Having doubts about your radar? You need a confidence check! The Honeywell procedure given below is for the Primus 660, an earlier version than what is on the G450. But it works for the Primus 880 too.
Everything here is from the references shown below, with a few comments in an alternate color.
Figure: Radar confidence check, from Honeywell Radar Training, Part 7, Slide 36.
Figure: Radar confidence check, from Honeywell Radar Training, Part 7, Slide 37.
Since this radar paints ground to 150 nm and the charts says 115 nm is the minimum, it passes the check.
It has been my experience that nobody at Boeing, Bombardier, or Gulfstream understands radar and what to do if it isn't working:
There, I got that off my chest. But there are two lessons here. First, when dealing with radar problems, don't forget to check with those who built the thing in the first place. Second, in the case of the G450, you have resources available to you that many in Tech Ops seem to have forgotten:
Gulfstream G450 Maintenance Manual, Revision 18, Dec 12, 2013
Honeywell Airborne Weather Radar Training, Rev E, 12/09/02, Honeywell Inc. Commercial Flight Systems Group, Phoenix, AZ.
Honeywell Primus 880 Pilot's Guide, Pub. No. A28-1146-102-03, Revised January 2006, Honeywell International Inc. Commercial Electronic Systems, Glendale, AZ.
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