OM u/s

[flyburg]

Hi all,

Tried to do a search on here but to no avail.

Quick question: say you are flying an ILS DME with the DME inop, the inop table says you have to have either DME or a radial or radar etc, or any other means to independently establish the position of the OM.

Is it legal to use FMS/GPS to determine the position, especially if the OM is coded. For example AMS, all points, FAF and OM, are coded with EH waypoints.

In other words, is the FMS updated by GPS a legal way to independently establish a position according to JAR/EASA inop table.

Thanks

[de facto]

I would say yes.

[172_driver]

Although not relevant to Europe, the FAR/AIM has some guidance material on this. Under section 1-1-18, Global Positioning System.

Chapter 1.?Air Navigation (http://www.faa.gov/air_traffic/publications/atpubs/AIM/aim0101.html#ffAks301atcn)

It's not crystal to me either, but I read it as a GPS receiver fulfilling certain Technical Standard Orders, installed by the right guy, approved for use by the right authority, yes.. you can use it in lieu of ADF and DME.

[latetonite]

Yes you can. Are you saying you are flying an FMS aircraft, and for every ILS approach, you tune the NDB?
The combination of ANP and databased waypoints does not require the actual beacon to be identified.

[Intruder]

If the NDB is a required part of the approach, you are legally required to tune it! Not all Marker Beacons are routed through an NDB, though; most go through a dedicated Marker Beacon receiver.

[Denti]

Depends on rules i guess, EU flight ops here but we do not need to tune nor to identify an NDB, the coded FMC waypoint is enough. Still like to do it myself, but that is personal technique and not required anymore.

[JeroenC]

Denti, where can I find that? Are you referring to an approach with funtional DME? To my knowledge for a conventional ILS approach it must all be raw data.

[Piltdown Man]

I reckon that when you can confirm the status and integrity if the GPS (like having a TERM or Approach announciation - or what ever the Fat Albert displays) and have an accuracy of 0.3nm or better then you have met the requirements to determine the position if the OM. After all, you could be in exactly the same place doing an RNAV (GNSS) approach.