What is the "non-apologizing rule"?

Question

I was reading some forum about funny ATC communications and one commentary was

GXXXX: Request status of danger areas X1, 2 and 4
<Pause>
London info: I don't recognise area number x124
GXXXX: My mistake I meant areas x1, x2 and X4
London info (female): Sorry, just had a blonde moment here

(assume she was new and didn't know the non appologising [sic] rule)

(source)

when referring to some thing the ATC said, apologising for not understanding some non-formal phraseology.

What is that rule ?

Answer 1

I suspect there is no such rule. I looked at a few online sources - none mention the word apology (or variants).

ATC communication is expected to be short and follow a standard set of stock phrase forms.

Anything outside that is discouraged unless necessary to clarify instructions etc.

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FAA

An FAA document "Radio Communications Phraseology and Techniques" says

Brevity is important, and contacts should be kept as brief as possible,

So any communication that doesn't follow one of the standard patterns is discouraged. It continues.

but controllers must know what you want to do before they can properly carry out their control duties. And you, the pilot, must know exactly what the controller wants you to do. Since concise phraseology may not always be adequate, use whatever words are necessary to get your message across.

ICAO

An ICAO document "ICAO Standard Phraseology A Quick Reference Guide for Commercial Air Transport Pilots" says

Phraseology has evolved over time and has been carefully developed to provide maximum clarity and brevity in communications while ensuring that phrases are unambiguous.

Again the emphasis is on brevity and standard phraseology. It also continues ina similar way to the FAA document.

However, while standard phraseology is available to cover most routine situations, not every conceivable scenario will be catered for and RTF users should be prepared to use plain language when necessary following the principle of keeping phrases clear and concise.

Other

For non-pilot rubberneckers like me, a good intro to pilot-ATC communication is a "Say Again" blog post or Two by Don Brown.

I remember one time when I was a young controller and working a slow, high-altitude sector. I was bored so I got into a conversation with a pilot about something or other. All of a sudden I noticed this F-15 was in a big turn.

 "Peach two one, Atlanta Center, where you goin'?"  
 "Atlanta Center, Peach two one is declaring an emergency, 
        we've lost an engine and are returning to Dobbins."  

He couldn't get on the frequency because I was having a conversation.

Answer 2

As far as I know, this is not an official rule, but I have heard about it in the past.

I think the 'rule' has its background in two principles:

Firstly, you keep communications efficient and short. Don't block the frequency unnecessary. Some countries have guidance in their ATC communication handbooks that discourage exchange of courtesies. Apologizing could be categorized as such. For example: in the UK CAA has the following text in their CAP 413 Radiotelephony manual:

Avoid excessive use of courtesies and entering into non-operational conversations

Secondly, you don't apologise for asking clarification on the frequency. It implies that you made a mistake. Making sure that the communication is clearly understood by both sides is an essential safety requirement and therefore asking clarification should never be apologised for because it is the only right thing to do when in doubt.

In the context of the eternal pissing contest between pilots and controllers the above is sometimes reduced to following rules:

1. Never apologize on the frequency
2. Never call a pilot 'Sir'

It will make THEM feel superior.