Can anyone comment if this is how TCAS works, does it purely rely on the Transponder signals? That strikes me as logical.

You are correct, the TCAS system works by “talking” to the other aircraft that are transmitting. By transmitting altitude, speed and climb rate each TCAS can calculate and notify each pilot of the appropriate avoidance climb or decent rate needed. Both the TCAS systems involved also notify each other what they are telling their respective pilots to do to avoid both telling their pilots to climb or descend. By not having their transponder on the Legacy pilots would be invisible to other TCAS systems in the area leaving the pilots to rely on their eyes only.

Here’s the picture from the article as well as 2 others that I found online.

It appears that they suffered some damage to their elevator.

I can’t recommend “The High and the Mighty” enough starring John Wayne. It’s a film adaptation of a novel by Ernest Gann. If you haven’t he’s novels are a must read for any aspiring commerical pilot. “Fate is the Hunter” is Gann talking about his experiences as a new airline pilot post WWII when commerical aviation as we know it was getting started. What he writes is outstanding since it’s about pilots written by a pilot.

I think attempts at giving outsiders a look into the inner workings of the cockpit environment don’t try to justify their mistake but paint a picture where it shows how cascading system/CRM/decision making errors can be masked by routine activities.

I hope they find more, what a tragedy.

Land the plane, it’s as simple as that.

Any talk of arming pilots in the EU?

The idea isn’t new

No, but actually arming pilots is (with a few acceptions).

it would seem most pilots don’t want it

I think the reality is quite the opposite. There are quite a lot of hoops that must be jumped through until a pilot is authorized to carry so that can be a reason someone isn’t armed. Just getting the time off for training is something not every pilot can do.

because a shootout in a cockpit is always a bad idea

Or so says Hollywood. Airplanes aren’t made of glass and won’t fall out of the sky at the slightest damage, gun related or not.

because the majority of pilots does not have any kind of regular practice with firearms, unlike the marshalls.

Any armed pilot is trained, they aren’t just given a gun and told to show up at work. I believe now that the training is in the same department as the FAM’s. Also the pilot training goes beyond just firearm training and really deals with protecting the flight deck. Why some are against such measures is beyond me.