Hi,

R2D2 (Crew) recovers 1shield at the End of the Endphase and rolls a "Hit". You flip one Damage card with the pilot trait faceup. Can you discard this card (Determination)? Thus you get 1 shield and 1 hull point back?

Thanks

Flipping and dealing a card are not the same thing, so no. Determination only works when the card is dealt to you face up. The same goes for chewbacca's (pilot) ability.