Originally Posted by
Going Boeing
I believe that the main issue for the B787 is the "Return to Land" function in the OTP. The certification requires the aircraft to be able to land back at the departure airport after reducing fuel load to below MLW. In JNB, the obstacle clearance in the missed approach is the main issue that results in restricting the the allowed MBRW to be marginal to fly to SYD, can make PER with no problems.
Not exactly Going Boeing,
FAR25.1001 states the aircraft must be capable of performing a one engine inop go-around with a minimum of 2.1% at the same airfield it has taken off from considering 15 minutes fuel burn plus 15 minutes of fuel jettison.
No requirement to land below MLW as you state.