Dave, or "Phineas" or "Tolstoy" or,
If you have a crew card attached to a ship, you can discard it to use its ability (OPS, COMBAT, etc.). Does this count as playing a command card during a test? Or can you discard your crew card (attached to a ship) and still play 1 command card (from your hand) ? Thanks for any help on this.
The bold part of your question is true. You can indeed do that. Though if you discard a Crew Card, be sure not to also count its benefit that it grants while on your Ship. I believe there is an example in the Rules about that, page 27. (I edited your question slightly.)