I was lucky enough to be trained to do this a few years ago out of Albuquerque, in my case using a USAF Blackhawk.
The maximum speed of the helicopter is close to the minimum speed of the C-130 so the initial formation is achieved by the heli flying S & L at an assigned altitude at 130 kts. The C-130 then flies about 300ft above and overtakes directly ovehead. It is quite an impressive sight from inside the helicopter! The heli is then manoeuvred upwards and forwards to make the connection. Obviously R/T contact is used between the two aircraft and there is also a homing system but I can't give any details of that.
The heli probe does extend but in the case of the Blackhawk it does not extend beyond the rotor tips; so it is important not to get vertically out of station when close to the basket, for obvious reasons
The helicopter flies to the basket from immediately behind with the rotor disc over the top of the hose, which curves down from the C-130 but levels off to almost horizontal near the basket. Actually, two aircraft can be in trail as there are two hoses, one each side of the C-130. The port station is easiest to fly as the propwash of the mothership affects the starboard side more. A slight overtake speed is required to "stab" the aircraft probe into the centre of the basket, which both locks the probe on and opens the fuel valve. I was very surprised
to see a 2 foot long static discharge spark between the end of the probe and the basket just before we made contact, especially as it was dark and we were using NVGs. The IP I flew with was grinning from ear to ear at my exclamations as he knew exactly what was about to happen. Thanks for not telling me Dave!
It is not an easy thing to do, it requires very good close formation skills and a cool nerve.
Well done the yanks, wish I was there!
