PPRuNe Forums - Transponder ALT reporting on or off in B777?

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Transponder ALT reporting on or off in B777?

In some airports they required to turn ALT reporting on on the ground.
But in B777 the ALT reporting (mode C) is inhibited on ground even we set the selector knob to XPDR position(FCOM)
so how can we comply with this?

On the otherhand some airport required to select ALT reporting off during ground movement but do the mode S still send the aircraft altitude out or not
or just even inhibit altitude reporting in mode C only?

Perhaps you could give an example of where this is required.

Thanks

Would not the 777 have ADS-B? So ALT reporting would be inhibited but ADS-B would enter GND mode?

IIRC, YSSY, YMML and several others with newer ATC systems have the ability to electronically squelch ALT returns, yet utilise the ADS-B return for ground movements.

The US FAA says as much in their AIM:

Quote:

. Aircraft equipped with ADS−B (1090 ES or UAT) must operate the equipment in the transmit mode (on position) at all times while on any airport surface.
NOTE− Pilots of aircraft equipped with ADS−B should refer to AIM, Automatic Dependant Surveillance − Broadcast Services, Paragraph 4−5−7, for a complete description of operating limitations and procedures.

And from the Australian AIP ENR 1.6 7.1.9:

Quote:

A pilot operating a Mode S transponder must:
a. Enter the aircraft’s identification that corresponds exactly to the Aircraft Identification shown in Item 7 of the flight
notification filed with ATC for the flight; for those aircraft that are capable of reporting Aircraft Identification. The ICAO
defined format for entry of the Aircraft Identification shall be used except for domestic operations when VH is not to be
entered on the flight notification. (e.g. VOZ123D, REX638, QFA842, VHQFO (international), FDA...)
b. On receipt of ATC clearance, or requesting the earlier of Push Back or Taxi, select TA/RA/XPDR/ON AUTO as applicable.

DEL-VIDP 1-10 Lido chart
Transponder operation
On gnd squawk mode C

But how can I do that Because Mode C was inhibited on gnd for 777

Could you provide a screenshot from the LIDO chart?

I believe they mean mode S auto. This allows for data exchange.

Jepp:

https://i.imgur.com/HOh6MY7.jpg

The Jepp chart does mention this at VIDP on page 10-1P6.

[QUOTE=underfire;9927160]Could you provide a screenshot from the LIDO chart?

I believe they mean mode S auto. This allows for data exchange.

Jepp:

https ://ibb.co/iPq60m

Sorry This for BOM VABB but Delhi still be the same

Ican not post URL because I have not reach 10 posts

So you may copy the URL above and delete the space after https

i found a Jepp chart (I could not open your link)

https://i.imgur.com/pevU9wB.jpg

In regards to your question, once there is weight on wheels, it goes into GRN mode anyways. There must be something in their system that a squawk mode C ( Mode S ac ID, location, and alt with interrogation) that it understands to null the ac out from the system.

The other steps appear typical of surface movement systems.

Thank you so much.
So we can make sure that some airports required alt reporting on but some required alt/off
It depends on their system.
Then I will try my best to comply with.