Re: Interresting thread in comp.lang.eiffel

["Ken Garlington" <Ken.Garlington@computer.org>]

"Robert I. Eachus" <rieachus@earthlink.net> wrote in message
news:397A5CB4.AF5F6B8A@earthlink.net...
> But they were not on contract for the Ariane
> 5, they were
> contracted to develop a new IRS for the Ariane 4!

Bob, could you cite a reference for this? It seems only fair, given that
I've provided references that describe Sextant as an Ariane *5*
subcontractor, as well as part of Ariane 4?

If you've got better information than Aviation Leak, fine -- they've
certainly made mistakes before -- but could you at least give something that
says your information is better?

> the development of the new IRS was officially part of
> the Ariane 4
> project.

Again, if you could cite a contract reference -- anything -- that
contradicts the AW&ST claim that "Ariane 5's IRU is an improved version of
Ariane 4's, and the older Ariane 4 is now also being equipped with the
version modernized *for Ariane 5*"

> > The gains changed abruptly when the aircraft transitioned from
> > takeoff-and-landing to up-and-away mode. This produced a sudden
transient,
> > triggering the start of the PIO. The transition now occurs more
gradually.
>
>    That fixes the primary cause, but not the actual failure mode.  Does
> the stick now
> have tactile feedback?

No -- you don't often get significant tactile feedback from a force-sensor
side stick connected to a FBW system, such as that on the F-16 or F-22. (In
fact, the original F-16 stick didn't move at all!) There are "active" sticks
and throttles, but they tend to be more complicated and therefore more
expensive/less reliable than their passive counterparts.

IIRC, some larger FBW aircraft such as the upgraded F-111 and Airbus series
do have stick shakers, but it's generated by the FBW system when the
aircraft gets close to the computed envelope limit. That kind of feedback
doesn't help much if you get into a PIO loop.