Meaning of Roger?!

[Auxtank]

Originally Posted by double_barrel

Preparing for comms exam, I see some oddities in terminology, can I check back with you folks on these?

Roger - the book says this means all received OK but (I deduce) does not imply all understood. Is that correct? I had previously believed that Roger conveyed received and understood. I could imagine circumstances in which a message is received clearly but the pilot does not understand the meaning or is unable to comply. It would seem very odd to acknowledge with Roger under those circumstances?

Mayday procedures. An oddity of the aviation mayday procedure is that you identify the called station as the next element after the mayday x3. That seems wasteful of time when you are calling on whatever freq you happen to be on anyway. Am I reading that right? In the marine world a mayday call implies a call to 'all stations' and you would not specify the called station.

Thanks! No doubt more to come

What's the difference between "Understood" and "Roger"?
Understood is used to acknowledge information while no need to act while Roger is used to acknowledge some information or an instruction after which the acknowledger will 'act'.

With Mayday procs I do think it's a waste of time to address a particular station and certainly in the maritime world it is as you say; it's a call to ALL stations.

"MAYDAY MAYDAY MADAY. This is sailing vessel "Whatever" MAYDAY MAYDAY MAYDAY.
Give POS, nature of distress, number of SOB and immediate intentions (abandoning ship, etc)

But if if it's the CAP then you've got to do it correctly for the exam.

As in: CAP 413

Emergency Message

8.13

The emergency message shall contain the following information (time and circumstance permitting) and, whenever possible, should be passed in the order given:

1. ‘MAYDAY/MAYDAY/MAYDAY’ (or ‘PAN PAN/PAN PAN/PAN PAN’);
2. Name of the station addressed (when appropriate and time and circumstances permitting);
3. Callsign;
4. Type of aircraft;
5. Nature of the emergency;
6. Intention of the person-in-command;
7. Present or last known position, flight level/altitude and heading;
8. Pilot qualifications (See Note 1), viz:
   1. a) Student pilots (see Notes 2 and 3);
   2. b) No Instrument Qualification;
   3. c) IMC Rating;
   4. d) Full Instrument Rating.
9. Any other useful information e.g. endurance remaining, number of people on board (POB), aircraft colour/markings, any survival aids.