I don't want to defend Gulfstream, but that Captain refused to fly an airplane because the TCAS was defered, and the WX was bad. Big deal.
You missed one little detail: the pressurization was also deferred. That means he's stuck below 10,000, in dense GA traffic, moving at ~230 knots, with a broken TCAS.
I would have refused a plane in the same scenario, too.
This is how 121 works, if its deferable, you move on...get the aircraft back to a base, then fight with DX about a swap.
Uhhh... no. If it's deferrable
and safe, you move on. Just as an example, the 1900 allows you defer the very same RMI that's your
only source of nav information in the event of a dual generator failure. And while it's perfectly legal to go at night or in low IMC with that equipment deferred, I won't do it. (And at my previous operator, I've run into exactly that scenario [low IMC], and refused the plane for safety reasons. I waited for the low clouds to dissipate before we took off.)
I'd be really ticked if my flight was cancelled because the TCAS was defered. Talk about unrelaible service.
As I said, it wasn't just the TCAS -- it was several deferred items that added up to an unsafe situation.