Hydraulic Arm 767

[HZ123]

Can someone inform me what the above is at the rear of the aircraft which I assume retracts once the a/c takes off?

[gas path]

'Tis the tail skid, there to protect the fuselage if they overcook the rotation rate!

[nitro rig driver]

also called the donkey's c**k for obvious reasons
only fitted to the 300 and 400 series a/c...some may remember the tristar as well.has a telltale painted mark to see if the crew have indeed stroked it down the runway

[HZ123]

Shoud have guessed that. Thanks