The decision was taken after several requests and negotiations with ANS. Although not a perfect solution, TAP will apply fee to bags, not boards; moreover, bags weighting less than 10kg will have a 50% discount; finally, keep in mind that a responsibility waiver is also necessary.
TAP's new boards-on-plane regulation are visionary, when we think of what happened with British Airways, once considered the surfer friendly airline company.
In October 2007, BA simply banned boards on flights. The British Surfing Association then issued a global petition in order to try reversing BA's ban regulation.
ANS website has detailed info regarding TAP's new surfboard rule.