Originally Posted by Posted by AlphaZuluRomeo
What means "safe conduct of the flight is affected" is, IMO, where the "problem" lies...
Fully agree with you, AZR. This condition seems to have been introduced and incorporated into the memorized drill portion of the UAS response, around 2006.
In its "
Unreliable Speeds; Latest Improvements" document from
September, 2006, it is indicated that the memory drill qualifying condition, "Safe Conduct of the Flight Affected?" will be "Defined in Training". But the guidance remains, if the safety of the flight is not affected, first step is to level off and troubleshoot. Prior to 2006 the drill had "Immediate Actions" and then "Immediate Pitch and Thrust Guidance" and then a "When Flight Path Stabilized" section which required the Probe Heat to be put ON and "Attitude/Thrust - Adjust".
The December, 2007 edition, (#5), of Airbus' "Safety First" an article entitled "Unreliable Speed" was published. The article is quite thorough and well-written, making clear many points. It states, in part:
Originally Posted by Airbus - Safety First #5, Dec 2007
1) If the safe conduct of the flight is affected, APPLY THE MEMORY ITEMS, i.e. fly a pitch with TOGA or CLB thrust,
2) If the safe conduct of the flight is not affected, or once the memory items have been applied, LEVEL OFF, if necessary, and start TROUBLESHOOTING,
3) If the affected ADR can be identified, fly with the remaining ADR.
4) If the affected ADR cannot be identified or all airspeed indications remain unreliable, FLY WITH PITCH/THRUST REFERENCES
The question, as always when such changes occur and the distribution and incorporation of infomation is involved is, how are these changes incorporated into training by airlines operating Airbus equipment? As with most editorial changes, these changes were ordinary in the sense that most changes in procedures, SOPs, checklists and so on go through a pretty thorough vetting process even at the airline and are then published, incorporated into SOPs and training scripts and regimes, all of which take time to make their way to flight crews.
Here again, as this is the way almost all changes to SOPs work, we have to be mindful of hindsight bias. We can see now, that there were at the time of these changes, already UAS & ADR events occurring. The 2006 documents speak to awareness and addressing of the issues.
According to BEA IR#2 Appendix 7, "
List of events on A330/A340 attributable to the blocking of at least two Pitot probes with ice, identified by Airbus as of 3 November 2009" there were ten UAS events prior to 2007. So the information would have been "out there".
Since most crews appeared to have kept the aircraft level while troubleshooting, (we don't know this for certain but it appears so), it would be interesting though likely difficult to determine given the passage of time, if crews who had one of the listed UAS events had had either training in the changed procedure or were at least aware of the changes and knew how to do the updated drill.