The first time was for basically NO REASON. I thought the second time was for even less reason, but then I stared at the page and saw that he ues his shirt to tie the ship's yoke into place so that it doesn't crash.

BUT STILL, IT MEANS HE SPENDS THE REST OF THE ARC WITHOUT A SHIRT!!! Now, when do we get to see Silver without a shirt, huh? Or LANCE??? (I haven't seen Lance since the GSC arc! I miss him! D8)