An inlet cowl is quite heavy
No it isn't!
Inlet Cowl: 315kgs GE 355kgs Trent
Fan cowls: 140kgs GE 115kgs Trent
T/Rev halves: 800kgs GE 650kgs Trent
Trent 895 95k lbs of thrust (BET will be lower*)
The Trent weighs in at 7136kgs as an EBU (that includes all the boeing fit
components, so thats the nose cowl, IDG and hyd. pump).
The GE90 weighs in at 8500kgs as an EBU.
The base engine ranges from 76k to 94k*
*Boeing equivalent thrust (BET) is a calculated number. It is equivalent to
the thrust at 165 knots at sea level. BET is defined so that engines with the same BET will have the same TO perf. at sea level.
As TURIN says. The Triple spool needs a lot less air to start than the '90. A dual engine start is easily achieved on the Trent (I always do dual starts).
An inop APU can be a real PITA down route as you also need three ASU's for the GE90
