Originally Posted by
treadigraph
I seem to recall damaged winglets have occasionally been removed before a revenue flight and the aircraft flown home?
The winglets were on the MEL/CDL/DDG - dispatch was allowed for (I think) 10 days - I don't recall if it was for one or both missing... The short range -400 didn't get winglets (IIRC JAL did something where they used 747-400s for short range service until they got up to a certain number of cycles, then converted them to long range aircraft to get the hours out of the airframe - rather clever).
Originally Posted by
treadigraph
Why did the production 747-400 and 800 freighters not have the stretched upper deck? Keep airframe weight down a bit to improve loads carried on the main deck?
Yes, I believe it was airframe weight - they couldn't use the additional space and the extra airframe weight meant less cargo. Also, the cargo operators are less concerned about cruise speed - apparently cruising around at 0.80 to 0.82 is pretty common for a 747F while passenger aircraft seldom go that slow - and the area ruling benefit comes into play at about 0.84.