V1 speeds below Vmcg
A recent discussion with some colleagues regarding the HS125-800XP business jet raised the issue of the scheduled V1 being below the published Vmcg for the airplane. (or aeroplane!)
A review of FAA CFR 14 part 25 (amendment 42) and AC 25-7A (part 25 certification flight test guide) seems to indicate that V1 must always be greater than Vmcg by a small margin. (5% perhaps?) The problem is that when following the instructions for use of the AFM performance charts to be used in determining V1, Vr and V2, the resultant speeds are well less than Vmcg. This is particularly so at higher field elevations and temperatures. In some cases, the scheduled V2 is below Vmca. In all cases, the v-speeds derived are at least equal to the "minimum" V1, Vr and V2 curves depicted on the chart.
So my question is whether such a circumstance where these performance speeds being below the associated minimum control speeds was allowable under the original certification criteria. It's understood that the original certification of the 125 series back in 1962 or so did not take place under the current certification regulations. Was this formerly allowed? And did the 800XP have to meet later amendments to the regulation than earlier models?
Thanks in advance.
Best regards,
Westhawk