It is important to separate acceleration issues from V1 - control and aircraft performance.
Without probability statistics, coupling accel and V1 generates mind-cluttering uncertainty.
For those of us who can remember the days of Vstop and Vgo for contaminated operations, V1 has safety benefit, and clarity and simplicity in decision making. Unfortunately the latter has been eroded with extreme 'what if' scenarios and the appalling 'except' caveat originating from the US unions.
We should remind ourselves that engine reliability is significantly better than when V1 was a critical issue; also that modern aircraft are generally easier to control and operate.
Over focus on 'system failures' or situations which defy clear understanding or implications may contribute to incorrect choice of action: e.g. as previous observations on 'tyre failure' - how do you know (and any discussion or deduction before replying should take less than 1 sec)
The missing SOP is "I don't know'. We hate uncertainty thus make it up - we justify actions which in hindsight might be judged negatively.
Last edited by safetypee; 1st October 2025 at 12:13.