Turbine D;
No worries, I understood what you were explaining and am somewhat familiar with Six Sigma - it was actually quite a good explanation, thank you.
In response to your important comment:
Now pertaining the A-330, there is a memory list for pilots to memorize regarding the occurrence of unreliable airspeed. It defines what a pilot should do if UAS is encountered and as I recall, it emphasizes low altitude critical situations, takeoffs and landings while also mentioning altitudes above 20k feet. It does not mention the words "at cruise" or "high mach". Now in cases of UAS at cruise and high mach, most pilots have figured it out, what to do to prevent LOC, but more recently, not all have done so. Would an improvement to the memory list to include what to do "at cruise" help future situations that might occur?
Yes, I think so - we're thinking along the same lines and in fact I worked on a design change of this drill last summer, (July, 2011). I have always considered the Unreliable Airspeed memorized drill poorly designed and confusing primarily for those circumstances in which I considered the safety of the flight "not impacted". Here is why:
The UAS memorized drill has a primary decision point, "
If the Safe Conduct of the Flight is Impacted", which requires that the crew decide "are we safe or unsafe?" In my view, this primary decision point which is intended to lead the crew into one drill or another, is too imprecise. The "one way or the other" is either to pitch up to certain degrees and set power to TOGA or CLB, or to not execute these memory items and instead "Level Off > Troubleshoot > QRH Pitch and Power tables". In other words,
don't pitch up. To my knowledge this crew never experienced this kind or level of training in their recent sim sessions, (and I can categorically say that I have never even encountered the UAS drill in all my Airbus A320/A330/A340 initial or recurrent ground or sim training.)
In a recent and much more detailed description of this drill than I have seen before, a note in the PPT indicates that the meaning of safe conduct will be defined in training. Then it goes on to explain how the drill is done. The presentation is dated 2006.
In other words, "when" the safety of the flight "is/is not" impacted has a definite meaning but this is not defined in any SOP/QRH/FCTM with which I am familiar.
But this isn't the important point. The important point is, no matter what phase of flight, the primary "bifurcation" point...the point where the memorized drill launches one way or the other, applies to all altitudes and all phases of flight - climb, cruise, descent...and, as you have suggested...there is no defining of "cruise", or "above FL200", etc etc.
So I thought why not base the primary "bifurcation" or decision point on phase of flight rather than the very subjective and individual assessment, which defines the "safe conduct of the flight"?
Clearly, the safe conduct of the flight is impacted at/during the takeoff phase...the closer to the ground, the higher the risk. This is a direct result of the two loss of airspeed & altitude information accidents we are now familiar with, the Birgenair and Aeroperu B757 accidents, (which, for others, please see).
So immediate pitch and power numbers need to be memorized and instantly applied until "at/above MSA or Circuit Altitude" and then the aircraft is to be leveled off for troubleshooting. Leveling off includeds selecting the GPS Altitude on the FMC/MCDU, and getting out the QRH pitch and power tables.
In the memorized drill, there are three sub-decision points depending upon where the airplane is in the takeoff/early climbout phase.
For information purposes, the Airbus thrust reduction altitude in force at the time was 1500ft
AGL. I believe it has since been changed to 1000ft AGL, but no matter.
The three conditions of the memorized portion of the drill (and after the decision is made that the "
safe conduct of the flight is impacted") state:
Pitch/Thrust:
- Below THRUST REDuction ALTitude..................15
°/TOGA
- Above THRUST RED ALT and Below FL100........10°/CLB
- Above THRUST RED ALT and Above FL100.........5°/CLB
The FCTMs I've seen further confuse the issue by saying first of all, if you've chosen 5deg of pitch because you're above FL100, (thinking the "safe conduct of the flight is impacted"), then very quickly get out the tables to ensure speed stability, (specifically, the overspeed sitution is mentioned...nothing is said of the opposite problem...loss of speed if pitched up too much). But then the FCTMs state that if the safe conduct of the flight is NOT impacted, the crew will not apply the memorized items but get out the QRH pitch and power tables while maintaining stable flight.
So the potential for applying the wrong procedure is there, but the potential is largely molified by the actions described in the QRH and as such reduce risk providing the crew gets out the tables quickly and establishes stable, level flight.
The difficulty comes when the subjective assessment of the "safe conduct" of flight is made...some would consider the loss of all speed indications a clear and present danger to the flight and launch into the drill. Others would light up a pipe, (metaphorically speaking...to indicate a calm, measured approach!
) and maintain level flight while the other pilot got out the numbers. Why not base the decision for subsequent actions on the phase of flight, where there is an emergency, and where there probably isn't, (as in cruise flight)?
It made sense to divide the phases simply...into "Takeoff or Below MSA" and "Above MSA in Climb/Cruise/Descent.
For the former, to the usual memorized items. For the latter, level off for troubleshooting, set the GPS Altitude and groundspeed on the MCDUs and get out the QRH pitch and thrust tables.