheels completing their retraction into
the wheel well, then it is probably the struts extending to its
full-extended position. Or it may be the brakes stopping the turn of the
wheels before it starts its retraction. I've flown many hours around the
world and the main "bang" I remember is the retraction of the main wheels.

Marco Leon

"G Farris" wrote in message
...
I've flown a lot of planes, of different sizes, and I always lift off
gently.
When I fly as a passenger on an airliner though, there is a "thud" or even
a
"bang" as the main wheels leave the runway. Sometimes this bang is so loud
is
frightens passengers, and once it was strong enough (on a 777 departing
for
Hong Kong) that I was sure we'd at least blown a tire, if not actually
struck
something with the mains. But in the end, it's always OK - just normal.
Who
knows what this is? Is it the pusher actuators on the main gear? The
telescoping elements of the main gear bottoming out? Just curious. . .

G Faris