7600 vs. 7700?

Old Dominion Flyer

Old Dominion Flyer

Well-Known Member
What warnings/alarms does a controller receive when a pilot sets their transponder to 7600 or 7700? Are they the same? Does one get your attention more than the other?

The reason I ask: You're on an IFR flight plan in IMC and encounter a two-way communications failure. A local DPE encourages squawking 7700 for a minute to get the controllers attention, then switching to 7600 to communicate that the nature of the emergency is lost comm.

This practice differs from my understanding of the procedure, whereby 7700 is used for immediate safety of flight issues, and 7600 is used strictly for lost comms.
 
Old Dominion Flyer said:
What warnings/alarms does a controller receive when a pilot sets their transponder to 7600 or 7700? Are they the same? Does one get your attention more than the other?

The reason I ask: You're on an IFR flight plan in IMC and encounter a two-way communications failure. A local DPE encourages squawking 7700 for a minute to get the controllers attention, then switching to 7600 to communicate that the nature of the emergency is lost comm.

This practice differs from my understanding of the procedure, whereby 7700 is used for immediate safety of flight issues, and 7600 is used strictly for lost comms.
Click to expand...

The old method of NORDO announcement to ATC used to be 7700 for 1 minute, then 7600 for 15 minutes; then repeat. It's since been changed to just going to 7600 at the outset.
 
I listened to a controller in Columbus, GA talking to a plane that had suffered comms failure. He had immediately picked up on the 7600 squawk and the way they established communication was through transponder idents. The controller did a really good job and asked questions like, "do you wish to return to the airport, ident if yes" etc.
It was like a knock once for "yes" and twice for "no" scenario.

Through the whole thing the controller kept telling the pilot "don't hesitate to squawk 7700 at any time if you feel unsafe or uncomfortable".

I was impressed, it all worked out fine and it seemed that the pilot never did squawk 7700.

Not very pertinent to the thread I suppose, but I really appreciated the way the controller did his job - very calm and knew exactly what he was about.

Bp244
 
Baronpilot244 said:
I listened to a controller in Columbus, GA talking to a plane that had suffered comms failure. He had immediately picked up on the 7600 squawk and the way they established communication was through transponder idents. The controller did a really good job and asked questions like, "do you wish to return to the airport, ident if yes" etc.
It was like a knock once for "yes" and twice for "no" scenario.

Through the whole thing the controller kept telling the pilot "don't hesitate to squawk 7700 at any time if you feel unsafe or uncomfortable".

I was impressed, it all worked out fine and it seemed that the pilot never did squawk 7700.

Not very pertinent to the thread I suppose, but I really appreciated the way the controller did his job - very calm and knew exactly what he was about.

Bp244
Click to expand...

Completely pertinent, and good to know the different techniques employed by ATC in order to manage a situation like this where a pilot can't transmit, but can't receive.

The worst NORDO is the one associated with complete electrical failure in IMC, where there's not only no comm ability, but no nav ability anymore. You can't see or talk, and ATC can't really see you all that well.
 
On ACD scopes (and I'm 99% certain STARS) all 7XXX codes turn the same shade of crimson/flash. The much older ARTS IIIE and IIE though I really don't remember. From everything I've heard about the unicorn that is MEARTS, it probably just diagnoses and repairs/solves the emergency/radio remotely and instantly while it hands you a slice of pie.

Basically what Mike said. 7600 grabs our attention plenty. That said, hanging out at the main airport with a 7XXX code in the xponder, batt switch on, engine off, just chillin at the GA ramp for a few hours drives us radar people up the wall.
 
genot said:
On ACD scopes (and I'm 99% certain STARS) all 7XXX codes turn the same shade of crimson/flash. The much older ARTS IIIE and IIE though I really don't remember. From everything I've heard about the unicorn that is MEARTS, it probably just diagnoses and repairs/solves the emergency/radio remotely and instantly while it hands you a slice of pie.

Basically what Mike said. 7600 grabs our attention plenty. That said, hanging out at the main airport with a 7XXX code in the xponder, batt switch on, engine off, just chillin at the GA ramp for a few hours drives us radar people up the wall.
Click to expand...


Yeah that

only difference is the 7700 shows a red flashing "EM" while the 7600 shows a red flashing "RF", both are equally attention getting.
 
We also have an aural alarm that blares when any of the emergency codes are detected by our radar. It is VERY loud, VERY piercing, and the panel to shut it up is mounted up high so it takes a second to get to it.

Squawking 7700, then 7600, would cause that thing to go off twice. Not cool/necessary :D
 
Isn't this issue directly addressed in most if not all written tests? The fact that the examiner is promoting a procedure that is no longer in use is a bit troubling. I wonder how many pilot's he has infected with this mis information?
 
On center scopes it will flash EMG or RTF there may be an alarm for it but I wouldn't know we keep our alarms shutoff.
 
It would seem that putting 7700 up initially wouldn't be the greatest idea...let's say you do that and atc starts trying to communicate with you to find out the emergency and what your intentions are, but you can't communicate. Now the controller has to go to plan b,c,d...ect when you could have just avoided it in the first place and done 7600 and left a lot less information in the realm of the unknown
 
Just make sure you don't bump it down one more digit...then things start to get real interesting. HJK starts flashing...then there is one more code that flashes, but not sure if that one is published.
 
For us the datatag including the target symbol and everything turns deep red, it flashes EMG or RDO above the tag and also we have a British female bitching Betty that yells stuff at us but in a futuristic movie with that calm "You're screwed" tone of voice.

"Emergency"
"Radio Failure"
"Traffic"
And everyones favorite
"CONFLICT!"

"20% atttttmosphere" -(for those who get thus reference that's what her voice sounds like)
 
MikeD said:
The old method of NORDO announcement to ATC used to be 7700 for 1 minute, then 7600 for 15 minutes; then repeat. It's since been changed to just going to 7600 at the outset.
Click to expand...

Mike is correct and DE is wrong. It bothers me that DE would be teaching an outdated procedure. I was told when the changeover occurred the practice of sqauwking 77 then 7600 was causing confusion and squawking 7600 from the outset was a lot more clear and to the point.
 
You must log in or register to reply here.
Back
Top