What could be the cause of both CMD's refusing to be active at the same time?

[cliffardus 3]

Preparing to land I press the VOR LOC button followed by the APP button and finally both CMD buttons.

 

Sometimes however one of the two CMD buttons switches off. When I press it again the other button switches off. Not always but sometimes.

 

What could be the cause please?

 

Cliff

[maple-syrup 40]

Are both of the ILS freq tuned to be the same? Is the APP actually engaged? Or just high lighted... 

[cliffardus 3]

The frequency on both are identical.

 

How do I check whether an unlighted APP is actually engaged?

 

Cliff

[rsvit 16]

quote name="cliffardus" post="2720940" timestamp="1374464281"]How do I check whether an unlighted APP is actually engaged?

 

Check that LOC and G/S are green on FMA (that's above attitude indicator).

[tcas_climb 45]

both courses must also be set to the same.

[Spin737 102]

What altitude are you (AGL)?

[cliffardus 3]

I think the "problem" is solved and I'm grateful to you all for trying to help.

 

Regards............Cliff

[Chrjs 61]

I think the "problem" is solved and I'm grateful to you all for trying to help.

 

Regards............Cliff

Could you please tell us what solved the "problem" - otherwise the next user with the same "problem" has still no answer....

[cliffardus 3]

Mea culpa.....it was my fault entirely as I'd entered the wrong ILS frequency for the destination airport. As simple as that...

 

I'm so sorry for wasting your time.

 

Cliff

[Chrjs 61]

Mea culpa.....it was my fault entirely as I'd entered the wrong ILS frequency for the destination airport. As simple as that...

 

I'm so sorry for wasting your time.

 

Cliff

You haven't - happens to all of us, good to know you got it sorted out! Have fun.