I was controlling a westbound Concorde just entering my airspace when I received details of an SR-71 coming eastbound on a route that would conflict with Concorde. The SR-71 did not always fly supersonically, it was doing less than Mach1 on this day, but it was still at a very high altitude. I had been told it was “above 600”, i.e. above 60,000ft. Concorde was operating up to 60,000ft and the vertical separation standard at that altitude was 4,000ft.
I sent a message to the American radio operator to ask for the exact altitude of the SR-71. A few minutes later the answer came back, “Above 600.”
I telephoned the radio operator explaining I needed the exact altitude. The radio operator’s response was, “I’ll patch you through.” The operator had a facility to operate a 2-way switch on the radio. Push it one way and you could transmit over the telephone, switch it the other way to receive. At the end of each transmission you had to remember to say “Over’ in order for the radio operator to know when to flick the switch.
I was now talking directly to the pilot of the SR-71. “This is the Shanwick controller, Confirm your altitude. Over.”
SR-71: “We are above 600. Over.”
Me: “I need to know your exact altitude. Over
”SR-71, “Above 600. Over”.
Me: “Am I to understand you are unable to give me your exact altitude? Over
”SR-71, “Affirmative. Over”
(These aircraft had a stealth capability and could fly at very, very high altitude, often above 70,000ft. They did not, however want anyone to know exactly at what altitude they were flying so would switch off their radio signal that would indicate altitude to a radar operator once they climbed.)
Me, “OK, I have a Concorde operating westbound on a conflicting route with you at 60,000ft. I need 4,000ft vertical separation. Do I have it? Over”
SR-71: “You sure have.”
Me: “That’s all I need to know. Thanks. Out”
Just another little moment to brighten my day.
– Copied from Pete Clarke –