Stop your fairy tell here Safety Concerns, or show me the thousands reports of pilots who could not be saved by lack of protections.

The Hudson outcome has absolutely nothing to do with the aircraft type, but everything with the decision making and the ability.
And ask Sullenberger what he thinks about his 320 that refused to flare the way he wanted to ...

OK...thanks. Don't know why it would show disabled. Only the e-mail one is. No big deal.


I think we're both on pretty much the same track. Nice being out of all this mess, isn't it ?!?!

I see, a "conspiracy theorist". You are spouting off on something on which you confessedly don't know anything, and you want to doubt even the experts.

My view is derived not only from the accident report but also from someone who works with the engine manufacturer closely, who is an expert on critical SW, and who has been a respected and trusted colleague of mine for two decades.

I don't know whether that's enough for you. But it's enough for me. And I'm the expert.

PBL

CONF iture
 

"ask Sullenberger what he thinks about his 320 that refused to flare the way he wanted to ..."
You're too subtle for me, but maybe that A320 knew what was the best amount of flare.

DC-ATE-Crunch: I also took cars apart and understood what they were made of.
Now I can't even see what's in there... But they're much better cars. And safer.

Imagine steel cables running to the far corners of an A380. Firstly they're so heavy that it wouldn't perform.
Secondly can you honestly say all on board the QF machine would be alive today if Airbus used 1950's design standards?

What part of this text from the accident report don't you understand.

As there were no safety recommendations relating to the performance envelope software; work it out for yourself conf iture what is being said here.

Once you have you will realise that criticising FBW has more to do with misplaced ego than any design deficiency.

Sully could have landed any Boeing with no automation in the Hudson with no problem. Airbus had nothing to do with his success. He was a very competent pilot and could have landed any type of aircraft in the Hudson with no automatic help. I think most of us would hope we could too. We just don't need the opportunity to display it like he did.

Safety Concerns
You would be welcome to quote me if I have ever criticized FBW … but do you only understand the difference between FBW and protections ?

NTSB report on US1549
Maybe there is a difference between maintaining the flight envelope protections alive and actually use it ... what do you think ?.
Where in the report, is it said that the protections took over to prevent the 'green' Sullenberger to stall ... Please quote !?

More on the Hudson Here
To be in DIRECT LAW would have helped Sully, but once again, do you only understand what's the difference between DIRECT and NORMAL ... and yes, both are still FBW.


And please, don’t forget to quote the thousands reports that would support your earlier statement …

Well, when they start making cars FBW, I'll quit driving too !

As to the 380.....there really isn't a need for that monster anyway. It's just one manufacturer trying to outdo the other IMHO.

The protections are part and parcel of the FBW system if we're talking about the traditional separation between FBW, which relates to computer-assisted control, and FMS, which relates to a computer controlling the aircraft directly and is in effect simply the latest generation of autopilot.

Stability protection was the whole purpose behind the first generations of FBW anyway, as the military aircraft in which it was installed were inherently unstable and needed constant computer correction to maintain flight.

I don't think there's a single incident where the protections have caused a hull loss - at least not when there hasn't been a major malfunction.

Er, no-one was suggesting that... you made that one up on your own.

Disagree strongly. Sullenberger had no need to place the aircraft in an attitude outside the protection boundaries, and I believe the protections were a useful backstop - a last line of defence against, say, a gust strong enough to cause the aircraft to bank - in much the same way as they've kept the wings level in earlier incidents.

In fact at no point has Sullenberger even hinted that the aircraft did anything other than what he asked of it (besides the obvious double engine failure due to birdstrike) and the link you provide only goes to your supposition in an earlier thread - and like it or not, the fact that you have an axe to grind with Airbus is well known.

Anyway, as I understand it the protections allow for up to 60 degrees of bank if the pilot commands it - much more and you risk a spiral dive.

DC-ATE
 

Merc's Distronic+ cannot be turned off and has the last word in a number of situations. Although not full FBW, I am afraid you may have to quit driving somewhere in the future...

d3

Because properly flaring an aircraft is to "place it in an attitude outside the protection boundaries" ???
Strange definition for a flare ...

"Ex-spurt"
 

PBL,
Well, even though I don't think it's a conspiracy, I noticed that most people who go around calling themselves "experts" are anything but that. :} Witness the so-called "Aviation Experts" touted in the popular press who frequently cannot answer basic questions about the accident aircraft. For instance, "expert", it sounds like you're not even sure which programing language is used on the trent FADEC system. Since you provided no links or quotes at all to back up your assersion that the investigative process is infallible, it appears to me you may making nothing but an:

PBL, please state your background that qualifies you as an expert on the trent FADEC system, and if not that, exactly what kind of expert are you claiming to be? It has nothing to do with conspiracies. Accident investigations are inherently political by their very nature. Ambitious human beings write the reports. You made a claim that we should just trust authority that the FADEC did it's job, and to give your claim credibility I need to know how many years working on aerospace software you have. :)

That's a fair question isn't it?

CC

Captain-Crunch,

you are welcome to question my credentials. You are also welcome to check them out. My identity is no secret.

I guess I could mention a couple of recent developments that don't yet appear in the public record. Our textbook on computer-related system safety is almost finished in draft, and will be published next year by Springer Verlag. And I have recently been invited to join the German standards committee responsible for the functional safety of systems involving programmable electronic components in order specifically to develop guidelines for the application of the international standard IEC 61508 to critical-software development in Germany. This standard governs all applications other than aerospace and medical devices (there are also specific derived standards for other domains such as process control and railway systems). I am on the international maintenance team for the software part of IEC 61508.

Is that the kind of thing that would enable a layman such as yourself to agree that I am expert?

As for my colleague who vouched for the accuracy of the FADEC judgement in the BA038 report, you are welcome to guess who he might be, but will get no confirmation from me.

PBL

Do you drive a car with Electronic Stability Protection (ESP)? Most new European cars have it. So do remember not to rent a car if you visit Europe.

PBL

Yes, but please don't forget that Hamburg came very close!

PBL

Very Impressive PBL,

Sorry to doubt your good word, but we get instant experts coming out the ears around here as I'm sure you can appreciate.

Although I was not asking for your identity, it appears your group is comprised of Ph.D's and has experience in accident investigation. I picked up a Computer Studies A.S. degree and studied for a time at an Aviation University and took courses in Aviation Safety and Accident Investigation so this sort of thing interests me. I later assisted in the preliminary investigations of a couple of accidents in our pilot union and my flight safety report (flameout in a typhoon) was used in the clearing of one crew of blame for an overrun accident. I'm not familiar with the language standard you maintain, but it sounds very interesting.

I suspect I could comprehend some of the FADEC architecture if I had access to it; but I'm sure it's proprietary. (not the physical code, but flowcharts would be interesting.) It would be interesting to know how the sw handles all fuel temp probes iced up. On AF447 it was clear to us on that thread that no one considered the possibility of all three airspeed probes and all static probes icing up at the same time. Rather than exercising a flight with unreliable airspeed strategy: N1 and deck angle, which pilots of most jets would employ, the software apparently biased out most of the backup systems according to the ACARS transmissions. In other words, the autopilot and auto throttle were incapable of operating with no pitot static system and abruptly dropped out throwing it all in the lap of the pilot on a dark and stormy night with partial panel.

This seems like a serious software design oversight imho, at least from a pilot's perspective. Arguments that it was approved and certified by experts really mean little if you are a student of Aviation history as I am. All designs eventually crash with any appreciable time in service.

If you ask me, adding more and more complexity to this automation monster we have created and keeping everything in extreme secrecy is what really does the industry a disservice imho.

KISS baby, KISS! (keep it sim...)

And I think it's best to realize that this is after all, a pilot's rumour network, not a tabloid for the public to read. Right? :)

Best Regards,

CC

Captain Crunch,

thank you for your gracious reply.

You are right about design and code being proprietary. Your suggestion (flow charts, which no one uses any more as far as I know) concerns design. Then there is the coding. General industry knowledge (not of RR in particular; I have no specific knowledge of the quality of their SW and do not wish to suggest that I have) suggests that in delivered safety-critical SW one can expect about 1 error in about 1000 lines of executable code (LOC). State of the art for the last few years appears to be about 1 error in 25,000 LOC; that has been achieved in well-documented products derived according to a very strict and well-proven analytical regimen during development. So in, say, 150,000 LOC one would not be surprised to find between 6 and 150 errors.

A distinguished colleague of mine proposes that all safety-critical software in any domain should be published, by law, so that anyone is enabled to check and comment on the quality of the product. ( And of course to enable the usual army of computer-obsessives to find faults in it faster than the developer :) ) I think that proposal has a lot to recommend it. First, quality of product will be on public display, so the public will be able to make up its collective mind on a matter of public interest, namely safety of flight. Second, quality will likely improve.

Presumed-quality of SW has been for far too long judged by the process used to develop it, and not by objective properties of the resulting SW product. No correlation has been demonstrated in the scientific and engineering literature between the "usual" features of quality-of-process and the quality of the resulting product, except for those processes which explicitly involve determining objective properties of the product (such as the exclusion of possibilities of run-time failure). The goal of my standardisation work is to bring more focus upon evaluating properties of the SW product.

It seems to be both of those, at least. And who am I to judge its purpose?

PBL

No, I drive a real vehicle; a 2000 GMC stretched YUKON. It doesn't need any of that cr*p. I live in the U.S., so it's very doubtful I'd ever buy any foreign automobile. And don't look for me to visit anytime soon as I'm too busy here.

To be honest most modern cars have some element of "FBW" with electronic throttle (gas) pedals. I'd be dubious of buying a car with FBW type steering or braking systems though given how often systems like ABS or ESP seem to throw a wobbler.

Anyway, back to aircraft.

Surely being equipped with EGPWS negates about 80% of the debate in this thread?

"Yellow represents a cautionary alert 60-seconds prior to the predicted time of impact and is accompanied by a "caution terrain" aural message. And red indicates terrain that the aircraft could impact within 30 seconds; it is accompanied by an aural "terrain, terrain, pull up"

Given at worst case you have 30 seconds until terrain contact, the Airbus FBW protections will have no impact on clearance of terrain? Or is that too simplistic a view for some on here? :E

Atreyu :ok:

And therein lies the problem with a lot of the fine folks from the good 'ol US of A.

Never left the country, not willing to embrace other cultures, mind not open to other ideas, not willing to expand knowledge. Even if they have left the country they remain protected by the bubble that is their employer. I lived in the States for a year and the ignorance and insularism are quite astounding. No wonder you can elect presidents like Bush the Younger and possibly Sarah Palin! That's why I'm so nice to Yanks I meet outside the States, at least they've decided to take a look around.

Well I got some news for you, the rest of the world is playing and playing good. The only reason you buy a car from the 'States is patriotism, not for fuel efficiency, build quality, power, handling or looks!!! ESP is beginning to be incorporated in US cars, but guess what, it's made by Bosche, zee Germans!

There are certain contributors to this thread that if they were in charge of R&D for the human race would still have us waiting for lightning strikes to light our camp fires 'cos that's the way we've always done it' and are just about thinking that there's a better way of transporting stuff other than carrying it on our backs. Maybe you should go live with the Amish, I think you'd be happy there. :rolleyes:

Sorry if this sounds like an anti US rant, it's not, just get out and have a look how it's done elsewhere!

The problem with debating with such closed minds is that you can never win, even with evidence. They just won't see it.

Back in my box.

LD

True, though I'd always considered that incident a configuration failure (false WoW switch/ground mode), and as such, something not peculiar to the Airbus FBW models...

If you were referring to my remark [And don't look for me to visit anytime soon as I'm too busy here.], that was in reference to visiting that part of the World. I have been out of the U.S. MANY times. Most all of North America; a lot of South America; Japan, Korea, Australia, New Zealand, and parts of the South Pacific. Sorry if I didn't get to your part of the Planet.....yet. I won't bother to comment on the rest of your statements.

PBL
As far as I know, HAM did not imply any protection ... which one did you see ?
What is the FCOM reference that could correlate with the protection you think about ?

Better stop driving now then.

All my recent cars have had electronic throttles. They also have power steering, and without it I doubt I'd be able to turn the wheel unless I was already going quite fast (I don't fancy the idea of driving a 2.5 ton vehicle with failed power steering).

I'm sure older cars without power steering are rigged differently. Modern cars are heavy in comparison (I'm fairly sure it is more than just being used to power steering - I'm no lightweight).

Back on topic: FBW or no FBW - it took PILOTING SKILLS to put that A320 in the drink in almost one piece. FBW merely made moving the flight controls easier, protections or no protections. Would Direct Law have helped? I'm skeptical it would have made any difference at all.

Mech backup however... :E

Best regards,
ECAM Actions.

In the P-47 Thunderbolt Flight Manual is a chapter on Ditching. It is three sentences long.

Don't Stall.
Don't Ever Stall.
Don't Ever Ever Stall.

The nose will Pitch Pole, and disintegrate. No more Sully, no More Skiles, and probably most the rest. FBW not an issue, whatever. IMO. :ok:

at last we are getting somewhere. following on from bearfoils post lets just shorten the NTSB accident report quote from

to

um looks like a pattern starting to appear.

QUESTION: Did they ever get to the bottom of the Alpha Prot range? If not, the argument about protections against the stall are mute.

Too much emphasis is put on FBW protections, plain and simple. I suppose having g and roll protections were useful too? Let's not forget Alpha Floor protection. :E

Without any thrust from the engines, all Alpha Prot would allow you to do is have the highest rate of sink you can get at the lowest speed possible. Who is for about 3000 ft/min rate of descent at 125 kts?

The argument is ridiculous.

ECAM Actions.

maybe there is an argument for a different approach to FBW training at least.

It is shocking how many posters claiming to be pilots do not understand FE protections.

The only thing is that Sully would have had the proper tool to soften the touchdown and not having those mysterious additional features built into the system which attenuate pilot sidestick pitch inputs, preventing the airplane from reaching the maximum AOA.

Interesting enough that the NTSB was the first one to underline such characteristic when actually it should have been specified already 20 years ago by the BEA following the Habsheim crash.

Seems from the videos of his touchdown in the Hudson he did it perfectly. He could have done it equally well in any aircraft he was flying with his talent. Hopefully we all could do equally well. Automation is not designed to ditch an airplane but it seems in his case it didn't hurt the outcome of the event. Probably didn't help either. What worries me is when the new generation of pilots with computer skills take over. They won't have Sully's talent to just fly the airplane. What will they do if both engines quit? There is no button for that.

Before I say anymore I want to make it clear that I have the greatest respect for all of the crew involved in the Hudson river episode. It wasn't just flying skills that did industry proud on that day.

However one cannot ignore a few basic facts just because they don't fit conveniently in the nice little picture most of you have painted.

Well come on now you can't have it both ways. Perfect landing with control stick at full pitch up but with normal law limiting the input. NTSB stating that the outcome of the incident was improved because normal law was active.

That is quite clearly english for FBW played a positive role by assisting some superb flying under incredibly difficult circumstances.

The NTSB statement was completely unnecessary if the aircraft manual control inputs had remained within safe limits throughout the ditching. The reality is the system intervened to aid a perfect landing. In fact some have suggested that the FE protections allowed the crew to trade every available knot for a reduction in vertical speed.

That is not taking anything away from the pilot who undoubtedly was still the major factor in a successful outcome. The fact remains however, ego's aside, things may well have concluded differently. This seems to have been confirmed in NTSB tests carried out after the accident in the simulator where all 4 pilots crashed under similar circumstances.

So my point is you can't have one without the other. FBW is a fantastic tool and aids flight safety. It replaces ego with hard and fast software routines that will save your butt.

What it doesn't do is replace the pilot who still needs to be on top of his game.

Reply
 

really an awesome forum.
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Campervan Hire UK

Sully did not need alpha protection to make his Hudson landing. Only a pilot that would stall an aircraft before touchdown would need that. Don't most of us pilots approach a landing surface at 1.3 stall speed, flair to stop descent rate and roll it on with a perfect landing most of the time? We can do it power on or power off, on a runway or on the Hudson. Landing in the Hudson requires judgement on optimum flap setting and deck angle on touchdown with almost zero sink rate. You certainly don't want to be stalled or in a high pitch attitude when the tail hits the water first. Read Sully's book. He never said the Airbus automation helped him in any way and I am sure it didn't. Maybe it would help a mediocre pilot but not Sully. If alpha protection intervened on his Hudson landing the tail was probably already in the river so had no affect on the outcome. He would have never stalled into the Hudson. He was too professional.

That first sentence isn't really true. The control laws are significantly different between Normal and Direct laws, and I would imagine that while Direct Law probably gives Level 2 handling qualities, Normal law is undoubtedly Level 1, and may even be a "1" on the Cooper-Harper scale.. So even if the envelope protection features were never active, it is still highly likely that by taking the action to start the APU and thus maintain the aircraft in Normal Law, the crew gave themselves the best handling aircraft available to them and thus made the task of achieving the ditching easier (note: easier, not easy). I suspect its the improved handling in Normal Law the NTSB is alluding to here.

I don't think so. The NTSB statement is quite specific and has no place in the accident report unless it was related to the accident. It doesn't mention handling it mentions STALL

Safety Concerns contributed:





Best comment I have seen in years of reading Pprune (me SLF!).

I've seen this in a lot of tech related stuff, the philosophical aspects -why things have been designed in way X, and what can be expected of such a design as a result - are often left out of the training because of time pressure.

However, one can usually find some documentation which explains the design and what to expect from it.

Edmund

So, FE protections. CFIT. Honk back and roll max right. The Computer will escape nibbling at Stall and Rollover. That Right?? I like that one. But who would ever need it?

No one, but you try telling that to a certain section of this forum!!!

I refer you all again to this video, no one will ever need more than this, and the best bit is that you can't hurt the aircraft. As an aside though the memory items include rolling wings level to achieve max rate of climb unless you have a clear visual on the problem terrain. And also stow the speedbrakes (AA didn't a few years ago and lost a perfectly serviceable 757 to CFIT).

YouTube - Airbus A319 - Very Fast Crazy Take Off

LD