reply to post by turbofan
I AM sorry, Tino, but you're still wrong.
I mean, you as a layperson, can read ALL of the Boeing 757 manuals you may wish, but you will NOT have the practical knowledge and experience I have,
NOR can I convey everything I know in this forum.
OK, in ONE aspect you are correct, in THAT....any given location of ANY gear, while in transit, is not recorded....ONLY its position, whether "down
and locked" or "up and locked"....in-between states are NOT measured.
Staying on this aspect (only ONE of many, if you will recall, that I supposed in order to refute your original contention) there are STILL a multitude
of parameters that must be agreed to, in order to supply the "logic" for the lights, as displayed to the pilots. It is FAR more than a simple
"yes/no" logic switch.....
The landing gear logic circuts are satisfied, of course, IF the sequence behaves in acordance with its design and in the time parameters built in
(although the time sequence is irrelevant, really, except to offer the REASON for any discontinuity, should it be triggered).
IF YOU look deeper into the landing gear system, for example, you will find out many, many things.
IF there is a complete loss of 'normal' hydraulics, for instance, the gear is designed to "free-fall" into the down and locked postion (please
note the way the nose gear is designed....it retracts upwards and FOREWORDS, thus in "free-fall" mode it will have air resistance to assist its
positioning. into the "down and locked" position. The Main Gear simply use gravity, because they are massive enough....)
The REASON we have QRH procedures, for the unlikely event of a failed gear, whether a Main Gear or Nose Gear, is because while they are designed to
free-fall, that assumes NO mechanical jamming, and that HAS been known to happen, in very few cases...(not that I'm aware opf in the B-757/767, but
in other Boeings, wiht similar design issues...)
Again, in the event of loss of "normal" hydraulics, we have redundant systems (please see the schematics) to release, via hydraulics, the uplocks,
to allow what I described above.
Note, also, that we ARE AWARE (and it is incorporated in our QRH) that in the event of certain hydraulic falure procedures, the "DOORS" light,
wihtthe EICAS alerts, will remain on, BECAUSE hydraulics are required to close the main gear doors...
Trust me, I have a type rating on these airplanes, AND I am well trained in their operations....
The complexities involved in JUST this one, of very many, sub-systems goes to prove that the notion of somehow "faking" the FDR, by use of a
simulator, is just a load of nonsense...
As I've mentioned, before, the computer languages alone are not compatible.
I challenge anyone to prove THAT wrong....
[edit on 24 January 2010 by weedwhacker]