peh
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Questions Re: Squawk 7600

Mon Feb 11, 2013 2:54 am

QFA93 just squawked 7600 (radio/communication failure) and then disappeared from the screen.

Q1) Is it possible that the communication failure related to the transponder and that's why the plane is no longer visible?
Q2) What's the procedure following a 7600 squawk? Does the plane have to make an immediate landing or can it continue to its destination?

Thanks in advance for the info!
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wilco737
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RE: Questions Re: Squawk 7600

Mon Feb 11, 2013 10:18 am

Quoting peh (Thread starter):
What's the procedure following a 7600 squawk? Does the plane have to make an immediate landing or can it continue to its destination?

The official procedure is generally spoken: Continue on your flight plan to your destination and follow the flight plan as closely as possible.

But if this would be done in real life is another question. I am not sure if I want to fly from FRA to the US without a clearance for the NAT or flying eastbound over Afganistan, Iran, Iraq without entry clearance...

wilco737
  
 
jgarrido
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RE: Questions Re: Squawk 7600

Mon Feb 11, 2013 11:19 am

Quoting peh (Thread starter):
Q1) Is it possible that the communication failure related to the transponder and that's why the plane is no longer visible?

If i were to guess I would say that the comm failure is possibly part of a larger problem, electric/electronic in nature, which caused the transponder to stop operating.
 
CosmicCruiser
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RE: Questions Re: Squawk 7600

Mon Feb 11, 2013 1:31 pm

most airliners have 2 transponders
 
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Starlionblue
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RE: Questions Re: Squawk 7600

Mon Feb 11, 2013 3:50 pm

Quoting wilco737 (Reply 1):
Quoting peh (Thread starter):
What's the procedure following a 7600 squawk? Does the plane have to make an immediate landing or can it continue to its destination?

The official procedure is generally spoken: Continue on your flight plan to your destination and follow the flight plan as closely as possible.

IFR rules in the US are as follows.

Altitude should be the highest of:
- Assigned Altitude
- Expected Altitude
- Minimum Enroute/Safe Altitude

Route in descending order of priority:
- Assigned
- Vectored
- Expected
- Filed

Leaving the clearance limit:
- Plan to leave the clearance limit of the IAF at the time in your flight plan.
- If you arrive at the clearance limit before then, hold there until that expected arrival time.

Quoting wilco737 (Reply 1):
But if this would be done in real life is another question. I am not sure if I want to fly from FRA to the US without a clearance for the NAT or flying eastbound over Afganistan, Iran, Iraq without entry clearance...

As you say. In ALL cases, make decisions in accordance with safety, as that is your primary concern. The rules don't absolve you from using your brain to make sound decisions. 
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
KELPkid
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RE: Questions Re: Squawk 7600

Mon Feb 11, 2013 4:39 pm

Quoting Starlionblue (Reply 4):
As you say. In ALL cases, make decisions in accordance with safety, as that is your primary concern. The rules don't absolve you from using your brain to make sound decisions.

Exactly. If I ever found myself in a lost comms situation, and if I encountered decent VFR conditions, I would probably just land at an uncontrolled field (one with decent repair facilities) and phone the Flight Service Station to report being safely down and to cancel IFR  
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NWADC9
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RE: Questions Re: Squawk 7600

Mon Feb 11, 2013 5:21 pm

If VFR: Remain VFR and land as soon as practical.

If IFR: The MEA AVEF rule applies as mentioned earlier.
Flying an aeroplane with only a single propeller to keep you in the air. Can you imagine that? -Capt. Picard
 
113312
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RE: Questions Re: Squawk 7600

Wed Feb 13, 2013 8:11 pm

You said that the flight disappeared from the screen; which screen? Flightaware, ATC display? Different sources drive different displays with respect to ATC or publicly available internet sources. Internet tracking usually involves a feed from an ATC that might be based on transponders or ADS sources. ATC can also filter what is fed out to internet sources.

This original post does not provide sufficient information to give an accurate answer.
 
Mir
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RE: Questions Re: Squawk 7600

Thu Feb 14, 2013 12:48 am

Quoting Starlionblue (Reply 4):
IFR rules in the US are as follows.

A good summary, but you forgot the first one: if you're in VMC, continue the flight under VFR and land as soon as practical.

Since you're rarely going to be in IMC for an entire flight, that's likely going to apply to you at some point.

-Mir
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Starlionblue
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RE: Questions Re: Squawk 7600

Thu Feb 14, 2013 1:07 am

Quoting Mir (Reply 8):
Quoting Starlionblue (Reply 4):
IFR rules in the US are as follows.

A good summary, but you forgot the first one: if you're in VMC, continue the flight under VFR and land as soon as practical.

Since you're rarely going to be in IMC for an entire flight, that's likely going to apply to you at some point.


Fair point. I guess I took it for granted. Big grin

[Edited 2013-02-13 17:08:44]
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
SPREE34
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RE: Questions Re: Squawk 7600

Thu Feb 14, 2013 4:54 am

Quoting 113312 (Reply 7):
You said that the flight disappeared from the screen; which screen?

^^^^^This.
I don't understand everything I don't know about this.
 
Mir
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RE: Questions Re: Squawk 7600

Thu Feb 14, 2013 5:51 am

Quoting Starlionblue (Reply 9):
I guess I took it for granted.

You wouldn't be the first. When I was helping people prepare for their instrument checkrides, I'd ask them what would happen if their radio failed and 90% of them went straight to what course they'd fly, what altitude they'd fly, etc. Which is all well and good, but if you start going through all that when it's severe clear outside, you're missing the forest for the trees.

-Mir
7 billion, one nation, imagination...it's a beautiful day
 
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Starlionblue
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RE: Questions Re: Squawk 7600

Thu Feb 14, 2013 8:34 am

Quoting Mir (Reply 11):
Quoting Starlionblue (Reply 9):
I guess I took it for granted.

You wouldn't be the first. When I was helping people prepare for their instrument checkrides, I'd ask them what would happen if their radio failed and 90% of them went straight to what course they'd fly, what altitude they'd fly, etc. Which is all well and good, but if you start going through all that when it's severe clear outside, you're missing the forest for the trees.

Thankfully my examiner didn't ask me then! She was focused more on things like tailplane icing on approach-  Wow!
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
Pihero
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RE: Questions Re: Squawk 7600

Thu Feb 14, 2013 12:42 pm

Nice discussion.
A modern airliner is equipped with
- 3 VHF sets
- 1 ACARS
- 1 SatCom
- 2 transponders

If a long haul airliner, it will have furthermore
- 2 HF sets
all on different buses.
So, a complete radio failure is sometrhing which is at the very least very remote... so that if it happened, you'd have a lot more on your hand than just lack of communications : In this respect, the first item of the loss of communication procedure, after A7600, is to establish a two-way link with someone with all the means available... then, and only then, we'd start following the official loss of com procedures... which vary from one place to another, one flight condition to another, one area to another... all are published in the local AIP.
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jbcarioca
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RE: Questions Re: Squawk 7600

Tue Feb 26, 2013 4:06 pm

Seems very likely that a modern airliner encountering a total communications failure probably would be inclined to squawk 7700 rather than 7600 because there would be many, many things going very wrong. 7600 can easily happen with small aircraft that do not have backup systems but that would be vanishingly rare in a modern airliner.
 
PITrules
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RE: Questions Re: Squawk 7600

Sun Mar 03, 2013 2:12 pm

Quoting Mir (Reply 8):
A good summary, but you forgot the first one: if you're in VMC, continue the flight under VFR and land as soon as practical.

From an ATC perspective, they have no idea when a flight may encounter VMC conditions. There is expectation bias on their part as to what the flight will do. An IFR flight starting a 360 spiral just to stay VMC at a moments notice might not be the best idea. I have met many controllers who said they would just prefer a flight continue on its flight planned (and expected) route. They have the route cleared to destination.

Quoting Starlionblue (Reply 12):
Thankfully my examiner didn't ask me then! She was focused more on things like tailplane icing on approach-

Thankfully, your examiner has a big picture, and focused on things which are really critical to safety.

[Edited 2013-03-03 06:21:28]
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atct
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RE: Questions Re: Squawk 7600

Sun Mar 03, 2013 9:24 pm

Usually when an airliner goes nordo, its just for a few minutes. Due to somebody bumping a switch, headset unplugged, etc. I cant think of the last time someone went nordo for more than 10 minutes. (Except those guys in Hawaii and Northwest at MSP...different circumstance).

If you were using a third party software to see the flight, it probably disappeared because its transponder code switched to a non-discreet code that it didnt recognize. On my scope, if someone squawks 7600, a little red "RF" appears above their tag and an audible alarm goes off. The tag still shows the previous code's information, but im not using third party software  

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