Right. Thanks BOAC. So when you use that procedure, do you spool up to 70% with the brakes on, hold it for 30 seconds, and then release the brakes and select T/O thrust (i.e. still only two power settings)? OR do you still go to 40% first, 70% second, then T/O thrust (i.e. three power settings)?
Are the brakes able to hold the aircraft completely stationery at 70% for 30 seconds?
And, would you brief the passengers that they are in for a 'fun take-off' (rephrased to sound professional and reassuring in a deep gravelly voice, of course
)?