scenario:
Aircraft 320 G.W= 72T V1/VR/V2 = 145/145/150 ( ASDA) RWY= 3500M
hypothetically
an emer elec config condition given at 140 kts with nearly half the runway behind. You elected to continue due to the degraded braking performance and reduced stopping dist avail. as the BSCU systems are inop and only manual braking is effective to a max 1000psi.
My question is that the certification of an aircraft with regards to v1, to my knowledge, is bascially based on the worst case failure happening at v1 and being able to stop the aircraft within the remaining dist available. Most example are based on and engine failing at v1 at max tow etc.. ... .....
However the airbus case is .........
Looking into the QRH Abnormal Elec Emer. Conf. at 72t produces a vref of 142kts and a Actual landing dist Req. approx 2800m (Landing dist is factored by 2.5)
if we simplify the physics an aircraft landing at 142kts and rejecting at 140kts will have the same momentum (disregarding gravity). Hence logic would say that you would need 2800m to stop the aircraft if such a failure occurred near v1 (140kts).
BUT as we are told any MAJOR FAILURE below V1 we are instructed to reject the takeoff ....
During such a failure with the cockpit light and screens going blank to a degree added the stress and uncertainty of the situation, One would instinctively reject the takeoff and if so would certainly run off the end of the runway.
now considering the situation how valid would be the V1 value taking into account this particular failure...
i been going over the Airbus manuals and nowhere does it instruct or inform the crew to the relationship between the particular failure, v1 and or decision to go. From what i have seen all scenarios regarding this failure are based whilst the aircraft is airborne.