Originally Posted by
RAFEngO74to09
Another take on the mid-air - making the following points:
- Although the handling pilot of the helo is at fault having accepted responsibility for maintaining Visual Separation, this analyst believes ATC should not have given the helo the clearance to maintain Visual Separation at night - especially at the closure speed the aircraft were at which he estimates as at least 280 knots.
- The helo pilot appeared to request Visual Separation too quickly - if she/he had not and stated they were trying to establish Visual Separation, ATC could have had the helo turn 90 degrees or the helo could have gone into the hover.
- Limited cockpit visibility forward in a UH-60 - especially when nose down searching for an aircraft higher.
- If an incorrect barometric pressure is set, this does not just make the aircraft altimeter read incorrectly but the ADS-B that feeds ATC as well.
https://www.youtube.com/watch?v=X3PtOdR_VCc
It would take at least 20 seconds to bring a helo to the hover from the (publicly available) forward speed of over 100 kts. And no sane helo pilot would attempt such a manoeuvre at 200 ft at night.
ADSB-transmitted altitude is based on 29.92 in / 1013.2 mb regardless of what is set on the encoding altimeter subscale.