Fly By Wire w/ bad IRS results in another Airbus upset

tomgoodman

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No heat

I just saw a bit on a crash of the X 31 in a flight test program. Seems someone forgot to connect the pitot heat, leading to airspeed readout loss at altitude.

Actually, that aircraft was using an experimental pitot system which was not designed to be heated.
They never expected ice to form in the extremely dry and clear conditions, but it did. One of our AFFTC A-37s (used for airspeed calibration tests) also had an unheated pitot system, and was restricted to VMC. We had no problems with it, but in hindsight, probably should have retrofitted a heated aux pitot system as a backup.
 

RP 04

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Thanks for pointing out my editing shortcomings :)

7 total computers, 2 of which are FACs, short for Flight Augmentation Computers. Turning those two off will disable a lot of the protections but still allow you to fly in Alternate Law.

I just saw a bit on a crash of the X 31 in a flight test program. Seems someone forgot to connect the pitot heat, leading to airspeed readout loss at altitude. Not a good thing in a FBW experimental bird. Test pilot punched out, plane went in flat spin free fall. Ouch!
It has been a while since I was on the 330/340, but I seem to remember we had 5 computers for the FBW, 3 PRI, and 2 SEC. I don't seem to recall anyting like as FAC's, or 7 computers.
 

Ralph Cramden

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It has been a while since I was on the 330/340, but I seem to remember we had 5 computers for the FBW, 3 PRI, and 2 SEC. I don't seem to recall anyting like as FAC's, or 7 computers.

A320 has 2 ELACs, 3 SECs & 2 FACs

The FAC computers are responsible for the majority of the protections.

It appears Airbus streamlined the computers on the 330/340. Not rated on that one...

Read an article on the new Falcon 7X. Not sure how many computers it has, but the Normal, Alternate and Direct laws looked pretty similar to the bus.
 

Golden Falcon

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A number of years ago I saw a video of an Airbus, I believe an A300, that departed a French airport and pitched up to +80 degrees uncommanded before recovering. It happened to at least 4 other jets as well, all recovering without serious damage or injuries. Did they not resolve the issue? Anyone have a link to the video? I prefer old school as well.

a300 IS old school bro
 

Wesb737fo

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How many 737's fell out of the sky due to a faulty rudder actuator? I'll stick to fly-by-wire, thanks.

You sound like a former Boeing guy who has found his way to the dark side.

I have never flown the bus, but I always seem to hear about those things doing stuff the pilot doesn't want them to do.
 

~~~^~~~

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Maybe zero.
Even the FAA is not certain.
Agreed. Packing the servo in dry ice, running it without lubricant and pumping superheated fluid into a sliding proportioning valve would make any valve stick.

But, I agreed with the NTSB's side of that debate. The design of a single valve, single rudder, with no rudder position indicator on the flight deck does not provide any redundancy and the airplane apparently is not controllable with a rudder hard over at flaps 1, 190KIAS.

Further, the yaw damper had a history of getting damaged by leaking hydraulic fluid and contributing to the problem.

I'm not a fan of either design, although the 737 appears to have been mostly fixed. My concern is the interest amongst engineers to get the pilot completely out of the airplane. In practice, all these systems eventually break and have faults. Pilots are always the best safety device on the airplane when these events occur.
 

Lear70

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I, also, am a bit spooked by FBW. I don't like not having control over my own destiny should I not like what the computers are telling me. I'm a pilot, not a fu*king computer nerd.

That said, get ready... the future IS FBW, as much as it sucks.

That's the direction Boeing is trying to go with ALL future designs.

That's how we're training the vast majority of the 300-400 hour wundermonkeys coming out of the puppy mills (the only source for pilots today). To play a giant computer game and not understand WHY something does what it does.

Look at Cramden. Look at his experience. Then look at the information he gave you. Now tell me one of those European low-time ab initio crews would have had that kind of in-depth knowledge of the aircraft to start THINKING outisde the QRH.

It's possible, but highly, HIGHLY unlikely.

It's possible the A/P disconnect did the trick, it's possible the QRH is what walked them through disconnecting things until they found the answer. Safety records are great and all, but the bottom line is that I don't want my life left up to a computer, thanks anyway.

;)

p.s. Hey 'Box, where you been? How the hell are ya'? :D
 
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Ralph Cramden

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I'll be the first to admit Fifi has a messed up FMS system, but for early 80's technology it is a pretty nice ride. I'll trade the FMS frustration for a roomy comfortable flight deck with a tray table to eat my meal on anyday.

Having the pleasure of a brief exposure to infra red HGS, graphical flight planning and synthetic vision during my stint in the Gulfstream 450/550, even the "high tech" Airbus is showing her age and needs updating.

For the "Boeing or I'm not going" crowd, what do you think of the 787's lack of anything but electrics? I see a lot of teething issues with that thing, and I'm not just talking composite structure damage tolerance in an airline environment.

BTW, we had standard items on the G450/550 that will be "future options" on the 787. I've been in the airline world long enough to know optional equipment means no airline will ever order the extra toys.

Too bad, as the IR HGS really gives one a fantastic situational awareness and greatly improves safety.
 

~~~^~~~

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True, if it costs more, the airlines will not order it. If they could equip our airplanes with a Directional Gyro and remote CDI and still get CATIII that is the approach they would take.

Ralph - I know very little about the all electric systems, but there have been multiple failures of Bus Power Control Units (I've had one) which take out every single electrical system on the airplane. In these designs the BPCU was the single point failure that would take down the rest of the busses as they either were isolated, or isolated themselves through their protective circuitry.

I doubt the 787 will have a single BPCU running the operation of the busses.
 

FR8mastr

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I don't think that the electrons are any better in the Airbus vs the Boeing. I think it comes down to design philosophy. Airbus engineers seem to think they know better than any pilot and do everything technology (and the public) will allow to take the pilots out of the loop as much as possible, no matter what the situation.
Boeing engineers have done the mostly the same thing with the big exception of, they left the little red button on the yoke. Because, there just might be some situation that they had not thought of, and just maybe the pilot will need to do something with this aircraft not in the programming.
Examples like really strong unpredictable crosswinds, or mountain waves, or maybe even a low pass the pilots messed up, and now they need to get out of dodge using just airmanship.
No matter what your thoughts are on the A vs B debate, they design philosophy between the two companies should be something that is clear.
 
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