Performance
Ok having a look through the flight manual of a B2 BK117 Cat A operations into Wellington are not problem.
Empty weight 2000kg, Pilot 95kg, Patient 95kg, Crew 190kg, Fuel 380kg, EMS kit 200kg?
Total weight 2960kg
Looking at the graph the BK could maintain Cat A performance up to 37 deg C at this weight.
On a more realistic 25 deg C summer day 3200 kg is achievable at 1000 DA.
This is a B2 that has an OEI torque limit of 125%. Carry out service bulletin 117-125 and this is increased to 140%