Mike Adams wrote:


The 430/530 didn't provide hold guidance prior to the upgrade. The point he was trying to make is that
this feature is part of the same upgrade package, but not specifically related to WAAS. As Sam said, the
big-boy FMSs have provided hold and procedure turn guidance for years, using just VOR/DME or
DME/DME position updating.

So far as I know, although a lot of them used (and still do with the
older birds) DME/DME updating, none of them used VOR/DME updating...well
unless that was all that the system could see...and often it would just
stay with IRU position rather than use a bad solution.

Having said that, the method of flying track-guidance around a holding
pattern does not assure containment (at least in a jet at max holding
speed) unless the FAA holding patterns rules are followed (or the ICAO
rules).

Perhaps Garmin has been smarter than the big guys (they often are).