Updating this thread the report is out:
http://kemhubri.dephub.go.id/knkt/ntsc_aviation/baru/Final%20Report%20PK-AXC.pdf
In contrast to early discussion bad weather had nothing to do with the crash.
Looks like something similar to the loss of Air France 447. A mechanical/computer fault which wasn’t a danger to airworthiness led to a professional flight crew stalling the aircraft and keeping it in that attitude all the way to the ground.
Near as I can gather from the accident report:
Over the course of about 15 minutes, there were three Master Caution alerts regarding the Rudder Travel Limiter Units (which help limit rudder movement to prevent overstress) where the pilots performed standard procedures to reset the system.
The aircraft continued to fly normally.
After the fourth Master Caution, the Captain decided to trip the circuit breaker to the Flight Augmentation Computer (FAC) to reset the rudder limiter. He had seen this done by ground maintenance. It was not a procedure recommended for inflight, although it could be done. However, after resetting the circuit breaker, he failed to reset the FAC On/Off switch on the panel. This left the autopilot, autothrust and FAC inoperative. The FAC handles the Yaw Damper, Rudder Trim, Rudder Travel Limit, and Flight Envelope.
With the autopilot and rudder control off, the aircraft suffered an upset. The First Officer (FO) (who was flying that leg) over controlled the roll and pulled the aircraft to 24 degrees nose up and into a stall.
The Captain moved his control stick to nose down and neutral but it doesn’t appear he ever noticed the position of the First Officer’s stick (full back), never used his override button to take control, and never took control of the aircraft from the FO.
The FO held the maximum nose up pitch for over 3 minutes, all the way to impact.
Do Boeing jets, by contrast, allow the captain to tell if the F/O is pulling back on the controls?
Boeing links the yokes. It would literally be a fight for control. Airbus uses joy sticks and whichever one is being used first becomes the dominant one and ignores the input of the other. What the Captain should have done was strike the FO’s hand away.
The Air France incident was a little different than you described. The loss of computer at that altitude meant the crew had a VERY short window of time to establish control of the plane. When that window closed it became a real problem.
Sounds problematic indeed. Can joysticks be linked the same way yokes are?
Or more normally, call “my plane!” to which FO would answer “your plane” and switch to monitoring systems. It would be a bit awkward to reach all the way across to the other controller stick.
As I said in the other thread, help me here, a known hardware malfunction that had been reported 23 times before, recurring ever more frequently… what the ever living heck would it take to send the plane to the shop and *pull *the damned thing?
But all the way down to, say, even 5,000 feet, wouldn’t Bonin theoretically pushing the stick forward have still solved everything?
The Airbus has an override button on the stick, I think whoever pushed it last gets control. Otherwise, with opposite commands, the control inputs are averaged out.
Not sure how you knock the FO’s hand off his flight stick, pretty sure they are on opposite sides of the cockpit in the Airbus.
It’s probably been discussed before, but I’d be curious to hear Doper pilot’s opinion on the Airbus vs. Boeing control layout. This is at least the second time the sidestick controller seems to be a contributing factor in a crash. I’m sure there are advantages in some phases of flight or they wouldn’t use them; but is it, as the British say, too clever by half? When the chips are down, alarms are going off, and you’re searching for answers, you need to know exactly what control inputs the plane is getting. With those big, mechanically-connected yokes, you know.
Maybe they should just do away with co-pilots on Scare buses.
Nah, best bet is to replace the copilot with a dog. The dog’s job will be to bite the pilot if he touches anything.
A friggin’ SOLDER joint?
On an airplane? A Big airplane?
I was once cautioned about buying a British car because they soldered the electrical connections, and, with vibration, the solder would cause the wire to break off the part (wires will flex; solder won’t).
This just keeps getting more and more bizarre - neither pilot knows what the other is doing with the stick and the wires are breaking at the joints.
I think the advantages are all related to weight and cost. Maybe some ergonomic advantages in that you don’t have a big ol’ control column getting in the way of your instrument panel.
So, he tripped the breaker to silence the annoying alarm.
I’m imagining my wife hearing a strange noise on the car, and responding by turning up the radio so she can’t hear it anymore :smack:
Also, remember the linked-yokes set-up is legacy design from when the controls and hydraulics were physically actuated through pistons and cables. You have a linkage going below the cockpit floor under the console, from the base of one yoke to the other. Boeing engineers decided to maintain that, Airbus went “clean sheet” with the sidestick controller.
Do you know another way to connect chips & other components to a PCB? They’re not talking about a splice in some data or power cable in the middle of the aircraft.
Oh, I know where the mechanism originated.
Is there any workplace that is as meticulously studied as the flight deck of an airliner? Considering the amount of effort that has gone into studying human factors, crew interaction, and instrument and interface design (and to great benefit, I believe) it seems odd that there are two such different schools of thought on the primary flight controller.
Yes, these days the primary flight controller is probably the autopilot. But when you gotta fly by hand, what’s the best way to do it?
There are people in cockpits that will stall an airplane. We know that. Let’s accept that.
How do we:
- keep these people out of cockpits
- transform them into people that won’t stall an airplane, or…
- develop something that stops them from stalling an airplane
Gettin’ real tired of people stalling airliners.
.
I took it that the break was was at the point a wire connected to a device. The kind of connection where a crimped connector is called for.
I’m guessing that they went with soldered connections to save weight.