B737 NG set up for ILS with non co-located DME

[Otto Throttle]

I'm curious as to how the nav systems can be set up in order to fly an ILS approach, where the DME is provided from a non co-located VOR?

Company SOPs mandate that both pilots hav the ILS tuned and identified for the approach, but I can't see a way of ensuring that the DME from the associated VIR station can also be monitored as there is no DME hold function.

The only solution I can currently think of, is for PM to have the VOR/DME tuned initially in order to cross check correct glide path indications crossing the FAP, and then tune the ILS.

All suggestions welcome from someone who is feeling a bit stupid.

[de facto]

Have a look at Stuttgart (EDDS) ILS 25.(DME required)
You will see the DME is from a VOR,not the localizer,and yet Cat 2/3 can be flown.
How would you set up your Autoloand?

[Xiamen]

It's not a stupid question. I have done this a few times, and I used ILS on my side, and VOR on the other, and switched both to ILS after I got a alt/DME check.
The other way to do this is to use FIX page for the DME station.

[Denti]

Set the fix page to the VOR/DME and make sure that your ANP is low enough.

[FlyingStone]

Sadly, Boeing never took the 757/767 design of ILS tuning to 737, so you have only two receivers available for manual tuning.

With NG, you should have GPS and thus you can more or less consider zero map shift, so both FIX page and ND should be very accurate, so together with VNAV deviaton indication you should have a very good idea whether you are capturing the correct glideslope or not.

[ImbracableCrunk]

You have an approach like an ILS DME and you can't simply identify the fixes vai the GPS/FMC?

[Otto Throttle]

Thank you for the feedback.

I didn't think it was possible to monitor the DME from a non co-located navaid, but it's always worth checking.

The use of the FIX page helps, but doesn't necessarily fulfil the requirement of monitoring (from a nitpicking point of view - as lawyers and TREs are prone to do 😉), but combined with an ident prior to both pilots tuning the ILS, and monitoring of ANP, is probably as good as we can get on the super tractor. :ok: