3 ms·

100 ft. of separation is an idiotic safety margin.

loeg 2y ago
Yes -- 500 ft is considered inadequate in general.
b_t_s 2y ago
The combined height of a blackhawk and a large jet is about 60ft. The combined length is a bit over 300ft, and since neither aircraft is unlikely to be level, some portion of that length gets contributed to their effective height while flying. Just given the size of the aircraft, I wouldn't be surprised if they can potentially overlap even if their altimeters are 100ft apart.
dghlsakjg 2y ago
That wasn't the safety margin. That was the altitude discrepancy that was left after the Helo disregarded or misinterpreted ATC directions and flew where they specifically were told to avoid.
- kevin_thibedeau 2y ago
  If the airplane was on the correct approach at 300 ft. and the Blackhawk was restricted to 200 ft. the margin is 100 ft.
  - dghlsakjg 2y ago
    No, The Blackhawk was supposed to be at a different altitude AND a different location. The loss of separation was not primarily because of the Z axis, but because the Blackhawk was in the wrong spot on the X,Y axis. The controller said, paraphrasing ATC speak, "Do you see that plane? You are cleared through the airspace as long as you see and avoid that plane by going behind it. You are responsible for separation if you accept this". The BH pilot responded, "I see the plane, I can and will avoid it. It is my responsibility to go behind it, and I will do that." The collision would have been narrowly avoided if the Blackhawk was at the right altitude, but that was the last in a long line of piloting errors that caused this midair. If they were at the correct assigned altitudes it still would have been an incident because the loss of separation wasn't about the altitudes, it was about the errors made long before then. They weren't cleared to be where they were, and no controller would allow an altitude only separation of 100ft. Simply put, that helicopter pilot was specifically not supposed to be where they were, and the standard separation was violated before the altitude became an issue. If you narrowly miss someone driving down the wrong side of the highway after crossing the medain, the margin of safety isn't the distance that you missed that car by, it is the median.

loeg 2y ago

Yes -- 500 ft is considered inadequate in general.

The combined height of a blackhawk and a large jet is about 60ft. The combined length is a bit over 300ft, and since neither aircraft is unlikely to be level, some portion of that length gets contributed to their effective height while flying. Just given the size of the aircraft, I wouldn't be surprised if they can potentially overlap even if their altimeters are 100ft apart.

dghlsakjg 2y ago

That wasn't the safety margin. That was the altitude discrepancy that was left after the Helo disregarded or misinterpreted ATC directions and flew where they specifically were told to avoid.

kevin_thibedeau 2y ago
If the airplane was on the correct approach at 300 ft. and the Blackhawk was restricted to 200 ft. the margin is 100 ft.
- dghlsakjg 2y ago
  No, The Blackhawk was supposed to be at a different altitude AND a different location. The loss of separation was not primarily because of the Z axis, but because the Blackhawk was in the wrong spot on the X,Y axis. The controller said, paraphrasing ATC speak, "Do you see that plane? You are cleared through the airspace as long as you see and avoid that plane by going behind it. You are responsible for separation if you accept this". The BH pilot responded, "I see the plane, I can and will avoid it. It is my responsibility to go behind it, and I will do that." The collision would have been narrowly avoided if the Blackhawk was at the right altitude, but that was the last in a long line of piloting errors that caused this midair. If they were at the correct assigned altitudes it still would have been an incident because the loss of separation wasn't about the altitudes, it was about the errors made long before then. They weren't cleared to be where they were, and no controller would allow an altitude only separation of 100ft. Simply put, that helicopter pilot was specifically not supposed to be where they were, and the standard separation was violated before the altitude became an issue. If you narrowly miss someone driving down the wrong side of the highway after crossing the medain, the margin of safety isn't the distance that you missed that car by, it is the median.