Hi all

i've got a question couple of hours ago,went and checked out the FCOM,but nothing

how can i manually engage A/P num. 1 or 2(like on bus[1/2] or 757-767-747[L/C/R] or 737NG[A/B])?what is A/P-#1 or #2 ADR source?does FMC selector knob select A/P FMC source?what about ADR reference?

 

and what about this case:

if i want to fly as a cm1 and altimiter #1 in qnh 1012 indicates 9895 ft and altimiter #2 is in qnh 1011 and indicates 10010 ft,and if i want to alt hold at 10000ft,which altimiter A/P relay on and follow

Hi all

i've got a question couple of hours ago,went and checked out the FCOM,but nothing

how can i manually engage A/P num. 1 or 2(like on bus[1/2] or 757-767-747[L/C/R] or 737NG[A/B])?what is A/P-#1 or #2 ADR source?does FMC selector knob select A/P FMC source?what about ADR reference?

 

and what about this case:

if i want to fly as a cm1 and altimiter #1 in qnh 1012 indicates 9895 ft and altimiter #2 is in qnh 1011 and indicates 10010 ft,and if i want to alt hold at 10000ft,which altimiter A/P relay on and follow

 

 

Autopilot engagement, and therefore which EFIS Baro setting the A/P references, is dependent on which A/P button is pressed first. See Section 10.10.20 of B777 Flight Instruments and Displays.

The 777 only has one Autopilot switch on the MCP - it does still have three autopilots. Unlike in the NGX, if you wanted a CAT3B approach, you'd have to put on both AP's. The 777 however sets you up for it automatically with the AP & APP modes on. I think the 747/76/75 may work in a similar fashion, once LAND3/ROLLOUT/FLARE are armed, it activates all autopilots without you having to do it manually. I think you're trying to ask if there's an alternate autopilot switch?

 

What do you mean by ADR? I've read the FCOM lots, not seen any reference to it. Maybe you're trying to talk about the ADIRS/ADIRU/SAARU systems?

ADR:air data reference

ADIRU:air data and inertial reference unit

IRS:inertial reference system

 

thank you flamin,really helped!

But one still remaining:if i want to change the a/p during flight(after first engagement),what procedure i have to procee

What is the difference between ADIRU and ADIRS ? The same ?

What is the difference between ADIRU and ADIRS ? The same ?

The Air Data Inertial Reference System (ADIRS) basically calculates all the information for the aircraft's attitude, altitude, heading etc - just like the 737's IRS. The Air Data Inertial Reference Unit (ADIRU) supplies all the primary flight data, inertial reference and air data to the aircraft's instruments.

 

Unlike older Boeing aircraft, the 777's Inertial Reference Systems are aligned with the one click ADIRU switch on the top left on the overhead panel.

 

Hope that answered your question.

 

ADR:air data reference

ADIRU:air data and inertian reference unit

IRS:inertial reference system

 

See my post above.

What do you mean by ADR? I've read the FCOM lots, not seen any reference to it. Maybe you're trying to talk about the ADIRS/ADIRU/SAARU systems?

i answered your question egll

but my question's still remaining:what about switching autopilots?

i answerd your question egll

but my question's still remaining:what about switching autopilots?

There's only one Autopilot button on the 777. You cannot manually switch between the other two because it's entirely automatic. If you want an ILS CAT3 approach the aeroplane will automatically prepare all the autopilots without any input from yourself. Assuming you have AP & APP engaged. Beyond that, I can't think why you'd need to switch between the different AP's.

Thanks Luke !

seems you didnt get it,i didnt even write a word abou ils at all !i'm not talking about ILS ! >: !i'm talking about changing pf and pnf

There's only one Autopilot button on the 777. You cannot manually switch between the other two because it's entirely automatic. If you want an ILS CAT3 approach the aeroplane will automatically prepare all the autopilots without any input from yourself. Assuming you have AP & APP engaged. Beyond that, I can't think why you'd need to switch between the different AP's.

 

There are two A/P buttons. You should know this!

There are two A/P buttons. You should know this!

Yeah, one for Capt and one for FO. Both linked - they're not like "AP1" & "AP2" :-P

 

seems you didnt get it,i didnt even write a word abou ils at all !i'm not talking about ILS ! >: !i'm talking about changing pf and pnf

I was using that as an example for when you'd need all the autopilots. There's only ONE switch (yes two for Capt & FO which are both linked..) (-:

Yeah, one for Capt and one for FO. Both linked - they're not like "AP1" & "AP2" :-P

 

There are physically 2 A/P buttons, and while they do both engage an autopilot, their function isn't identical. Saying that there is only A/P button and that they're linked is misleading.

we all here know that there's to A/P buttons on MCP

my question is: how to change A/P in Command?

I would assume, like other boeing craft, you would switch the A/P in Command by simply using the other A/P switch when you are in a non-linked portion of flight (e.g. not an approach).  If the left seat was the PF and the right seat needs to take over, the left A/P button would be illuminated, you'd press the right A/P button, and the right button would then be illuminated while the left button's indicator light would be extinguished.

 

Is there some trickery beyond this?