There are a number of reasons for SAS 737NGs not having winglets:
1. The 737-600s are not certified with winglets.
2. SAS has only selected to install winglets on aircraft that don't need to strengthen the wing (to save expences), and that means only -700s later than L/N 1545 and -800s later than L/N 778.
3. Then there is an engine issue. SAS selected DAC (Dual Annular Combustor) versions of the CFM56 for their first batches -683, -783 and -883 (the 737-705 that came from Braathens Single Annular Combustor engines), and it happens to be only aircraft with SAC engines that are certified for winglets.
This is only some of the reasons for having and not having winglets installed at SAS. Within the 737NG fleet there are more differences, like some aircraft have Atlas galleys while other have KSSU galleys. Then there are different seating configurations within each sub series, different engine ratings and different MTOWs. Fleet commonality is unknown to SAS.
Last edited by LN-KGL; 19th Dec 2012 at 22:21.