121.5 mhz

[nexus]

Has the role of the National emergency frequency 121.5 changed in the last few years?

Back when I was in Civil Air Patrol - Mississippi Wing 121.5 was used exclusively on ELT's and EPIRBS and monitored with SAR Satellites by the AFRCC. And the only form of communication allowed on that frequency was the ELT/EPIRB signal.

A couple of weekends ago I programmed 121.5 into my FT-8900 and picked up voice communications on the frequency. This kind of took me by surprise because it was a violation to transmit voice on there during my time in CAP. I'm wondering if anyone has any recent information involving the usage on 121.5 in 2005.

Are there any other CAP members on here who can provide info?

Acronymns defined:
ELT = Emergency Locator Transmitter (device on aircraft which transmit a signal on 121.5 in case of crash used in conjunction with radio direction finding)

EPIRB = Emergency Position-Indicating Radio Beacon. A radio beacon, carried by boats and ships, that is designed to float and transmit a radio distress signal. Most EPIRBS now operate on 406.0250 mHz

SARSAT = Search And Rescue Satellite Aided Tracking A constellation of low– and high–earth orbit satellites that listen for radio distress signals on 121.5, 243.0, and 406.025 MHz from ELTs, PLBs, and EPIRBs. System allows rapid triangulation to calculate position of beacon to within several kilometres (usually).

AFRCC = Air Force Rescue Coordination Center. Once located at Scott AFB, IL. Now it's located at Langley AFB, VA.

 

[nexus]

Actually one thing I have found in some research which might be of interest to anyone reading who doesn't already know....

The AFRCC is phasing out 121.5/243.0 ELT satellite monitoring in 2008. It seems the frequncy used for EPIRBs 406.0250 will now become the ELT frequency.

So those who often monitored 121.5 might want to program in 406.0250 as well. And here is a link on this.

http://www2.acc.af.mil/afrcc/406 brochure.doc

 

[loumaag]

Take a look here and scroll down to sub-para (k). There you will find the approved emissions for 121.500 and 243.000. Included in the approved list is A3E, which is of course regular voice AM transmissions. 8)

 

[radioscan]

Post 9/11 a lot of the traffic is Sky Marshalls using it.

 

[nexus]

Take a look here and scroll down to sub-para (k). There you will find the approved emissions for 121.500 and 243.000. Included in the approved list is A3E, which is of course regular voice AM transmissions. 8)

(k) The frequencies 121.500 MHz and 243.000 MHz are emergency and
distress frequences available for use by survival craft stations,
emergency locator transmitters and equipment used for survival pruposes.
Use of 121.500 MHz and 243.00 MHz shall be limited to transmission of
signals and communications for survival purposes. Type A2A, A3E or A3N
emission may be employed, except in the case of emergency locator
transmitters where A3E, A3X and NON are permitted.


What I HEARD was NOT emergency in nature. I heard someone (presumed aircraft) talking to another station which I could not hear, and the communication was in no way shape or form emergency or survival. It was brief, but certainly just sounded routine.

 

[ReceiverBeaver]

You will hear " ON GUARD" callouts on 121.5 Essentially all aircraft have at least 2 VHF radios and all are supposed to monitor 121.5 at all times for the purpose of being able to receive an ON GUARD alert at any time. This pertains to Visual Flight Rules and other urgent purposes. When you have 2 craft coming into close proximity of each other, invariably 1 of the craft notices the situation first. They all have to have the capability of craft #1 calling out to craft #2 to say: "hey you white beechcraft, I'm here and we're getting close to each other, I'm right behind you ect...." Such a radio call is made on 121.5 This is a nationwide frequency....perhaps worldwide.

Here I will also mention the must-monitor freq. of 123.450 This is the pilot's casual chit-chat frequency. Can hear some interesting stuff here sometimes although most traffic is routine~casual. Sometimes a pilot will pick up the wrong mic and start a chat on 121.5 when they think they're on 123.45 I've heard an idiot ordering lunch down to his ground crew at a local airport on 121.5

This info comes from my own monitoring experience and questions put to a brother inlaw who flies 737's

ON GUARD,..... Continue having fun with radios ! Now dammit !

 

[INDY72]

Also remember that 121.5 is used to ask for any form of assistance, if its needed ASAP!

121.5 is also used to warn civilain aircraft to move away from an NFZ of any kind,.. and is used in MS by the FAA to tell News Choppers to CLEAR OUT when a TNFZ is requested by Law Enforcement..

All commercail aircraft have both 121.500 and 243.000 onboard.

As to Gaurd, Federal, and Fire Suppression aircraft have 3 Gaurd Frequencies.

 

[baybum]

Great info, are the 243 and 406 Mhz frqs AM or FM mode?

Mike

 

[mciupa]

are the 243 and 406 Mhz frqs AM or FM mode?
Mike

243.0000 = AM
406.0250 = FM

 

[unitcharlie]

although the rules are too often pre-9/11 they have been modified in practice to fit numerous situations none of us expected four years ago.... i have heard 121.5 used as a "hailing" freq of sorts when the normally assigned freqs haven't worked to identify the aircraft in question.... i have heard some seemingly routine traffic that, post 9/11, makes sense--some pilots, for example, nervous about their proximity to restricted airspace asking for a firm location from someone on the ground.... and yes, a number of real emergencies going on somewhere in the airspace above playing out on 121.5. we just gotta do what the old top sergeant taught us: adapt, improvise and overcome!

 

[INDY72]

Of course siad in a Clint Eastwood voice......



Semper Fi!

Oohrah!
Hoorah!
And the other two, though I forget them...

 

[nexus]

Of course siad in a Clint Eastwood voice......



Semper Fi!

Oohrah!
Hoorah!
And the other two, though I forget them...

"Be advised, I'm mean nasty and tired. I eat concertina wire and piss napalm and I could a round through a fleas ass at 300 yards. So why don't you hump somebody else's leg mutt-face before I push yours in."

 

[CORN]

I second Milf about the No-fly zone warnings. When Bush was in town (Nashville) and the CAP was in place I heard several voice comms on 121.500. Mostly the phrase pilots don't like to hear. From the fighters doing the CAP turn so and so degrees and vacate the area IMMEDIATELY!!

 

[K5MAR]

I second Milf about the No-fly zone warnings. When Bush was in town (Nashville) and the CAP was in place I heard several voice comms on 121.500. Mostly the phrase pilots don't like to hear. From the fighters doing the CAP turn so and so degrees and vacate the area IMMEDIATELY!!

Followed by the phrase "Or you will be shot down!".

Mark S.

 

[nd5y]

Here is an example I recorded a couple years ago.

BTW it's not "on guard" it's just "guard" or
VHF Guard 121.5
UHF Guard 243.0
FM Guard 40.50

Not all commercial aircraft have UHF radios, mainly only military and government ones.

Tom

 

[nd5y]

Maybe this will work

Tom

 

[INDY72]

Also Gaurd used by all USFS aircraft, and firefighting aircraft working with USFS-
168.6250

Thus you could hear the following phrases:

Go to Gaurd
Listen on Gaurd
Meet me on Gaurd
Use civilian Gaurd
Flight Ops will be advised on Low Gaurd...
Go High Gaurd
And- Smoke Jump Ops will be initial on Gaurd.

 

[CORN]

You will also hear that in the when military planes are cleared for takeoff. It's standard pretty much at military installations. Example here at Nashville airport last fall: "BAMA 11 flight (AL ANG F-16's x 4) at one DME turn left heading 180, climb and maintain one-five thousand, clear for takeoff, change to departure, monitor guard. It use to be that miltary tactical A/C or trainer A/C were UHF only. Now more and more of them are equiped with both, UHF and VHF, so they can monitor one or the other guard frequencies of 121.500 or 243.000 since the ELT operates on both at the same time.

 

[nexus]

this has all been very informative...

I guess since 9/11 a lot of things have changed. 121.5 use to be very silent except for the occasional mission for an elt, or an epirb being set off accidently. I've been credited with 5 finds in my service with CAP. It just threw me off to hear a casual conversation on it.

 

[Chris-M]

re: 121.5

There are mutiple reasons voice traffic on 121.5 mhz has become common. The FAA issued the following NOTAM a while back.

FDC 4/4386 FDC SPECIAL NOTICE...
National Airspace System Intercept Procedures. Aviators shall review the Federal Aviation Administration Aeronautical Information Manual (AIM) for Interception Procedures, Chapter 5, Section 6, Paragraph 5-6-2. All aircraft operating in United States National Airspace, if capable, shall maintain a listening watch on VHF Guard 121.5 or UHF 243.0. If an aircraft is intercepted by U.S. Military Aircraft , the following procedures are to be followed: Follow the intercept's visual signals, contact Air Traffic Control immediately on the local frequency or on VHF Guard 121.5 or UHF Guard 243.0 and comply with the instructions given by the intercepting aircraft including visual signals if unable radio contact. Be advised that noncompliance may result in the use of force.

Since every airborne VHF equipped aircraft with an available receiver (most have 2 VHF transceivers) are required to monitor 121.5, a local FAA control facility (tower, departure or arrival etc) controller might broadcast 'in the blind' to a specific aircraft to get the pilots' attention.
One example. Airliners switch frequencies often while enroute and sometimes miss a 'handoff' to the next controller. Within minutes the aircraft is out of VHF line-of-sight radio range of the previous ground-based facility. They can still hear the other airborne aircraft talking though. It's common for a local, nearby FAA facility to transmit on 121.5 'in the blind' for them to swich to a specific frequency. Also the company dispatcher can send an ACARS message to the flight deck crew that the controllers are looking for them, that they missed a handoff.

Also since 121.5 is dialed in to the #2 receiver, sometimes we pilots forget to swich (flipflop) the frequency when calling company Operations with the ETA or other messages or info. When someone accidentally does this, other aircraft monitoring Guard will say, "(you're) on Guard" to let them know that they forgot to switch the radio. (The control head has 2 frequency positions, one is the in use freq and the other is the standby freq. There is a button to 'flip flop' them, and sometimes that is overlooked).

As for Air Marshalls using Guard. Nope..they are 'incognito' and do not use radios. When they are on board an airliner, they blend in with the crowd and only appear when they feel the cockpit crew is in danger. The whole crew, pilots and flight attendants, knows that they are on board and who they are.

There are a couple of common 'air to air' frequencies that are interesting to listen to. One is 122.75 and the other is 123.45. There are others but these are the most common, standard ones.