Thinking back to RAFG in the early 80's, we used to run the Jags every time the bomb-heads fitted an underwing tank. The Jag had white/black/crosshatched dolls eyes for external tank fuel indication. You had to run the engines until the dolls eyes went from black to crosshatched, indicating that you had fuel flow. The trick was to chop the engines the moment the dolls eye went crosshatched and the fuel in the lines ran back into the tank turning the dolls eye black again (full) meaning that you didn't have to get the bowser out to top up.
There was a period around 1982 when fuel was rationed (for financial reasons) so the II ac Sqn CO (Tiger Tim Thorn) decided to fly without the external tanks (less drag, better fuel consumption). Problem was he didn't want to get caught with his pants down on a "no notice" TACEVAL generation so he had the bomb-heads put the tanks on all the aircraft at cease flying and got them to take them all off again in the morning. He was not popular
