I’m trying to understand how the GPS transitions on to the procedure and don’t really get it.
For instance placing the aircraft north of EGBJ at GIKNI. Then seleting the EGBJ NDB 27 with transition GST.
I would think the right thing to do is taking up the hold at GST and then go outbound.
The GPS will make a almost 100 degree turn straight outbound. I thought you needed to be within 30 degrees to go straight outbound?
The GPS isn’t intended to help you with the rules for flying conventional procedures. The rules for RNAV (GPS) procedures allow turns of up to 110 degrees at the IAF. With a typical T-shapes GPS approach, that should never be exceeded. However the GTN 650/750 will just “join the dots” and plot an arc, even if it exceeds 110 degrees.
bookworm wrote:
The GPS isn’t intended to help you with the rules for flying conventional procedures. The rules for RNAV (GPS) procedures allow turns of up to 110 degrees at the IAF. With a typical T-shapes GPS approach, that should never be exceeded. However the GTN 650/750 will just “join the dots” and plot an arc, even if it exceeds 110 degrees.
I have learned to fly GPS approaches as you describe. But else I have used the GPS only in the enroute fase. I don’t have GPSS steering. I thought the advantage with that was that you could use the GPS to guide and track you into the procedure along the outbound leg and then switch to VLOC. I now see that is not the case.
You can, but you can’t do so using the rules for flying conventional procedures.
Conventional procedures use fly-over navaids. Thus by the time you have recognised you have passed the navaid and turned 100 degrees on to course, it’s difficult to re-establish outbound. Hence the 30 degree limit. If you treat the IAF as a fly-by, and anticipate the turn, the outbound leg is plenty long enough to accommodate a 100 degree turn.
