Originally Posted by 11atsomto

If you really read FAR 117 carefully......and I will contend many people have not and that's okay. However many will be surprised to find out that a crew extending or NOT extending is actually a Captain/PIC decision. Now as a matter of good CRM and maintaining a good reputation most Captains will/should gauge the opinions of thier FOs/IRO's but there is no legal requirement for them to do so.

If a FO or IRO does not wish to extend and the Captain does, their only option is to call out fatigued, or call Pro Standards or something.

I certainly don't agree with this but it is what it is. Some may say what's the difference. The difference is that a fatigue has two possible outcomes: APPROVED or NOT APPROVED. where as a FAR 117 non Extension is an outcome all in to itself.