ATC page doesn't offer me the correct response...

[Will]

Air traffic control, via CPDLC, asked me to report crossing a particular intersection. On the ATC page of the FMC, I was given the option to respond ROGER, but correct telephony would be to respond with WILCO. Can this be an option?

Thanks.

[Hardy Heinlin]

In Boeing's FANS it's Roger, if I recall correctly (FANS CBT or photo on the real deck).

Or are you asking for an option in PSX?

[Will]

Not to say things everyone already knows... but ROGER means "I have received and understood your transmission" while "WILCO" means "I will comply with your instruction."

So you say ROGER when ATC passes along factual information ("You can expect FL390 in 15 miles"), but you say WILCO when ATC gives you an order ("Report crossing XXYYZ").

I don't know what the real FMC would do here, but the correct response would be to say WILCO. PSX models this correctly when ATC gives other commands.

[Hardy Heinlin]

Looks like all Report commands set the ROGER word, and all other commands set the WILCO word.

I can't remember my exact source for this, but maybe they set ROGER for all commands that won't affect the aircraft status, i.e. pure "tell me" stuff, not "fly this way" stuff.

[Will]

On almost all of the others commands: cruise climb, route offsets, airspeed restrictions, etc... for ATC commands, the response options in PSX are usually either WILCO or REJECT. (This is correct.)

[Jeroen Hoppenbrouwers]

These things are regulated. I will look for the official list. May take a while and if I forget, please remind me.

There is a distinct possibility that I was Hardy's original source, in the form of a config file for my old CPDLC module for the ACARS network, and there is a good chance that I at that moment (before I really got into this professionally) did not have proper documentation at hand.


Hoppie

[Hardy Heinlin]

There is a distinct possibility that I was Hardy's original source, in the form of a config file ...

That's rather unlikely. Almost everything in my model is based on what I saw on a FANS-1 CBT. There are also some later PSX modifications based on real world observations and some public CPDLC references.

[Jeroen Hoppenbrouwers]

From DO-258A:

W/U = Wilco or Unable
A/N = Affirmative or Negative
R = Roger
NE = means neither of Wilco, Unable, Affirm, Negative, Roger, or Standby. So probably they mean No Response.

For the REPORT uplinks, the table shows "R" for the following:

127 Report back on route
128 Report leaving [altitude]
129 Report level [altitude]
130 Report passing [position]
175 Report reaching [altitude]
180 Report reaching block [altitude] to [altitude]

All others, including all CONFIRM uplinks, are "NE".

[Hardy Heinlin]

So it's correct in PSX.

I think it makes sense to use Wilco just for the "fly this way" stuff, not for the "tell me" stuff. The opposite of "Wilco" is "Unable", and "Unable" is a performance or weather thing, not a "tell me" thing.

ATC: "Report present position."
Pilot: "Unable."
ATC: "Why?"
Pilot: "I forgot."