Bookworm,
Any twin engine aircraft engine failure below VMCG the immediate reactions are close throttles, maintain directional control and stop ahead.
The same applies to a failure below VMCA
The twin comm's performance category means that it is likely that a forced landing will be required with an engine failure shortly after take-off. With that in mind, there is no advantage or loss in permitting the aircraft to become airbourne before in this case VMCA.
In fact provided that the immediate reaction to an engine failure is to close both throttles then it is just as safe to become airbourne below VMCA and accelerate in the climb to 50ft - the take-off distance figures would allow for this, than to try and keep the aircraft on the ground resulting in a wheelbarrowing situation.
Ever seem a twin comm have an engine failure below VMCA with just the nosewheel firmly on the ground? Not something I would like to try.
If it is a long runway and you are airborne in something like a fully laden senneca 1 and at Blue line speed, I would keep the gear down until there is no longer a posibility of landing back on the runway because if one engine fails, I am going to land back on as long as runway is available.
Thus as has been said earlier, light twins are esentially no better than singles until cleaned up, well established in the climb and of course in some cases at less than MTOW.
Just to make it interesting you should note that there are aircraft where VMCA is less than VMCG.
In FAR-25 aircraft, being performance A category V1 must be a factor above VMCA / VMCG. This requirement ensures controlability in the event of a stop as well as a go decision.
Up to V1 - stop. After V1 - go.
As has been said earlier also, the VMCA / VMCG figures are simply baselines that determine the operational speeds.
To put it in simple terms - your rotate speed in a C172 is a factor of the stall speed but you don't particuluarly note the passing of the stall speed during the take-off roll - you simply concentrate on acheiving the rotate speed and safely departing.
Regards,
DFC