@Yoshi:
Yes this is a valid move, since you may ignore a sub or a tranny when making your moves.
I believe Kreig has already answered a similar question in this thread, but I will admit I’m too lazy to find it ;)
That’s the 3rd affirmative reply you’ve received, Bardoly. If you aren’t satisfied until Krieg answers your question, than just say so. We understood your question. The answer is yes, it’s legal.
Attacking the sub doesn’t make the zone a “combat zone” that your transport can then not load units and pass through. Krieg already explained that combat doesn’t happen until the combat phase. This is the combat movement phase. Z49 is friendly and your transport can pick up units, and your destroyer can make a combat move on the sub at the same time. So game on, already! :-)