We asked Sikorsky for an answer and they ruled that 11,700 lbs is the maximum for taxy and take-off because of the landing gear and wheels structure; though declined to add any clarification to the RFM - Ramp Weight or whatever.
Sikorsky reply:
Weight limits are ruled by Part 1, Section 1 of the RFM,Sikorsky cannot allow taxi of the aircraft over 11,700 lbs without an RFMchange.
During initial flight test programs, the structural and much of the performance work were done at GW + 3% on takeoff, however, tocertify this capability the landing gear assemblies and the backup structure stresses will have to be tested and substantiated to the FAA that it's good for2 G taxi loads up to the increased GW.
Last edited by tistisnot; 27th Jun 2013 at 16:26.
Reason: Including Sikorsky reply