Originally Posted by
physicus
All Boeing products
afaik turn in the direction closest to the HDG target in AP HDG mode. So to turn left to 180 from 90, you would need to turn the heading bug left to 350ish degrees, wait until close, then continue the knobbing left to 180. But I don't suspect any of us know what AFS lateral mode they were in. Likely HDG mode, but we don't know.
I was thinking maybe the Boeings turned in whatever direction the heading bug went for a turn of more than 180 degrees. In other words, if you start cranking the heading to the left, the plane banks left and will not reverse turn direction if you continue turning the heading knob more than 180 degrees from the current heading.
But, I'm not sure. Some of this detail stuff on the avionics and automation is 'pin selectable' like the single cue or crosshairs flight director. And some of the autoflight behavior is subtly different with with different engine and airframe combinations.
So I do exactly what you describe, walk the heading bug around keeping it less than 180 degrees from the aircraft's passing heading.
Originally Posted by
Hotel Tango
And indeed, as mentioned by Uplinker, the EVA initially turned left and flew on a heading of approximately 018. So, did they hear "left heading 180" and, instead of confirming with ATC, put the emphasis on left and decided "oh she must mean 018"? Who knows
I'm trying to think if I've ever had a heading like 018 (other than maintain runway heading) given for vectors in airline flying. If that's what I thought we heard, like everyone here says, I would question and confirm.
Also, is there an ICAO ATC phrase that implies 'turn the long way around'?