BA81 [LHR-ACC B744 G-CIVN] returned to LHR [and might have declared an emergency?]
Mar 24, 20, 3:58 am
#16
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Originally Posted by florens
I am no pilot but shouldn't they avoid exactly this, and instead select their transponder code in a way that it doesn't come to a temporary 7700?
For all I know, they might well have had a reason to squawk 7700 on this particular flight which was subsequently resolved, though.
Mar 24, 20, 6:01 am
#17
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It's my understanding that ATC can sometimes ask a flight to sqwuak 7700 as it then highlights that flight on the controller's radar screen. In the situation described in this thread, I could see this happening as it would allow the controller to instantly see the aircraft on his screen and be able to deconflict it from other traffic.
Mar 24, 20, 6:46 am
#19
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Originally Posted by GadgetGal
Just thinking about last yesterdays flight: there will be crew caught up n this well if BA 78 didn't run. Are they effectively stuck there until 5th April?
Mar 24, 20, 8:36 am
#20
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Originally Posted by McG
It's my understanding that ATC can sometimes ask a flight to sqwuak 7700 as it then highlights that flight on the controller's radar screen. In the situation described in this thread, I could see this happening as it would allow the controller to instantly see the aircraft on his screen and be able to deconflict it from other traffic.
Mar 24, 20, 10:27 am
#23
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Originally Posted by flygirl68
No, they were going to be working out and coming home as passengers, and another crew doing it the other way round.
So there was no 24 rest with the crew staying down route? Fair enough
Mar 24, 20, 10:41 am
#24
Join Date: Nov 2011
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ATC can ask crew to select 7700 as it will show up through any suppressing filters on any radar screens, enabling all ATC other staff to see any 7700 squawk in any neighbouring airspace. This is helpful because it tells the controller not to try and contact them unless absolutely necessary.
Additionally, crews can sometimes select 7700 inadvertently on the way to selecting their intended squawk, however this is often not possible on the avionics most modern airliners have installed. It’s far more common on light general aviation aircraft, indeed I’d say around London it’s a daily occurrence. When I see 7700 come up on my screen for an aircraft not under my control, I wait at least 5 seconds before reporting it.
Additionally, crews can sometimes select 7700 inadvertently on the way to selecting their intended squawk, however this is often not possible on the avionics most modern airliners have installed. It’s far more common on light general aviation aircraft, indeed I’d say around London it’s a daily occurrence. When I see 7700 come up on my screen for an aircraft not under my control, I wait at least 5 seconds before reporting it.
Mar 24, 20, 10:54 am
#26
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Originally Posted by SkyTeem
There's an "IDEN" button on transponders that highlights a particular aircraft to ATC - they'll often ask "Squawk IDEN" to get a highlight on their screens in periods of heavy traffic. I can't imagine ATC ever asking for a 7700, but maybe in other parts of the world?
We regularly ask for the 7700 if an aircraft is in an emergency so that all of the surrounding sectors can see that there's an issue-particularly to indicate that an emergency descent may be required
this is a very simple explanation
Last edited by steve170461; Mar 24, 20 at 11:59 am
Mar 24, 20, 3:53 pm
#29
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Originally Posted by Heathrow Tower
ATC can ask crew to select 7700 as it will show up through any suppressing filters on any radar screens, enabling all ATC other staff to see any 7700 squawk in any neighbouring airspace. This is helpful because it tells the controller not to try and contact them unless absolutely necessary.
Additionally, crews can sometimes select 7700 inadvertently on the way to selecting their intended squawk, however this is often not possible on the avionics most modern airliners have installed. It’s far more common on light general aviation aircraft, indeed I’d say around London it’s a daily occurrence. When I see 7700 come up on my screen for an aircraft not under my control, I wait at least 5 seconds before reporting it.
Additionally, crews can sometimes select 7700 inadvertently on the way to selecting their intended squawk, however this is often not possible on the avionics most modern airliners have installed. It’s far more common on light general aviation aircraft, indeed I’d say around London it’s a daily occurrence. When I see 7700 come up on my screen for an aircraft not under my control, I wait at least 5 seconds before reporting it.
