Welcome to Flightinfo.com

  • Register now and join the discussion
  • Friendliest aviation Ccmmunity on the web
  • Modern site for PC's, Phones, Tablets - no 3rd party apps required
  • Ask questions, help others, promote aviation
  • Share the passion for aviation
  • Invite everyone to Flightinfo.com and let's have fun

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

Welcome to Flightinfo.com

  • Register now and join the discussion
  • Modern secure site, no 3rd party apps required
  • Invite your friends
  • Share the passion of aviation
  • Friendliest aviation community on the web
labbats said:
Time out, fuzzy.

He engaged each autopilot seperately to find the malfunctioning one. It's a common phenomenon. I know that per our Ops Specs, we check each channel of a failed flight control system as well to isolate the problem and avoid any confusion on the current situation and unavaoidable write up and FAA report.

:eek: You're saying that after a violent pitch-up and approach to stall with the A/P, you'd try it again so that you'd have a more concise write-up for the MX folks? If my A/P shat on me like theirs apparently did, there's no way I'd re-engage it!
 
Yes, I would. You can always disconnect it.
 
viper548 said:
Do they have the latest version of NORTON installed?
It's probably those French bastard's from Airbus who stashed some of their software into the Boeing's computer!
 
You gotta wonder... being in the tech profession, when something deep goes wrong, you wonder how the hell computers manage to work at all given the complexity. Last night walking out of work after working on an intense prolem, my boss (ex-nasa space-ship guy) told me they once spent two years debugging a strange computer glitch on a certain interplanetary probe that was launced several years ago.. two separate computers had to both be executing a particular piece of software and the overlap had to be within a few picoseconds of each other; the event caused some electrical noise which created a glitch. The complexity of a modern airliner is probably not far off from that of spacecraft; I think I'm more comfortable riding around in something that has real control cables going to the actuators!
 
dseagrav said:
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
 
typhoonpilot said:
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. ^_^
 
labbats said:
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.
 

Latest resources

Back
Top