The aircraft rolled to the left and adopted an approximately 10º left-wing-low attitude, without any flight control input from the crew. The flight crew reported that the aircraft did not seem to respond as expected to their control inputs and shuddered and jolted repeatedly.
First, a thought: if you make a control input and the aircraft does not respond as commanded, you are by definition in "out of control" flight ... so technically, the crew in this incident had a short excursion into "out of control" flight.
Curious regarding reaction from the pilots to this uncommanded control input from the robot.
When I was flying fleet helicopters with complex AFCS, the typical immediate action response (NATOPS BOLD FACE etc) was that uncommanded flight control inputs required immediate disconnect of AFCS, (don't consult the checklist, do it!). IF SAS or Boost was giving you spurious input, (AFCS being off, and the heirarchy being what it was) dump them as well until spurious input ceased.
As I read this report, the crew's reaction was similar but different. It appears that it took them a while to work through the "what's it trying to do now" and I gather that the intermittent nature of the fault drove that.
Am I following correctly? (Nice to be at 36K and have the luxury of time to work through a problem).
Unhooked - I recall hearing about an incident with a A340 out of MRU where the AOA vane was damaged in the stand and went unnoticed or unreported. ... I think the fast thinking commander switched off some of the PRIM's & SEC's (primary and secondary flight computers) and managed to return in direct law.
Fly the plane ... and disable any systems interfering with your flying the plane. Important point on that is that you really have to know your systems to ensure you know what does what ...
wiley - Complex systems fail in complex and often unanticipated ways.
Which is part of the problem of the "magic airplane" design philosophy.
You create X problems when you use robots to solve Y other problems. The only defense the crew have is expert and in depth system knowledge, and a robust continuum of training.
Clandestino - ... that Airbus is crash-proof and can cope with less skilled pilot than standard is misperception, promulgation of which is the fault of Airbus propaganda department, not the fellows who designed the Airbi.
Woe to the airline whose training department takes this sales pitch to be true.
Compared with a couple of decades ago, modern pilot has replaced: pilot, flight engineer, radio operator and navigator. Creating better and easier to operate systems was meant to decrease workload. It succeeded yet the intention was not to make life in cockpit easier: it was to reduce workforce as much as possible. It is all fine and well as long our electronic little helpers do their work. When they pack up, you have two people doing the job that was historically split between 4 to 6
Good point. Made a similar observation a few days ago, how complex aircraft and reduce crew actually up the requirements and demands on the crew. I found when doing crew training that any two man crew can eventually reach task saturation. (I had an evil reputation as a sim instructor, I confess!
I liked to find crews' limits with multiple system malfunctions / emergencies ... unscripted.)
stev - A lot of the incidents of recent times have come from lack of knowledge of what the system is doing. Much of what Airbus tried to eliminate in the making of the A320 has been taken care of in the major developments of teaching of the modern elements of CRM. Leaving it to the computer may not be ideal.
Rananim seems to have a sound philosophy on that one.
rananim - I believethe airbus peole were well-intentioned and produced a landmark machine but the over-confidence was sickening...I like it this way.Monitor me,warn me but give me control.always.
Next thing you know, one breaks up over new york and the pilot is blamed for using the rudder. A memo comes out telling me not to use the rudder if I can help it!
Which brings us back to the incident in question.
From the report, it seems the rudder was being commanded (by other than a pilot) to do something that it should not have been doing. I will guess that perhaps -- and perhaps not -- the limitations in rudder control defelction were being respected by the robot (or not???) even though the robot, thanks to some dirty trons, was moving the rudder when it shouldn't. Different logic/control loops?
That is my layman's way of trying to decipher which protections may or may not have remained when one (of many channels) in the automatic flight control system went wrong.
It looks like the crew approached this malfunction in a rational, unhurried, and professional manner and got the bird to where it needed to be: on the ground where the electron chasing magicians would investigate and remedy the fault.
My surmise is that the robot will find another way to challenge a cockpit crew in unexpected ways in the not to distant future.
May it not happen close to the ground.