Squawking 7700

[DICKUS]

If we have an emergency, and then change the squawk to 7700, does this now present an identification problem? Is it permissible to leave the last two existing digits, and does that then provide easier identification, i.e. 77XX?
Under a radar control environment, would it be better to leave the transponder alone so that identification does not alter?
Do the "alarm bells" only go off when the squawk is 7700 or 77XX as well?

[Little One]

there was a similar question posted on the question page a few weeks ago.

You must change your transponder to 7700 as say you where squawking 2431 then 7731 would be another SSR code that can be allocated to some one else.

On our system the label starts to flash when 7700 ,7600 or 7500 is dialed in to your transponder with the leters EMRG, RCF or INT under the radar label respectivly

I'm stupid with computors so you can go look at squawk posted 9 feb on the questions page as well (I' don't know how to make a link sorry) On the new system that we have now bought the label will change to be red in colour.

Your concern about identing is also answered there.

Good question though comes up a lot.

I think this will make a link to the page

www.pprune.org/forums/showthread.php?threadid=80987&referrerid=58633

[Arkady]

In the UK, and I would imagine most other places, squawking 7700 has the advantage of burning through any height filters that may be set in vertically divided airspace. Lower sectors can then anticipate moving their traffic out of the way in the event of a rapid descent.

Having a 7700 squawk in the sector also ensures increased attention from the surrounding sectors, they answer the phone more quickly, anticipate co-ordination and, if possible, avoid your airspace all together.

[Dropped Chinagraph]

On the ScATCC system, a squawk that has been code callsign converted, as 99% of tracks under service are, will retain the callsign, but the whole label will flash and indicate an emergency code. Thus there is no problem with retaining identity. Also, the alrms in the Distress & Diversion Cell only work with 75/76/7700 squawks.

[FWA NATCA]

DICKUS,

When you squawk 7700 I still see your full acft call sign, type, speed and altitude in the data tag, but I also see EM flashing in your tag, and it sets off an alarm.

Now to answer your question, I've seen acft using 7700 with the zeros being other numbers set off the alarm and have EM flash in the data tag.

Like others have said, you will get our undivided attention if you squawk 7700.

Mike
NATCA FWA

[expedite_climb]

Hmm, interestingly, i've had an ATC allocated squawk such as 7736 before.... thought it was a bit close