On Thu, 21 Dec 2006 08:41:10 -0600, "Stan Prevost"
wrote:


"Sam Spade" wrote in message
...
Roger wrote:


And here I always though they were VOR offsets. Although I have to
admit it's been well over 10 years since I actually heard any one give
an RNAV off set. :-))
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Offsets are a feature in TSO 145/146 (WAAS capable) sets. The smart money
will use a slight offset to fly a Victor Airway to greatly reduce the
opposite direction mid-air potential. Minor offsets are already approved
on the North Atlantic.

Offsets should not be used for instrument approach or departure
procedures.

I thought Roger was talking about radial/DME offsets like used in KNS80 and
other RNAV boxes to define RNAV waypoints.

He we-)) As in LAN 27015 (I think that was the way they were
worded) Actually I filed an RNAV offset coming out of OSH a few years
ago when MTW VOR was out of service. I used an offset from GRB that
was very close to MTW. The clearance sounded something like OSH
direct GRB17025 Direct LDM, Direct 3BS(I don't remember the numbers
now but that conveys the general idea)



But course offsets were a feature of my old Northstar M3 IFR GPS. Not
mandated by TSO back then, though. I noticed the course offsets in the
GNS430W while reading the manual and wondered why they appeared.

Hard to imagine the FAA mandating course offsets to avoid center-of-airway
conflicts, given the following:

§ 91.181 Course to be flown.
Unless otherwise authorized by ATC, no person may operate an aircraft within
controlled airspace under IFR except as follows:

(a) On a Federal airway, along the centerline of that airway.

(b) On any other route, along the direct course between the navigational
aids or fixes defining that route. However, this section does not prohibit
maneuvering the aircraft to pass well clear of other air traffic or the
maneuvering of the aircraft in VFR conditions to clear the intended flight
path both before and during climb or descent.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com