Can anyone confirm the requirement that a commercial jet engine must be able to go from idle to full power in a maximum of 8 seconds?Thanks,Paul

I'm not sure if there is a requirement for the engine, butThere is a requirement for performance calculations for the landing climb requirement(all engines operating), which says something alike:requirement:A gradient of not less than 3.2% with:i) All engines operating at the power available 8 seconds after initiation of movement of the thrust control form the minimum flight idle to the takeoff positionii) Landing configurationiii) A climb speed which is: 1. not less than 1.13 Vsr(may be 1.15 Vsr for 4 engine aircraft if application of power results in significant reduction in stalling speed) 2. not less than Vmcl 3. not more than 1.23 Vsriv) Aerodrome altitudev) Ambient temperature expected at the time of landing(JAR 25.119)hope this helps a bit