PBL and friends,
I'll quote PBL:
At the time of decision about including the "Taipei" warning, there were two known non-occurrences of X amongst, say, 30 million landings.
Rob21's intervention showed he is concerned with what is called the *correlation* between two events. These events are
These events are
* non-X: failure to retard all thrust levers to idle on landing
* Y: at least one thrust reverser locked out; or maybe
* Z: exactly one thrust reverser locked out.
Total size of sample space: 30 million
Non-X events: 2
Y events: 850,000
(Non-X and Y) events: 2
Sounds nice, but it has a glaring hole in it.
We're not interested in the "two
known non-occurrences of X", we're interested in the
real figure for "non-X".
We have no figures for the number of occasions where a (non-X and Y) event occurred as you have defined it, resulting in:
"No spoilers, no brakes"
"WTF?"
"Close the damn throttle, man!!"
...combined with decent weather and a nice long runway.
That would result in some red faces up front, but unlikely to result in a "known non-X event". It would still have been a (non-X and Y) event.
Add a few more of those, and your sample of non-X events is out of the window.
By the time I would start looking at, say, 10 of those non-X events in the Y sample space, I'm down to something like 10 to minus 5.
That's why I'm with RWA here.
Even his idea of sim flights might work...
Brief them carefully and extensively on having to use a
different procedure when one TR is locked out. Then throw a well-thought-out sample of sh!t at them (if they know what to expect, it won't work). With a bit of "luck", somebody may make the mistake, and we can ask him what happened.