737-800 Autopilot switch over from HDGSEL to VORLOC

[davefr]

Let's say I'm approaching an airport and I want to use ILS to guide me in.

 

Am I correct in assuming I hit VORLOC when the ILS is intercepted and comes alive as indicated by the course and glide slope deviation indicators showing up on the Primary Flight Display? It appears that VORLOC turns off HDGSEL and APP turns off ALTHOLD at the appropriate times and guides the plane in.

 

Here's my question. If I jump the gun and turn on VORLOC before the ILS is "alive" the autopilot immediately turns off HDGSEL and the plane makes a violent turn. Can anyone explain what's going on when this happens? What's the autopilot trying to do if VORLOC is enabled before an ILS is intercepted.?

 

P.S. I'm flying using VOR's and ILS. (not GPS)

 

TIA

[il88pp]

Vor-loc makes the plane follow the gps.

Use 'app-hld' only.

 

What plane is this exactly? Is it the default fsx 737-800? Or is it an addon, and if so which one exactly?

[davefr]

Vor-loc makes the plane follow the gps.

Use 'app-hld' only.

 

What plane is this exactly? Is it the default fsx 737-800? Or is it an addon, and if so which one exactly?

 

It's the default 737-800.

 

Why would VOR LOC follow GPS if the selector switch is set to NAV vs GPS?

 

...and what happens when both VOR LOC and HDG SEL are both enabled with the selector switch set to NAV. Which takes precedence in the AP (Heading or VOR)?

 

 

TIA

Edited December 15, 2018 by davefr

[tiger1962]

...and what happens when both VOR LOC and HDG SEL are both enabled with the selector switch set to NAV. Which takes precedence in the AP (Heading or VOR)?

 

In flight, you can't have them both selected at the same time, they cancel each other out.

VOR/LOC in NAV mode will follow the course transmitted by the frequency selected on the NAV1 radio, and in GPS mode it'll follow the course contained in the 'next waypoint' data programmed into the GPS.

[davefr]

In flight, you can't have them both selected at the same time, they cancel each other out.

VOR/LOC in NAV mode will follow the course transmitted by the frequency selected on the NAV1 radio, and in GPS mode it'll follow the course contained in the 'next waypoint' data programmed into the GPS.

 

 

Maybe it's a bug, but I've had them both simultaneously enabled on several occasions.

 

Thanks!