'Set OBS and hold' question

[Emmanuel]

Hello,

Again a question with the G695.
I'm trying to acquire some habits (with the simulator) to manage emergency flight diversions, due to bad weather ahead, ATC orders, or unexpected events.

I thought that the 'set OBS and hold' could be useful when I fly on a certain heading, and for some reason I have to change and fly to another heading.
So I imagined that the 'set OBS and hold' would show my new heading regardless of my navigation.

But apparently, it's not. The GPS shows the user select heading FROM my next WPT. I don't really understand why, and the G695's manual is not that explicit with this function.

Can someone explain (slowly please ) what is the purpose of this function.

Thank you in advance and sorry for my english


Emmanuel

 

[W. Stewart]

Before I had a panel-mount GPS, when I relied on ADF to get me into my home airport, I used a Garmin 295 for situational awareness. I would use the "Set OBS and Hold" function throughout the procedure turn (or holding, in the case of a missed approach). You can look at the NDB 25 approach to KZEF (Elkin NC) to follow along, if you like. The course from the NDB to the runway is 242. "Set OBS and Hold" draws a magenta line from the waypoint (in this case the ZEF NDB beacon) on whatever course you dial in. So, one can dial in 242. Then one can use the device to get rather precise orientation relative to that course. Fly to the NDB, fly outbound on 062 and do your procedure turn, fly inbound on the 242, etc.

One could also use the feature to join a specific radial from a VOR. Dial in the desired course from the VOR station and use the CDI representation to orient yourself relative to the desired radial. The split screen will show the HSI with CDI, and the moving map will show the magenta line. (Of course, one can also do all this with just a NAV radio, only without the pretty magenta line!).

Wells

 

[Areeda]

Wells got it.

I think from your post that the point of confusion is that the obs is the bearing from/to the next waypoint not from your current position.

Joe

 

[Emmanuel]

Hi Joe and Wells,

thank you for your anwsers.

Wells, thanks for your explanation, but Joe's right. I'm confused with the OBS set to the next WPT instead of my current position.
But I have to figure how to use it in an awareness situation (if it can be one of its purpose).
I trained it few minutes ago after I read your post to set an OBS on my airport approach in case of a go-around, and I see now the use I can get from this function, even if it's not exactly what I figured.

I have simulated ATC diversions to some points (whatever they can be, VORS, NDB, airports, or cities) with the NRST button to interrupt my nav, and then resume it later. That works very well, and that really a good point.

Thanks your your answers again, best regards

Emmanuel