av8trflying
GPS RNAV approaches are the way to go with the world wide decommissioning of NDBs in particular, and in 3rd world countries it is becoming
virtually the only instrument approach available when away from their main international airport.
This link is probably one of the best at simply explaining the procedure and terminology, and the human factors side of it as alluded to by old akro.
http://www.casa.gov.au/wcmswr/_asset...jan/page37.pdf
At the time this was written, they were called GPS NPA.
The GPS RNAV approach closely resembles a LLZ/DME approach and that is the best way to understand them.
The big, and sometimes fatal, difference is that you do not have GPS distance to the field,
instead you only see the distance to the next waypoint.
As almost all legs are 5 nm long, a quick bit of mental arithmetic will add the leg distances and give you a distance to the missed approach wpt.
VFR GPS addicts need to understand this difference.
A graphical display GPS such as a G 430 is an excellent way to get the big picture of where you are and where you are going in the approach.
Older units such as the G155 TSO dont give you any clues.
In an approach, remember that the "ACT" (Active) annunciator is the OK to continue down to the MDA,
its similar to the ILS GS integrity check at the OM when flying an ILS.
Descending to the MDA without the annunciator displayed is a fail item on the test.
Another possible confusion is the missed approach leg to the "H" (Holding) wpt.
It is normally not auto sequenced and must be selected in the missed approach. (usually pressing the "Go To" button will offer it to you)
This is where the G430 helps you get your head around aspects of the RNAV.
feel free to pm me with an email address for some study info.
(this is not a general offer to everyone as I dont have time or opportunity to respond, av8trflying may elect to forward this info)
Safe flying with the Right Approach.
Research CAAPs, AIP, Jepp etc for other needed info.