I am a little confused between the MTOWs of the 747-300 in comparison to the 747-300SR. There is a major discrepancy between the various fleet lists about which airframes are -300 and which ones are -300SR versions from JAL.
ACAS (Flightglobal) e.g. reports only two airframes being -300SR versions (5N-DBM with Maxair and VP-BGW with Transaero). Their MTOWs are quoted as 371’946.
I have flown on Transaero’s VP-BGU, a regular -300 which in return is quoted with an MTOW of 310’000. I have also flown on QF’s VH-EBY which has an MTOW of 377’843 according to ACAS.
Could someone clarify why the -300SR version has a higher certified MTOW than the regular -300? Is possibly the strengthening of the airframe for the shorter FH/Cycle ratio of the SR that heavy?
Thanks for your comments.