Adding a 40 mile fix from arrival airport as a waypoint

[Ray Proudfoot]

I always fly with Radar Contact rather than online. One of the requirement of RC is to be at a certain altitude 40 miles from the destination airport.

It's not always easy to determine this distance and add a lat/lon fix with a altitude restriction so I'm wondering if a feature in the CDU can help. If I press FIX and enter the ICAO of the arrival airport and then enter /40 in the next LSK a circle is drawn around that airport.

Is it possible to add a waypoint to the CDU that lies at the intersection of the 40 mile circle and my current heading? I've heard it may be possible but can't work out how to enter one.

Thanks.

[Peter Dowson]

Is it possible to add a waypoint to the CDU that lies at the intersection of the 40 mile circle and my current heading? I've heard it may be possible but can't work out how to enter one.

According to the Bill Bulfer guide (don't you have one, I thought I gave you my old one?), on the FIX page, once you've done what you said and got the circle drawn, you should be able to place the fix in the scratchpad (the bottom line) by clicking on the FIX line's LSK (probably LSK2) -- it'll look something like XXXXnnn/40 where XXXX is the fix (destination airport?), nnn is the radial to your route intersection, and of course 40 is your radius.

Then go to the legs page and insert it in the normal way. The name should change to XXXnn (XXX being a possibly abbreviated fix name, and nn being 01 for the first temporary fix based on it, 02 for the second, and so on.

In Bulfer it is called "Distance Entry -- In route" and is explained in the FIX section (page 146 in my copy).

Now that might be what we tried in PM's CDU when you were here. I don't remember. It should work -- if it doesn't, please do write to PM Support and ask them to add it! ;-)

Best Regards

Pete

[Ray Proudfoot]

Hi Pete,

Yes, I have the Bulfer Guide but I can't find anything that would do what we want. There's no entry in the Index for 'FIX' and looking at the user-defined waypoints none cover the requirement. I remember what we tried a couple of weeks ago and tried that but to no avail. It seems the standard CDU cannot use airport IDs as a fix.

It looks like a request to Enrico is the only way to get this implemented. I'll drop him a line and hopefully if he's not too busy he can do something for us.

[767300]

Hi Ray,

Perhaps select a VOR at the airport into the fix using Petes method above. I use the PBD(Place Bearing Distance) from Bill Bulfers guide. Page 19 on mine.

Regards

James

[Peter Dowson]

Yes, I have the Bulfer Guide but I can't find anything that would do what we want. There's no entry in the Index for 'FIX'

Correct. none in my "Index" either. But FIX is actually a button on the FMC and a complete facility, meriting and described in a whole chapter in Bulfer -- it appears in the Contents, not the Index, as "FIX INFO". If you can't find it in the Contents either, then I can only think you are looking in the wrong book. it's the Bulfer book for the FMC, not the 737 Cockpit companion.

Note that every page in the FIX INFO chapter has FIX INFO printed in bold at the top, so if you can't find the Contents you can at leasdt scan the tops of the pages -- its all about half way through, maybe a little more.

In the chapter called "FIX INFO" its on the second page in my copy -- entitled, as I said "DISTANCE ENTRY - IN ROUTE".


... and looking at the user-defined waypoints none cover the requirement. I remember what we tried a couple of weeks ago and tried that but to no avail. It seems the standard CDU cannot use airport IDs as a fix.

But it draws the circle, so it must be able to.

I tried again today. It did produce a fix, and I could transfer it to the plan -- but it was 2,900 nm away!

I think that's what happened when we tried it last time. Lookslike a bug in PM's MCP, it is probably getting Lat/Lon at 0, 0.


It looks like a request to Enrico is the only way to get this implemented. I'll drop him a line and hopefully if he's not too busy he can do something for us.

It appears to be an outright BUG rather than omission. I'll write to him too.

Pete

[Ray Proudfoot]

Hi Pete,

Thanks for confirming it seems to be placing the intersection at Lat 0, Lon 0. When I tried it it did put an entry in the Legs page but I didn't suss out it pointed to 0/0.

Hi James,

That system is fine where there is a VOR on the field but quite often there isn't. It seems the airport fix should work but is broken. Hopefully Enrico can fix it soon.

[Peter Dowson]

That system is fine where there is a VOR on the field but quite often there isn't. It seems the airport fix should work but is broken.

So are you saying the exact same process works for a VOR but not an airport? I've not tried it, but it seems odd that there's a difference in the PM CDU like that -- after all it must reference the airport's position to do the circle, just as it does the VOR.

Pete

[Ray Proudfoot]

So are you saying the exact same process works for a VOR but not an airport? I've not tried it, but it seems odd that there's a difference in the PM CDU like that -- after all it must reference the airport's position to do the circle, just as it does the VOR.

Pete

No, I'm doing what programmers should never do - assume. ;) I'll try it over the weekend but you might beat me to it.

[JWS]

Ray,

any news on this (or has it been fixed already)?

JWS

[Peter Dowson]

any news on this (or has it been fixed already)?

Enrico fixed it straight away. It's okay in all the recent releases from PM.

Regards
Pete

[JWS]

Thanks, Pete.

Best regards,
JWS