Originally Posted by
Mooncrest
How is the MTOW of a single-design aeroplane varied anyway ? I remember when Air UK Leisure received its 737-400s, there was some company literature (inflight magazine, perhaps) stating that two of their newcomers were a certain weight, but the other two had a higher weight and could therefore go further.
I think the 737, with all its variants, is about as far from a "single-design" as you can get. Even within a single series, the manufacturer will typically offer weight/price options (which will be expanded as development and service experience progresses), and operators also have an incentive to certify individual fleet members at a lower MTOM in order to reduce landing fees, route charges, etc.
An extreme example is the MD-81/82/83 series where recertifying an aircraft from, say, an MD-83 to an MD-82 (or any other combination) is purely a paperwork exercise.