|
Originally Posted by mrdeux
(Post 10563004)
Why the ADRs? If you turned the PRIMs off, you’d still get direct law, but you wouldn’t need to fall back to the BUSS?
|
Originally Posted by rjtjrt
(Post 10562953)
Morno. I admit I am completely unqualified, but I have always wondered if ‘what’s it doing now” goes through crew mind, then getting it into Alternate Law, or Direct Law if possible, would at least put pilot back in charge. I have been reluctant to ask this given my lack of real knowledge. The safety in turning off the ADR’s, is they’re reversible. So if you want to venture down the trouble shooting path and restore some normality to the system, it’s only the press of a button. The aircraft only needs 2 ADR’s to restore normal law. I’m not type rated on the 330, only the 320, but essentially they are mostly the same. Perhaps the 330 is just slightly different in its flight control computers (PRIMS?), being a bit newer than the 320. On the 320, and I assume it’s the same on the 330, Direct Law only occurs when you have selected gear down. So it’s normally only in those last few minutes of flight. And it’s a pain in the ass (in the sim at least) to fly, because the deflection of the flight controls is directly correlated to the control input from the side stick (it’s been a while since I’ve read this, so excuse me if it’s incorrect. Might be time to refresh my knowledge). Unlike Normal and Alternate Law, which still goes through the computers and deflects the controls an appropriate amount to meet the demand that we input through the side stick. So it will do it smoother and better. Unfortunately the side stick has zero connection to any flight control system, only a computer. So we have no feel at all. When everything is running swimmingly, the Airbus is easy and quite nice to fly. When it starts going bad, it’s a pain in the ass. Almost as if Airbus couldn’t work out a better way to deal with abnormal situations, so it’s like a bunch of problems and checklists stacked on top of one another. Unlike the apparently easier way that Boeing has done it, whereby you have a problem, you run a checklist that deals with the situation from start to finish. |
For instance the UNDUE MCAS ACTIVATION NNC.
|
Originally Posted by morno
(Post 10562933)
One of the things I’ve always kept in the back of my head after this and a few other incidents, as an absolute last resort, if the aircraft starts pitching itself around uncommanded, ADR 2&3 OFF, get the thing into alternate law. At least then the protections are turned off and I have a somewhat more controllable aircraft. Why don’t you look up first and check if one has an amber light illuminated before you rush in and turn two good ones off. 3 ADRs off results in a world of hurt/BUSS. And when you’re looking up switching 2&3 off the F/O loses his instruments. |
Originally Posted by Miles Long
(Post 10563165)
So what happens if you turn 2 and 3 off and it turns out number 1 is stuffed. Why don’t you look up first and check if one has an amber light illuminated before you rush in and turn two good ones off. 3 ADRs off results in a world of hurt/BUSS. And when you’re looking up switching 2&3 off the F/O loses his instruments. The problem is when none of the systems detect a fault, like in the QF72 case. But again, alternate law will stop the abrupt nose down pitching. As for the FO losing his instruments, big whoop. There’s still a set on my side. No Instruments on the FO side, or plunging into the ground, I know what I’d choose. Finally Miles, it’s a procedure that is an absolute last resort when nothing else is working and still lets you fly the aircraft. |
There's an old well worn adage by computer engineers that still holds since computers were invented and it goes like this:
"We put the bugs in the system." So why carp on about all the "what-if's"? The software is never perfect - only tested to a common standard. The plane is never perfect - only tested to a common standard. Just as well Cpt Sullivan being ex US Mil had seen imperfection in aircraft before and was the smoothing interface between a smoking hole in the ground and a safe return for all. And to think some people want to remove that filter out of the flying equation. |
Originally Posted by Blueskymine
(Post 10563013)
Prims receive their information from the ADRs (in a round about way) If she’s doing weird things, you’d want to isolate the corrupt data source. Your real aim is to stop the aircraft reacting to any dud data, and to do that you want a law change. Turning off the PRIMS will drop it to direct law, but all of the ADRs will still be available for you to try to resolve which is the bad source. My AB time is only on the 380, so I’m just extrapolating from it to the other types. |
Originally Posted by mrdeux
(Post 10563531)
You’ve got a fair chance of turning off the two good ones.
|
Originally Posted by Miles Long
(Post 10563165)
And when you’re looking up switching 2&3 off the F/O loses his instruments. |
Originally Posted by FlightDetent
(Post 10563602)
The smaller kites have only 3 ADRs. In case of two delivering good data (identical by necessity), it is the corrupt third that will get flagged. No need to deactivate two, a single one - the bad apple - would suffice.
Once you’ve got control over the situation and worked out the faulty one, it can be isolated and HAL can be brought back to the negotiating table. If you turn the two two good ones off you’ll work it out pretty quick. You’ve still got 5 mins of the ADR being off before it’s incapable of being reactivated. |
Originally Posted by cattletruck
(Post 10563241)
Just as well Cpt Sullivan being ex US Mil had seen imperfection in aircraft before and was the smoothing interface between a smoking hole in the ground and a safe return for all.
And to think some people want to remove that filter out of the flying equation. Not to take anything away from the crew on the day but the good training and level headedness that ensured a successful outcome were not specific to military trained pilots only. They are the good skills and habits that all good pilots develop and hone over the course of their careers. |
Originally Posted by Blueskymine
(Post 10564186)
The aim of the game is to turn two off ADRs for alternate law and thus preventing crazy flight protection inputs from HAL.
Once you’ve got control over the situation and worked out the faulty one, it can be isolated and HAL can be brought back to the negotiating table. If you turn the two good ones off you’ll work it out pretty quick. You’ve still got 5 mins of the ADR being off before it’s incapable of being reactivated. Think again, please. If you had two good ones (out of three) - which the previous post was so afraid of turning off - the HAL is happy an so is everyone onboard. :D The specific lifesaving trick discussed needs to be used only if TWO are wrong supplying incorrect but identical data, so the poor third correct bugger gets voted out of business. But then there's no fear of turning two good ones off, because you only had 1 to begin with. ;) |
| All times are GMT. The time now is 07:37. |
Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.