In their minds they had a suspect flight control system and did not know why.
Capt Kremin,
Since when does a flight control system problem announce itself via:
1. False stall warnings;
2. False overspeed warnings;
3. Erroneous altitude and airspeed indications;
4. Inertial reference system (IR) fault messages?
... a highly suspect flight control system and no clue as to the real culprit.
“No clue”? At the onset of the accident, before the first pitch-down, the captain’s PFD began giving erroneous and erratic airspeed and altitude indications. But the indications on the 2nd pilot’s PFD and standby instruments were normal and without fault.
Where does the captain’s PFD get that data from? The #1 ADIRU.
There were also false stall and false overspeed warnings. These four things all came from the #1 ADIRU.
One of the initial ECAM warning messages indicated a fault with the #1 IR (inertial reference system). That IR “component” is built into the #1 ADIRU.
How can you possibly say they had “no clue”?
Remember that all of this unfolded in the two minutes before anything happened on the flight controls.
There were more clues pointing to the #1 ADIRU, but these were less obvious, and I will concede that the systems knowledge of the average pilot is such that they probably would not have made the connection. Those were:
1.ECAM message indicating a fault with the EGPWS;
2.ECAM message indicating a fault with the “autobrakes”.
Should the pilots have had more of “a clue” as to where the problem was coming from? Is it reasonable to have expected their systems knowledge and diagnosis abilities to be better?
Why didn’t the ATSB ask these questions? Would the answers have been too uncomfortable? I believe the ATSB/BASI of old would have asked those questions.
As a youngster I would read, from cover to cover, every copy of Aviation Safety Digest I could get my hands on. There were several messages it would hammer the reader with, every chance it got. One of those messages was “know your aircraft and know its systems”.
If the pilots had recognised that #1 ADIRU was suspect and switched it off then nobody would have been injured and the flight would have continued uneventfully to Perth.
The two pilots on the flight deck had two calm, stress-free minutes to figure out what was going on. It appears they were unable to, as, at the moment they were summoning the third pilot for assistance, the first pitch-down occurred.
Was this a difficult fault to diagnose? It is always easy in hindsight to pass judgement about a crew’s actions but I believe this WAS an easy fault, and that many of the world’s Airbus pilots would have picked it.
In fact, of all the un-annunciated faults that these aircraft could present, this one would have to rank amongst the easiest to diagnose and action.
Are the pilots of these highly automated aircraft becoming dependent on the aircraft’s own warning and messaging systems for diagnosis of faults? Are they already fully dependent? And is this mindset encouraged by Qantas? What about other airlines?
It would appear that the industry expects nothing more from a pilot than the ability to read an ECAM message and respond with the appropriate checklist. This ATSB investigator appears to be of this view, as does Capt Kremin.
It also appears the industry is happy to accept that pilots of these aircraft can easily become confused. The following quote is from the report. The investigator is NOT quoting one of the pilots. These are his own words:
After the first pitch-down, the flight crew were presented with a situation that was even more confusing ...
The pilots of Air France 447 were confused too. A minor fault affecting the airspeed readings caused their autopilot to disconnect. That aircraft was in stormy weather, over the middle of the Atlantic, in the middle of the night. The aircraft was flown into a stall, where it remained for the 3 minutes it took to fall to the ocean.
There was over 20,000 hours of combined flight experience on the flight deck of the Air France aircraft but the result was no different to what could have been expected had 10 year-olds been at the controls.
There are some hard questions to be asked about the man/machine interface in these highly automated aircraft.
The ATSB had a golden opportunity to ask those questions but ducked it in favour of a report that would upset as few people as possible. This investigation and report is a blight on the once proud history of the BASI/ATSB.
Airbus has not sought to criticise them and holds them blameless.
This accident was highly embarrassing to Airbus. It was their software that thought the pitch-downs were a good idea. The much vaunted protections offered by their FBW aircraft are about protecting the aircraft from pilots, but this accident has shown that an Airbus aircraft needs protection from itself (!)
Airbus would want this accident swept under the carpet.
Qantas had absolutely no problem with the response of this crew ...
Qantas were not at fault but would nevertheless, like Airbus, want the attention to die down as quickly as possible.
Last edited by FGD135; 4th Jan 2012 at 04:15.
Reason: Changed 10 minutes to 3 minutes