I'm puzzled. Over the past couple of weeks, for obvious reasons, our media here in the UK have been showing B777 simulators (full motion) and have been homing in on a switch which is supposedly to the left of the squawk transponder, which can be turned to switch it off. Other conflicting reports say it is not as easy as that.

 

I cannot find such a switch on the configs of the T7 that I use on FlightSim. Does this switch exist on any examples? I cannot believe that PMDG got this wrong.

 

It does beg the question why would you want to switch the transponder off?

 

Iain Smith

 

 

squawk transponder

 

Just "transponder."

 

Squawk is the term used to tell a pilot to change the code on the transponder.

 

 

 

Other conflicting reports say it is not as easy as that.

 

It is and it isn't.  You can't make a plane disappear simply by turning a transponder off (with certain limitations).

 

 

 

Does this switch exist on any examples? I cannot believe that PMDG got this wrong.

 

There are several different types of transponders available on the Boeing 777.  Have a look at the examples in the FCOM.  PMDG modeled only one of them for simplicity.  Either way, the modeled transponder also has an off position.

 

Word of wisdom: if it's on the news, it's probably not entirely correct.  They're terrible at aviation facts.

There are multiple transponder panels available to airlines as option:

 

Bendix 071-01503-2901

Gables G7131-01, -02

Gables G7131-03, -04

Gables G7156-01

 

PMDG Gives us only Gables G7131-01, -02

 

You would want to switch off transponder when you are on ground parked or in taxi (if airport doesn't have ground tracking system), or when you fly formation...

The transponder has an adjustable knob with the positions: STBY, ALTN, XPNDR, TA, TA/RA. There's also a smaller transponder selector knob on the upper-left corner of the panel, it can be positioned on either the left "L" or right "R" transponder.

 

Turning the transponder off means selecting "STBY".

 

There are many situations in which the crew should set the transponder to "TA only" (If you've gone through engine failures and such you've surely seen it on the electronic checklist). 

 

I can't imagine of a situation in which the crew has a legitimate reason to turning it off completely, however that doesn't mean such a situation doesn't exist.

 

EDIT: Question to the experts: Does the xpndr mode selector control both xpndrs or only the one selected on the "L" or "R" knob? I couldn't find the answer to that on the FCOM.

 

Oddly enough, information on the transponder is on chapter 11, Flight Management and Navigation, not chapter 5 Communications where I checked first.

 

 

EDIT: Question to the experts: Does the xpndr mode selector control both xpndrs or only the one selected on the "L" or "R" knob? I couldn't find the answer to that on the FCOM.

 

It only controls the one that is currently selected.  The other is forced to standby.  Only one may be queried at a time.  Can't have multiple transponders responding to queries for other transponders.  If you did, you'd have multiple secondary targets popping up on the same primary target.

It only controls the one that is currently selected.  The other is forced to standby.  Only one may be queried at a time.  Can't have multiple transponders responding to queries for other transponders.  If you did, you'd have multiple secondary targets popping up on the same primary target.

 

Sure that makes sense! Could have figured that out myself had I not been lazy and thought it through! haha

 

 

Word of wisdom: if it's on the news, it's probably not entirely correct. They're terrible at aviation facts.

 

Well! You don't say? I'd guess I've been around longer than you so I'm well aware of that. Why do you think I posted the question here?

 

Thanks for your response Kyle but it could have done without your "word of wisdom".

 

Iain Smith

Thanks Alpha Floor and g_precentralis for your responses.

 

Iain

 

 

Thanks for your response Kyle but it could have done without your "word of wisdom".

 

You posted here clearly using false terminology, that I could only guess came from either the news or some half-wit simmer who claimed to know what he or she was talking about.  From there, I had to assume you believed one of those two.  As such, I merely pointed out that the news isn't the best source of aviation facts, procedures or reality.  It wasn't meant to be a snide comment.

 

Sorry for coming to your aid...I won't make the mistake again...

Well! You don't say? I'd guess I've been around longer than you so I'm well aware of that. Why do you think I posted the question here?

 

Thanks for your response Kyle but it could have done without your "word of wisdom".

 

Iain Smith

Thanks Alpha Floor and g_precentralis for your responses.

 

Iain

 

or some half-wit simmer who claimed to know what he or she was talking about

Kyle

 

No care bears, hugs, or rainbows here. Just the unvarnished truth. Keep on telling it like it is.

 

Michael Cubine

No care bears, hugs, or rainbows here. Just the unvarnished truth. Keep on telling it like it is.

Haha - I've had a wonderful head cold all week, so I've been on healthy doses of cold meds. Those always reduce my already thin filter.

Well! You don't say? I'd guess I've been around longer than you so I'm well aware of that. Why do you think I posted the question here?

 

Thanks for your response Kyle but it could have done without your "word of wisdom".

 

Iain Smith

Thanks Alpha Floor and g_precentralis for your responses.

 

Iain

 

Your profile claims you're 70, but you write like a sarcastic teenager.

Well! You don't say? I'd guess I've been around longer than you so I'm well aware of that. Why do you think I posted the question here?

 

Thanks for your response Kyle but it could have done without your "word of wisdom".

 

Iain Smith

(...)

 

Judging Kyle's first post in your topic in its entirety, your harsh way of replying kinda surprises me, Ian ...

Ok, my apologies to Kyle and everyone. You're all absolutely right, I was unnecessarily harsh to Kyle when he was only intending to help.

 

No excuses and I won't blame anyone who ignores me from now on.

 

Iain Smith