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Whoops -A firing that went slightly wrong!

The County class carried out regular -if infrequent- test firings. Before I describe one particular test firing I'd like to point out the differences between the normal operational missile and the telemetry missile used for test firings. This latter type of missile had a telemetry transmitter in place of the warhead, with an explosive break-up unit to ensure the destruction of the missile at the end of the trial.

HMS Glamorgan's test firing number 42 didn't quite go to plan. The target was a Stiletto (remote controlled) target flying at Mach 1.75 at an altitude of 55,900 feet. The range was 49,150 yards at the instant of firing and the Seaslug climbed smartly away, reaching 2170 feet per second at boost separation climbing at about 40°. The sustainer motor ignited and the missile gathered into the centre of the beam and rode it up towards the target accelerating to 2900 feet per second. It correctly armed itself and the fuze functioned as the missile passed within 10 feet of the target.

So far everything had gone to plan; now things started to go wrong. Firstly the ship should have transmitted a break-up command to destroy the missile a few seconds later, but the command was never sent. Secondly the self destruct system (the Break-Up Unit) incorporated a clock but in this case it had not been set which meant that it would only function 222 seconds after firing -long after any Seaslug would have dropped out of the sky. In this case the missile kept on climbing with the ship's Seaslug team wondering what to do. A few seconds after intercept the sustainer motor burnt out, the CFE fired to prevent a candle flame forming, and the Seaslug continued to coast upwards. At 50 seconds it had reached 78,000 feet and 6 seconds later was still travelling at 1350 feet per second. It was another 10 seconds before the gas generator ran out of fuel and the turbine alternator began to run down, at this point the Guidance Receiver detected the loss of power and sent the self-destruct command; by this time the missile was at an altitude of over 85,000 feet.

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Last updated: 23rd August 2012.