ATC opinion please
 

Hi

Just a quick question from something that came up during one of our technical training days and I guess it is probable aimed more at the area controllers than terminal ones.

If we suffer a rapid decompression and have to initiate an emergency descent, is the preference nowadays for us to set 7700 as well as making a Mayday call or if we are identified and receiving a service to maintain our original squawk?

Cheers

I'm not an area controller but I am 99.9% sure the preference is to set 7700. I believe on all modern displays/radar processors this highlights your aircraft and maintains the callsign.

Prepare for higher authority...

Preferably both (if you have the time). It gets the adrenaline running all round the units, also 'cos of transfer to another sector/unit it initiates the back up to help you out.

I am a UK area controller and I personally would prefer you to select 7700 but if you are looking for that in writing in a document then I'm not sure it is! Selecting 7700 puts a flashing red and yellow box around the datablock but the information is still the same. If you make a Mayday call stating emergency descent, the natural response will be "squawk 7700" in nearly every case.

From the UK area side, it also cuts through any height filters controllers might have selected on the radar so coordination can be effected a lot quicker should it be required

Talk Mayday = Squawk Mayday. No question. Don't faff about.

Flashes
Forces through
Retains data block at some ACCs
Attracts attention and support
In your interest too...

As long as it's safe for you guys to do so in the cockpit, definitely do both! Squawking 7700 is a lot quicker for us to see and start getting other traffic out of your way.

As a non-SSR bod, 'ADS Emergency' please, ASAP...:ok:

Eau de Boeing
 

The best guidance [UK] can be found in United Kingdom Aeronautical Information Circular P138/2012 "Emergency Descents in UK Controlled Airspace"
The P stands for pink...because it is safety related. The AIC will explain slight UK differences from ICAO and is worth a read; it also gives an explanation to some other questions.
I prefer the AIC guidance rather than the more sterile interpretation given in the UK AIP En Route section.... ENR 1.6 SSR Operating Procedures..... page ENR 1.6-3 para 2.2.1[a].
Sorry I can't do the cut and paste thing........but if you really want to know you will find it. rgds

Sorry...should have said...NATS | AIS

Setting 7700 also makes sure you are front page news! Thanks to the likes of flightradar24 etc!

You sould do whatever your SOP tell you, as far as I know it was a checklist item.