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.
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.
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.
AnthonyQ wrote:
The takeaway from this, based on the “correct” technique the C141 should have used, is that for the Gloucester arrival from the North for the NDB27, you should alter course to the West and ensure that you cross the NDB outbound within 30 degrees of the outbound course….. Which is what I would do.
Which is what I did on my IFR checkride :-)
Parallel entry in the hold/racetrack and then straight onto the outbound leg.
pmh wrote:
Searching on the picture you attached let me to some interesting articles.
http://code7700.com/course_reversals.html#entry
The takeaway from this, based on the “correct” technique the C141 should have used, is that for the Gloucester arrival from the North for the NDB27, you should alter course to the West and ensure that you cross the NDB outbound within 30 degrees of the outbound course….. Which is what I would do.
Airborne_Again wrote:
That’s the basic rule for base turns, yes.
thank you.
Searching on the picture you attached let me to some interesting articles.
http://code7700.com/course_reversals.html#entry
pmh wrote:
I’m I correct that you need to do the racetrack or holding if outside 30 degrees of outbound track ?
That’s the basic rule for base turns, yes. But you can alway enter the base turn from the reciprocal of the inbound track even if it differs from the outbound track by more than 30° (not the case for the NDB ay EGBJ).
On the latest version of the GTN software (certified in EASA on April 20th) you can place a hold wherever you like, so it doesn’t matter if they are not coded.
The box will then fly the correct join.
On the ILS27 I can see the racetrack – but it keeps flying straight oubound.
I’m I correct that you need to do the racetrack or holding if outside 30 degrees of outbound track ?
I believe at EGBJ only the ILS 27 Hold has been coded in the Garmin database, holds are not coded for either 09 or 27 NDB approaches.
