Originally Posted by
wiggy
What changes are you thinking of?
BA was the/one of the lead customers so it might have been a case of never fly the A variant rather than BA demanding bespoke changes?
One for tdracer perhaps.
Dispatch reliability of the 747-400 was horrid at EIS - something around 80% for the first year. Much having to do with software issues - nuisance maintenance faults and the Central Maintenance Computer (CMC) was a mess. Boeing spent a fortune doing what we called "Block Software Changes" to get the -400 straightened out - EICAS, CMC, FMC, you name it. One of the EICAS updates required a hardware change to go with it - Northwest (the -400 launch customer) didn't want to spend money on the new h/w - so the FAA AD'ed it to make them upgrade (which ended up being a royal pain -
every EICAS update after that needed to get an alternate method of compliance because the AD called a specific EICAS s/w version.
That being said, BA came along about a year after EIS (they were the launch Rolls customer) - a lot of the aircraft issues had been straightened out by then, but the RB211 engine control (FAFC) was a mess especially early on.