[Ahem… they promise THIS month… :-)]
I decided to take Derek’s GNS430 simulator test (see earlier messages from him) to dust
off my quickly fading 430 skills and after doing most of the excercises on his list, I remembered a real-life problem that both Dave Katz and I have experienced on several occasions.
Flying from Wattsonville to San Jose, one usually takes an “L” shaped course to avoid some high mountains immediately north of WVI on the direct course. Often we are given a radar-vector south-east, followed by “join the Salinas (SNS) 347 radial, resume own navigation” (which would send us to GILRO, but they often vector us NW before we get to GILRO) to short-cut going all the way down to Salinas.
The common “proper” answer to doing this in the GNS430 is to figure out why you were given the radial, and just plug in the destination waypoint instead. Other folks just tune in the VOR and do it the old fashioned way.
In this particular case, if I were to proceed direct to the next WPT (GILRO), it would be a significantly different course than the join.
I want to fly my current track, intercept a radial several miles from the VOR, join it, and track outbound to a distant waypoint.
What’s the “proper” way to do this without relying on the VOR?
I end up flying the radial - L quite frequently in crowded NY Class B and have adopted the Keep It Simple approach for two reasons:
the exact clearance always changes in the air
there is little / no time available to work sophisticated solutions with the GPS. Besides, I should be looking out the window.
So, here is the scenario I fly, for what it is worth. Two cases:
- Departing KTEB. Vectors for departure to COL VOR.
a. Set flightplan KTEB - COL …
b. After several 360’s to climb above KEWR approach / departure traffic, usually get FLY HEADING x (let say 260 this time) to intercept COL RADIAL 350 INBOUND.
c. Heading (and BUG) to 260. Usually with AP HEADING mode to give me more eyes outside time. GPS will continue to show direct course heading to COL.
d. After established 260 and looking out the window to avoid the heavy metal all around, set the GPS to OBS via HSI to 170 (350 inbound). Takes about 1 second. Leave the AP on HEADING.
e. MAP now displays 350 radial inbound to COL. AP continues to fly 260. Monitor CDI or GPS version for distance to intercept. At roughly 1 mile from intercept, turn inbound to intercept radial (or just press NAV on the AP and let it do the intercept.
- If there really was a VOR instead of HEADING clearance, I’d modify the above only slightly. Lets assume its inbound to TEB then TEB 260 radial to intercept COL 350 radial. If you REALLY know the clearance ahead of time, set up the user defined waypoint per other posts this message. But if its on the fly in crowded airspace, I’d
a. Flight pllan already shows TEB - COL. Inbound to TEB would go to OBS 5 miles out. OBS to inbound course TEB. Then, about 1 mile out from TEB OBS to 260 (still TEB since waypoint will not sequence in OBS mode). If on AP, it would intercept the outbound radial. GPS waypoint holds at TEB.
b. Once established 260 outbound, set HEADING BUG to match outbound heading (now will correct for cross wind). AP to heading mode. No longer strictly tracking radial, but since already oncourse, with wind correction made and a likely short leg, this matters a lot less than having time to look outside.
c. OBS off. GPS will sequence to COL. But AP will continue to fly the HEADING BUG. Reset OBS 170. MAP now displays 350 radial inbound to COL. Monitor CDI or GPS version of CDI for distance to intercept. At roughly 1 mile from intercept, turn inbound to intercept radial (or just press NAV on the AP and let it do the intercept.
Again, its quick, its pretty much the same with either a heading or radial outbound clearance. Lots of time to look out the window.
Hope the above “low tech” solution is useful.