Originally Posted by
tdracer
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).
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.
The MEL stated that you could fly with one off but not both! Go figure!!!
Also, getting the winglet off was a difficult task and if you were down route when it happened you had to watch the duty hours.