Boeing 777 flight crew wrestle with airplane for control...

[typhoonpilot]

Does the ADIRU provide attitude and heading for the PFD and ND or does it have a seperate gyro for those?

The ADIRU provides Altitude, Airspeed, Attitude, Heading, and Position information to the PFD, ND, and Autopilot Flight Director System (AFDS).

labbats: There are three autopilot flight director computers in the 777. There is no way to specify which one gets turned on, they have there own logic and generally all three engage with either A/P engage switch.

When this article talks about the thrust levers moving forward as they approached the stall it doesn't really state that this is a protective feature of the aircraft. If speed decreases to near stick shaker activation, the autothrottle engages in the appropriate mode and advances thrust to maintain minimum maneuver speed or the speed set in the mode control panel speed window, whichever is greater.

It's an interesting incident and it appears there was a flaw that caused the intial pitch up. After that it gets a little fuzzy,

The bureau report released last Friday revealed the pilot in command disconnected the autopilot and lowered the plane's nose to prevent the stall but the aircraft's automatic throttle responded by increasing the power.
The pilot countered by pushing the thrust levers to the idle position but the aircraft pitched up again and climbed 2,000 feet.

This part here is particularly interesting. The pilot disconnected the autopilot and lowered the nose, okay both good moves. Then the throttles advance, which they will when you get near stick shaker. He brings the thrust levers to idle, possibly because the advancing power caused a pitch-up, but probably not a good idea if already near stick shaker. The last part is hard to analyze. If he is hand flying and the thrust levers are at idle, what made the aircraft pitch up again?

I'm waiting for a more detailed explanation.


Typhoonpilot

 

[dseagrav]

The ADIRU provides Altitude, Airspeed, Attitude, Heading, and Position information to the PFD, ND, and Autopilot Flight Director System (AFDS).

So if an ADIRU goes insane, the instruments would show it, right?

I'm waiting for a more detailed explanation.

Probably a good idea. ^_^

 

[Cpt. Underpants]

Seems an appropriate time to post this...

http://xs47.xs.to/pics/05382/777Nightmare.jpg

(Thinks...rich, coming from an Airbus pilot...but I can't resist the dig!)

 

[GravityHater]

Seems an appropriate time to post this...
http://xs47.xs.to/pics/05382/777Nightmare.jpg

And I had just changed my avatar two nights ago!

 

[Singlecoil]

Yes, I would. You can always disconnect it.

You might want to re-read that Alaska 261 accident report about troubleshooting broken airplanes. I'm not at all saying that is what caused that accident, but that is one of the recommendations that came out of the analysis of it. Treat every flight control problem as a potentially catastrophic one, get the airplane on the ground, and let somebody else figure out how to fix it.

 

[typhoonpilot]

So if an ADIRU goes insane, the instruments would show it, right?

One of the EICAS Caution messages is NAV ADIRU INERTIAL, which means that the ADIRU is not capable of providing valid attitude, position, heading, track, and groundspeed. I'm not sure if they got this Caution as it was an internal error that may not have triggered the Caution.


TP

 

[trip]

Yes, I would. You can always disconnect it

That is a very bad idea after a failure like the one described above. You might not be so lucky after the next go-round!

Let the Techs figure it out, on the ground.