Thanks 4Real for the info. I read a report somewhere this am that the PAT25 crew were using night-vision equipment. Have you heard that? I would imagine that could have some implications.
I haven't heard anything about NVGs, although it wouldn't be unusual for these crews to do so. Depending on type, they can be prone to light saturation which could be distracting.
I heard the plane probably had its collision detection system off because it doesn't work well at low altitudes, but does ATC have any kind of system to warn about an impending collision? They didn't have much time to react to the misunderstanding, but it seems there should have been, in an ideal world, an alert that the problem had not been corrected, or is that beyond the capabilities of the systems in use?
TCAS wasn't "off". It's designed & configured to automatically suppress alerts below 500 feet. If you think about it, it makes sense - their extrapolated course is directly toward the ground / airport, so any aircraft on the tarmac with its transponder on is going to interpreted as a potential collision target.
Yes - ATC radars have similar algorithms built in. Back when it was first implemented we called it the "snitch patch" because the avoidance limitations built in were quite commonly at a more conservative threshold than pilots and controllers were accustomed to, so the software would alert frequently. On the radar playback from last night (actual radar, not ADS-B systems that are common on the internet) you can see the target symbol representing PAT25 start flashing red right before the collision. There is a period of about 7 seconds where the controller's display was alerting, but there was no corresponding action from the controller. Again, he may have just assumed it was a "near miss" since the UH-60 pilot had confirmed visual acquisition.
Why not remove the copters from the equation by not allowing them in final approach air space?
That's a good - and entirely actionable - question.
There have been numerous occasions when I was denied airspace transit by controllers - most commonly at TTN. My guess is that the controller was trying to accommodate the Blackhawk because those flights are a common occurrence and considered routine.
100% my own opinion, it was a bad idea. And it was an especially bad idea to hand off separation to the helo pilot. The whole tragedy is avoided with a simple "PAT25, traffic your 12:00 and 1 mile is a CRJ on final to Runway 33. Turn left 20 degrees." That one basic call and 67 people are alive today.
