The same in Australia and I find it quite annoying. There is no mention of 'guard' in Aus yet the term is used on-air quite a lot.
I refuse to recognise its use and always use/say 121.5.

Given the number of people crossing swords on this subject, one could be forgiven for believing it's from the French - "En Garde!". :p

In The UK
 

..............and I may be / am wrong.......
There was many moons ago about the late 80's/early 90's, as published in the supliments, the phrase 'All stations this frequency, stop transmitting X3, MAYDAY in progress' I believed this to be related to 121.5. Such call could be made by any ground or air station privy? Have I remembered right?

That would kill the practice pan, all chatter, though there seemed none then, yet being a costal Ops guy I monitored 121.5 on the GTA on scan.

And of course 'grammer' is spelled 'grammar'. Let's not go there.

Maybe D&D should have a QSL card designed, so every time they unequivocally identify one of the offenders, they can print and send one with only a few keystrokes.....

I was given to understand that 243 was the Emergency Frequency however, because of various technical factors involving prorogation of radio waves and carriage of UHF, a VHF frequency was provided as a back up or 'guard' for the main [243]. I also remember somewhere in the distant past to the D&D cell one of the senior people there stating that it was preferable for a crew to initiate a practise Pan because it offered a way for a crew who were on the verge of a real Pan situation to avoid it. I don't know it that thought is still there.

Best Wishes

I AM stupid..... should have seen this ages ago.

Of course 243.0 is exactly two times 121.5 !
Any technical reason that anybody knows of, like running off the same crystal?

If one wanted to be pedantic, 243MHz isn't UHF, because 'formally' UHF doesn't start until 300MHz. But the answer is of course simply, that in aviation "118-137" is VHF and "225-400" is UHF.

Inter-pilot air-to-air freq 123.45; and the use of he word "Guard"
 

For those PPRuNers wondering where the inter-pilot air-air freq 123.45 has its authority in aviation regulations, please check out the following references in Jepp World Wide Text. (Following 123.45 is the use of the word "Guard".)

A. 123.45

Jepp WWT ATC Pacific Page 9-10

7.1 GENERAL PROCEDURES
.....
c. establish communications with and alert nearby aircraft by broadcasting, at suitable intervals: aircraft identification, flight level, position (including the ATS route designator or the track code, as appropriate) and intentions on the frequency in use and on 121.5 MHz (or, as a back-up, on the inter-pilot air-to-air frequency 123.45 MHz);

7.2 WEATHER DEVIATION PROCEDURES
General
….
b. establish communications with and alert nearby aircraft by broadcasting, at suitable intervals: aircraft identification, flight level, position (including ATS route designator or the track code) and intentions, on the frequency in use and on 121.5 MHz (or, as a back-up, on the inter-pilot air-to-air frequency 123.45 MHz);

7.3 PROCEDURES FOR STRATEGIC LATERAL OFFSETS IN OCEANIC
AND REMOTE CONTINENTAL AIRSPACE


….
NOTE 1: Pilots may contact other aircraft on the inter-pilot air-to-air frequency 123.45 MHz to coordinate offsets.

8.1 CONTINGENCY SCENARIOS (Pages 11-14)

If considered necessary, alert nearby aircraft by (a) making maximum use of exterior lights; (b) broadcasting position, FL, and intentions on 121.5 MHz (as a backup, the VHF inter-pilot air-to-air frequency, 123.45 MHz, may be used).

So as you can readily see, 123.45 is a legal ICAO inter-pilot air-to-air frequency. The UK, USA, EU an most developed countries are all signatories to the ICAO Aircraft Operations regulations which includes PANS-OPS, I believe.
~~~~~~~

B. Use of the word ‘Guard’. It is correct to state that the VHF freq 121.5 is called an Emergency or Distress frequency in the regulations. (see below)

Jepp WWT EMERGENCY Page 1

INTERNATIONAL CIVIL AVIATION ORGANIZATION (ICAO) Extracted from the following ICAO publications:

RULES OF THE AIR, ANNEX 2

2.3 DISTRESS FREQUENCIES
2.3.1 …. there is a need for designating a particular frequency or frequencies to be used in order that uniformity may be attained on a world-wide basis, and so that a guard may be maintained or set up by as many stations as possible including direction-finding stations, ….....
2.3.5 With respect to survival craft stations the following emergency / distress frequencies are provided:
a. VHF — 121.5 MHz;
b. UHF — 243.0 MHz;
c. HF — 500 kHz, 2182 kHz, 8364 kHz.
...

Jepp WWT EMERGENCY Page 3-4

5.2 RADIOTELEPHONY DISTRESS COMMUNICATIONS
....
1. The foregoing provisions may be supplemented by the following measures;
a. the distress message of an aircraft in distress being made on the emergency frequency
121.5 MHz or another aeronautical mobile frequency, if considered necessary or desirable. Not all aeronautical stations maintain a continuous guard on the emergency frequency

From the above references in the Jepp WWT ICAO regulations, the word ‘guard’ is used mainly to describe the actions of aviators and ground stations in listening out or ‘guarding’ Emergency frequencies for distress calls. Over the years, the emergency frequencies themselves have simply been referred to as ‘Guard Frequency’, because that is what you do; ‘guard’ the frequency.

I hope this answers the questions posed with regard to the 123.45 inter-pilot air-to-air frequency and the use of the word ‘guard’ when referring to the emergency frequencies 121.5 and 243.0. Cheers.

Fantastic post, thank you. Probably won't end the b******t though on here, they have nothing better to do than guard the thread.:ok:

Magnet77 : Join Date: Jul 2008 - Posts: 1
Inter-pilot air-to-air freq 123.45; and the use of he word "Guard"

What a remarkable first post from a 'newcomer'.

Many thanks, Madam or Sir, and my sincerest respects!
Welcome!

Just one small point, the text quoted appears to have been lifted from a regional procedure (albeit the Pacific!!) with links to Annex 10. From Annex 10 Vol II:

5.2.2.1.1.1
Aircraft on long over-water flights, or on flights over designated areas over which the carriage of an emergency locator transmitter (ELT) is required, shall continuously guard the VHF emergency frequency 121.5 MHz, except for those periods when aircraft are carrying out communications on other VHF channels or when airborne equipment limitations or cockpit duties do not permit simultaneous guarding of two channels.

5.2.2.1.1.2
Aircraft shall continuously guard the VHF emergency frequency 121.5 MHz in areas or over routes where the possibility of interception of aircraft or other hazardous situations exist, and a requirement has been established by the appropriate authority.

5.2.2.1.1.3
Aircraft on flights other than those specified in 5.2.2.1.1.1 and 5.2.2.1.1.2 should guard the emergency frequency 121.5 MHz to the extent possible.

5.2.2.1.1.4
The user of the air-to-air VHF communications channel shall ensure that adequate watch is maintained on designated ATS frequencies, the frequency of the aeronautical emergency channel, and any other mandatory watch frequencies.

5.2.2.1.2
Aeronautical stations shall maintain watch as required by the appropriate Authority.

5.2.2.1.3
Aeronautical stations shall maintain a continuous listening watch on VHF emergency channel 121.5 MHz during the hours of service of the units at which it is installed.


An interesting use of the word guard. Aircraft are required to guard 121.5 whereas ground stations shall 'maintain a continuous listening watch'. I wonder what ICAO perceive as the difference between the two phrases?

Guard Police Wrong - Official
 

From the latest GASIL:
Unauthorised radio transmissions?
Having written the previous
two articles, we became aware of
some unauthorised transmissions
recently heard, on two apparently
separate occasions, on the
emergency frequency 121.5MHz.
However, these seemingly came
from an aircraft!
On both occasions, it seems
that the Distress and Diversion
cell were providing assistance to
inexperienced pilots who had
found themselves in worse
weather than they expected.
While that assistance was being
given, it is reported that a series
of transmissions were made by
people who were apparently pilots
(possibly holding licences issued
outside the UK) suggesting that
the radio exchanges providing
that assistance were interfering
with their own operations.
It is standard procedure
(indeed a requirement) for
airliner crews to listen out on
121.5MHz in addition to their
own operating frequency while
cruising. Some of these crews
may consider that their
convenience is more important
than the necessary training calls
(Practice Pan), or as in this case
even the provision of essential
safety assistance. They are
wrong.The UK Distress and Diversion
service provides direct
assistance to pilots in a manner
unique in the world. Those who
have never experienced the
service, nor learnt about it
during their training, may feel
the frequency is being misused.
However it is not up to them to
attempt to make unauthorised
transmissions. They have the
facility to submit reports if they
are concerned about what they
believe might be a possible
misuse of the frequency.Apparently the interfering
transmissions in at least one of
the reported instances were so
frequent and so aggressive that
the inexperienced pilot found
themselves concentrating more
on the accusations than their
flying. Ladies and gentlemen,[if
you need assistance, you are not
only entitled but encouraged to
ask for it on 121.5MHz, and if
you are subjected to such
unauthorised transmissions
ignore them as much as you can,
Do take note and report them,because it is possible they may
not be received by the D & D
ground stations.

For those of you who may be unaware, GASIL is the official publication of the CAA SRG.

Mods, please would you be kind enough to leave this here for the real culprits to see? If you wish to lock it so that it is "read only" that's fine but it needs to be read by the small number of highly unprofessional people bringing commercial aviation into disrepute and putting people's lives at risk.

Being a lowly GA pilot, I generally flick between a local ATIS and 121.5 on box 2. I've reported 2 (CAT) aircraft this year for frankly outrageous abuse of the D&D frequency. Casual, unneccessary, sarcastic transmissions on an emergency frequency are not big, nor are they clever. I have no idea whether any action was taken as a result of my reports. I would like to hope so, yet I cynically suspect not.

Flying in command of a large jet does not immunise you from being a complete d1ckhead with your head up your arse when you press the transmit button and revert to schoolboy mode.

:ok:

DX Wombat,

Superb response. As a (as Shunter puts it) lowly GA pilot, but also an ATCO, it never ceases to amaze me how quickly any transmission on 121.5 is met by cries of "you're on guard!!!!" as if the frequency should remain sterile at all times. Said responses often eminate from CAA licence holders as well.

Heard the classic the other day, some poor sod accidentally called xxx ops on 121.5 (we have all done it) then some smart arse replies "you are on guard" which was obviously misheard as "go ahead" and then this guy unfortunately gives his ETA at XXX etc.

Just wish the guard police would give it a rest!!!

something to try out . . . . . . . . ! !
 

This thread has been a complete eye opener to me ! Had PPL for 27 years, but never heard of this before !

Next times I go flying I'll certainly be listening out on 121.5 on box 2, so I wonder whom I'll hear ? !

"so I wonder whom I'll hear"

Well AMEandPPL, you will most probably hear some retard calling their company or worse still doing a PA/talking to cabin crew, followed by about 5 yanks saying "your on Guard". This is why, I am sorry to say, a lot of airline pilots no longer monitor 121.5, it's a complete waste of time.

You will seldom hear any genuine practice pans/emergencies because they will be blocked out by the guard police who are at higher altitudes and therefore have stronger transmissions.

BS !

Guard is still monitored in my company by 90 % of all pilots.
Used guard this morning to find a company a/c that vanished from london ATC. No problem, only a short call, problem fixed.
Guard still has a useful function IMHO !

OK guys I admit I have not read all the posts on this thread, but in the UK practice "Pans" are encouraged for training purposes and you have to do it on 121.5 or 243 cos they are the only frequencies D&D have with Auto-Triangulation. Nuff said!

121.5...a complete waste of time, with all the UK prats calling for practise PANS at all hours.
A pox on these folks.:yuk:

411A is right about 121.5
 

90% of time !?
How much of % do you contribute to Guard Police ?

411A is right. Switch it off unless you really need it. Like no more contact on active fq after a suspicious silence.