mop, your scenario (e.g. a single ASI jumps to 0) is not an unreliable airspeed scenario, it is an airspeed indicator failure. In this case (assuming the remaining two airspeed indicators are in agreement), I would not even commence the unreliable airspeed checklist.
However, you have mentioned the word "confusion" which is the main theme behind my opinion on this subject, which obviously differs from some other posters.
Many accidents occur due to confusion on the flight deck. Yes, there is always a sequence of events or errors that leads to the confusion (contributing factors), but it is often the confusion that is the final cause of the aircraft crashing.
Air France, Birgenair, AeroPeru and Air Asia all crashed with confusion on the flight deck. In particular, Air France and Air Asia both crashed with one pilot confused about what the other pilot was doing. In the case of Birgenair, it appeared that both co-pilots understood the situation but did not intervene out of deference to the Captain, who unfortunately was very confused.
Human factors are incredibly important in preventing non-normal situations from turning into aircraft accidents. Confusion can be a real threat - and the best way to resolve the confusion is good teamwork. Good teamwork requires a shared mental model.
In normal operations we create a shared mental model by using SOP's and briefings. However in non-normal operations, we haven't done a briefing (with the exception of engine-failure during takeoff), so the shared mental model comes from the QRH.
Now, with an unreliable airspeed, the potential for confusion is extremely high. Pilots really struggle to ignore instruments they have spent thousands of hours trusting. It is highly likely that contradictory indications are occurring (eg overspeed and underspeed indications or warnings). Pilot A will be looking at different information from Pilot B, and may have a different idea of what is wrong with the aircraft.
Now if Pilot A decides to use his airmanship (Boeing actually calls it "good judgement" in the QRH), and decides to pull an attitude and thrust out of his head instead of commencing the non-normal checklist, how is this going to affect Pilot B? How is this going to contribute to good teamwork? How is this going to resolve the confusion?
Pilot A has successfully added to the confusion because Pilot B does not know that Pilot A is an ace and has a photographic memory of all the attitudes and thrusts in the QRH performance in-flight section.
In short, it is not superior flying skill that is going to save this aircraft. It is superior teamwork.
Potential traffic in tight RVSM airspace needs to take a distance second in your consideration even if it does give you a headache. You now have an emergency. That means you now "own" the airspace. A quick mayday call to ATC telling them that you are unable to maintain altitude will suffice and they will get everyone else the hell out of your way.
I note all the opinions above, but I stand by mine. In my "good judgement", ignoring the checklist has no up-side, but a considerable down-side.
Last edited by Derfred; 23rd Dec 2016 at 04:31.