PBL, my apologies, the design engineer is American, not Dutch (happens when you research and post in a hurry). His name is Jef Raskin (now deceased) and he was a software design engineer.
I find I agree with the design rules as they were stated by Raskin. The personal experience of 4poleholer in post #412 and the following 2 accidents, has led me to believe there's a design issue.
2004 Taipei accident
http://www.asc.gov.tw/acd_files/189-c1contupload.pdf
1998 Philippines accident
http://aviation-safety.net/database/...?id=19980322-0
All 3 of these incidents are identical in failure mode. With one TR inop per MEL, upon landing, the TL of the unaffected engine is pulled back into reverse, but the other TL is left in the climb power detent. All three experienced no spoilers and asymmetric thrust (one engine in reverse and one at climb power).
You have to ask yourself a few questions about this.
Q1. Why would any pilot leave the engine with the TR inop in the climb power detent after touchdown? To me, this is THE major question of this accident.
Q2. How could any pilot NOT pull all power back after touchdown, since he must stop before the end of the runway?
Q3. Why does Airbus have to send out notifications to remind pilots to pull ALL thrust levers back to idle upon touchdown, when EVERY pilot should instinctively know to do this?
A1. I believe the answer lies with the mode (or state) change that occurs at touchdown with the A320 throttle system. When looking at the CVR transcript and FDR data, it's clear the pilots were concerned about stopping before the end of the runway in the present conditions, just prior to touchdown. In anticipation of the need to apply maximum braking, a pilot moved the TL of ENG1 back to idle just prior to touchdown. In doing so, he left the TL of ENG2 (with TR inop) in the climb power detent, which probably seemed to be the correct setting for TL ENG2 at that moment, because the AT was engaged at that moment. However, having started this TL movement early, the pilot is now setup to miss the state change when WOW occurs (and AT disengages), because of the intense focus on deploying the TR of ENG1 as quickly as possible. When WOW occurred and the AT disengaged (though probably disengaged when TL ENG1 was retarded), the Climb Power setting of TL ENG2 now meant climb power. To me, both pilots simply missed the state change, as Raskin said would happen in Rule 1a.
A2. I think the answer to this question lies in the fact that there's a mental habituating disconnect between throttle position and engine power on the A320. If throttle position does not always equate to engine power, then it’s possible to have a confused moment under pressure, and to forget the current mode. In throttle system design, TL position and power either ALWAYS equate to each other (single mode, which is habituate and forget) or they do not (multimode, which cannot be fully habituated and must be mentally processed at times). When flying Auto throttle to touchdown, on approach the AT is reducing power for the landing (when TL position does not equate to power and the AT is performing the power reduction). But at touchdown, the pilot has to take over (when TL position suddenly does equate to power and the pilot has to perform the remaining power reduction). I personally think the TL position mode change is the more significant state change at touchdown, as all pilots who fly auto throttle know they have to take over power reduction after touchdown.
A3. The answer to this question should be obvious by now.