Agreed. That "sense" comes with practice. ;)

from the OP
 

By seat-of-the-pants-flying I meant flying using the feel of the controls to tell you what the aircraft is doing - the force feedback from the stick and pedals and the noise of the engine and airflow and the little clues that the early pilots used; the guys and gals who flew with no instruments. I have only flown little Cessnas but I do have a license! I've done a few cross-wind landings and a spin recovery so I think I know a little about the basics. Of course, as I admit, I know nothing compared to the professionals on here but quite a lot compared to some wannabe's.

"the intent of the OP is pretty obvious ;)" not sure what you mean Capn Bloggs
- I only intended to debate aviation, I did not intend to rile anybody and apologise if I have offended anyone. I did say, 'as devil's advocate' meaning that I take a position with the purpose of debating.

Right, but one thing to be clear on is that light aircraft like your Cessna will have direct cable control to the flight surfaces. Jet airliners are a little different in that older short-haul types like the B737 and DC9/MD-80 will have hydraulic assist with cable backup and larger widebodies such as the B747, DC-10 and A300 as well as newer narrowbodies like the B757 are all-hydraulic. Nevertheless all of them have an "artificial feel" system which approximates and translates the forces on the flight surfaces to the flight controls.

Boeing's FBW system uses computerised force-feedback algorithms to provide artificial feel on the B777 and B787, and Airbus's FBW system uses passive spring feedback which is not linked to the surfaces in any way.

Therefore in a technical sense, control feedback on airliners is usually at one remove from what the flight surfaces are actually doing. Which is why a holistic approach using all the information available to a pilot, with an integrated scan paramount, is likely to get the best results.

I may be a wannabe, but I'm savvy enough to know that your pants (or more precisely your inner ear and nervous system) are more likely to lie to you about your situation than your instruments are.

Hi DozyWannabe,
Only true for Airbus FBW.

On Airbus you select a rate (as you remind me from time to time).
On Boeing you select a flight surface displacement.

Hi rrr,

I meant in a physical or mechanical sense - which applies to all the types I listed. Whether electro-mechanical or digital, artificial feel is just that - artificial.

[EDIT : Which is to say that on most jetliners with "conventional" controls, flight surface feedback is mitigated by the artificial feel system and therefore at one remove. Airbus's FBW system, as I said, uses passive spring feel and dispenses with flight surface feedback entirely. ]

Ref: seat of the pants. I take this to mean being sensitive to the g sensation of flying. I'm still amazed by pilots who can't sense this. You're looking out of the window on finals and you hit a thermal and feel the a/c ballooning. By instinct you correct the attitude to stop the balloon and adjust thrust to maintain speed, just a tad. Now one thing is pretty certain is that if you fly into a thermal, and it's not too close to TDZ, i.e. you are at some height on finals, then you are going to fly out of it and the a/c will sink there after. Not only are you fore-warned, but you should feel the world falling out of your a/c and 'adjust' attitude and thrust just a tad to resist mother nature.
It doesn't happen that good. If the automatics are in it is masked, if they are disconnected their bum is not connected to the a/c not their brain. They follow the speed loss/gain rather than pre-empt it.
Solution: Change the selection criteria for todays pilots, perhaps? Are the correct senses and skills being assessed?

The Irony
 

How ironic is it that Hollywood generally would have you believe that no matter how advanced technology gets, nothing beats the seat of the pants ability of a crusty old dinosaur or hot shot ala Star Wars/Space Cowboys/Flight etc

So why automate to such a degree? Its an industry driven by accountants and engineers.

As an aside, the need for a human operator within the cockpit will probably exist until all processes of air travel becomes fully automated.

To DozyWannabe
 

"Envelope protection and the like is a different matter entirely, and only enters into the equation extremely rarely."

How can you sure of this? Meaning how do you (DozyWannabe) know when the protection has limited the effect of the pilots input?

I agree with all you said in post 43. And thank you for not rising to my little jibe :)

It's pretty :mad: obvious: if you're pulling like :mad: and the thing doesn't stall, you try to bank to 60° and the thing won't do it, you end up in the 30° dive with the speed rocketing towards the barber pole the power comes off and the nose comes up by itself...

to Capn Bloggs
 

Sir, I'm sure YOU know! I was asking how DozyWannabe claims to know that the automation/envelope protection rarely cuts in.

There are reasons for this though. Modern UAVs by and large are single engine and are not certified with the levels of redundancy exhibited by transport category aircraft. UAVs don't bother with systems such as anti-icing and de-icing and by and large still have a human operator to land them (Predator is landed on site and is not autoland) and its for these reasons the loss rate is higher.

Do I see completely autonomous transport cat aircraft in the mid-term? No. I can imagine a single pilot operator though, sat in first, on some pretty hideous crew duty days who can step in if there is multiple system failure. We wont see the step straight over to no pilots, but there will be an intermediate step whilst the concept is proven and issues shaken out imho.

Wouldn't surprise to see freight flown as UAVS in the future. Whatever the case, any pilot who pretends that the boxes won't break, hoping he will never have to hand fly or mentally navigate is beyond contempt in my book and is part of that special crowd of pilot who 'networks' for a seat in a plane, in the hopes that sitting in a plane, with a title of 'pilot' suffices to all his friends that he actually is one.

FedEx-founder Fred Smith posted this in 2009:

and

What he says mostly makes sense to me (my biggest doubt at this point is that he claims it will be "safer", that remains to be proven, but no human pilots on board may well be safer in terms of loss of human lives, if the things can manage to avoid crashing into humans on the ground and in other airplanes). It's also interesting to note that the unmanned X-47B which just completed first carrier landings is a blended wing design.

In response to VinRouge: following Smith's line of thinking, I'm not sure if we will see single pilot operated transport category cargo aircraft first. It's not a necessary intermediate step to what he wants. A more likely evolution, as I see it, would be to let Boeing gather experience with the Phantom Ray, maybe they'll even win the contract for the US Navy UCLASS and then, much later, when the military technology matures, start to work with them to look at the feasibility of larger civil cargo UAVs.

You also mentioned that This may be true right now, but it will change. Carrier-based UAVs use task based automation, including autoland, mainly because there is no current datalink technology which is fast and powerful enough to allow something as precise as a carrier landing to be remote controlled, and autoland on the other hand is known technology.

But for civil aviation this is not even at the stage of long term strategic planning, but merely a visionary concept. Four years later, we're not really much closer to Fred Smith's aspirational idea. It will no doubt happen, that's not the question. The question is when? There I agree with previous posters, it will take at least two decades, most likely longer, with a caveat that it's hard to predict anything, particularly the future.

Just applying military experience to design civil UAVs won't be enough, there's many civil aviation specific issues that will need to be addressed. Military UAVs mostly operate in a very different kind of airspace (think of separation and control). Civilian (partly) autonomous/automated UAV would need much better sense-and-avoid technology, eg the ability to interpret video images, radar, as well as transponder/ADS-B data, to maintain separation. Also, the military owns and operates satellites and has huge network bandwidth at it's fingertips which can relay images to the ground with short latency. Civilian/Commercial UAV operators would have to buy bandwidth, and even compete for the spectrum with other uses if they want to t/x huge amounts of data to allow for remote control. And finally you also need FAA to certify all this new technology which could easily add 20 years alone...

Don't take it from me - let Bruce Dickinson show you:

Now, this being recorded for a mainstream tv programme, Bruce does leave out a few key points - chief among which is that the Normal Law hard protections are not just there to guard against mistakes, but also allow the pilot to execute evasive manoeuvres at the full extent of the control movement without overstressing the airframe.

The reason I said the hard protections rarely come into play is also illustrated in the video. Bruce (at the time an Astraeus B757 Captain - in fact he was F/O on a flight out to Barcelona that I took with the missus) demonstrates that in normal circumstances he would not execute a bank manoeuvre much past 25 degrees. Bank protection only kicks in at 67 degrees, so if we take his own limit as a reasonable one for a line pilot then you're not going to see that part of the protection come into play very often.

Alpha Prot and Alpha Floor are likewise only designed to come into play when at risk of stalling, and again - on a day-to-day basis we're talking about very rare occurrences, are we not?

to DozyWannabe
 

You have misunderstood my question. I know what the envelope protection does. I was asking, if a pilot somewhere in the world asks the aircraft to go outside the envelope and the protection becomes active, how would you or I ever know? We likely would not read about it. I suppose the airline would know - from the flight data recorders.

mross,

There's something called FDM in the aviation industry: Flight Data Monitoring!

Pilots in most companies will get invited to "Tea and biscuits" with the "Chief pilot" when he/she significantly exceeds normal flight parameters, without even getting close to flight envelope protection!

When a pilot messes up so badly that flight envelope protection has to kick in, it will be known! And yes, this will happen only very rarely!

Of course, not all of these very rare occurrences will make it to the press, and you and I might not hear of it. The simple fact that reaching the flight envelope protection is very unlikely, is, by logic, enough to say that these events occur only very rarely. Back to topic now, please.

to Sabenaboy
 

Yes, we know, it's called many other things too.....

Flight Data Monitoring (FDM), Operational Flight Data Monitoring (OFDM), Flight Operations Management (FOM), Daily Flight Operations Monitoring (DFOM), Flight Operations Quality Assurance (FOQA), Flight Operations Data Assurance (FODA), Maintenance Operations Quality Assurance (MOQA).

In Perpignan, looking at the elevator trace, the final resource has been limited by something, most probably the vertical acceleration ... But the BEA has never published that data ...

Actually, ATHR performed as designed, retarding the throttles on ground. How did it "know" it was on ground? In computer logic; if RA is zero, then one has to be. It was not outright failure of radalt, it kept emitting realistic value, which had no semblance to actual, it's what we call "unreliable".

You can not teach today's computers to deal with unreliables. It takes intelligence to tackle them and success is not guaranteed.

Except in rare cases where those feeling their nether regions falling out are actually victims of somatogravic illusion.

I'm still amused by PPRuNers seriously suggesting that personal g feel is something that can be used to fly transport aeroplane successfully.


Discrepancy between Hollywood movies and real world is part of the answer.

You have answered your own question, lest you just know the names for it and are unaware what it means.

He had read and understood them manuals.

:confused: What was the point of previous question, then?

Parbleu! Scandaleuse! We should self-righteously and indignantly reject the report on shoddily maintained and lousily test flown 320 because there is no G trace in published FDR readouts. :E

to Clandestino
 

Did you read post 1?

What I am interested in is how many times FBW automation intervenes and stops the pilot from making errors, and comparing this to the more well known cases where the pilot has had to prevent the automation doing something to hazard the aircraft. I'm not asking how does a skilled ATPL knows when the automation is limiting his input's affect on the a/c. I am asking, how do we, joe public, know how many times the FBW has prevented pilot error?

Don't know what your experience is but anyone who spent any significant time operating in extreme windy environments such as the Highlands and Islands of Scotland probably has a very refined personal g feel.

It pays off particularly in windshear situations where there have been dramatic power changes and has saved my personal bacon on big aeroplanes on several occasions..

Bet it works just as well on your smarter-than-the-average-pilot Airbus.

No, those are accepted facts, but we see a partial report where all the story is not told. Anything that could tarnish the Airbus concept has to be ignored. The BEA will comply.

Quote:
Originally Posted by RAT 5
Ref: seat of the pants. I take this to mean being sensitive to the g sensation of flying. I'm still amazed by pilots who can't sense this.
I'm still amused by PPRuNers seriously suggesting that personal g feel is something that can be used to fly transport aeroplane successfully.

I am also a paraglider pilot. I can & I do. It has saved me on a few occasions where the world was about to fall out of the aeroplane just at the start of the flare, and when on finals in a very hot Spain a combination of orographic updraft amplified by thermals, or each on there own, was trying to fling me skywards above the glide path. Even more interesting on a pure visual. It teaches you to be proactive and lead/control the machine rather than be reactive and be led by it. From the ground I've watch very large a/c being tossed around on a very active thermal day. Quite educational and spectacular.

Flying an airplane, automation or not automation, in the safest way possible requires exceptional skills. Flying an airplane from A to B with a statistically acceptable risk requires almost zero skills. Unfortunately there are not enough exceptionally skilled pilots around.People that should stay well clear from a cockpit, thanks to various converging and inexplicable contingencies , find themselves inside of it with no real merit or quality if not an apparently sufficient proficiency. Unfortunately lack of basic coordination, of psycho motive intelligence, can only be partly offset by luck and automation and when either of the two turns its back... A new generation of pilots with no skill has been produced by cadet programs whose selections process were based not strictly on pertinent aviation qualities but more on psychological profiling, potential employee loyalty , docility and ease of domestication , plus often a series of non aviation related educational parameters and last but not least ..connections.
Another even worst part of this generation of pilots just bought there way into the cockpit of an airliner without even paying their due in the incredible school that is general aviation. Automation cannot cope at times..

Certain Joe Public can't know that. Not because it is some top secret but because our poor Joe was totally unable to understand what DozyWannabe and Sabenaboy wrote. Talking about hiding the answer in plain sight.

How many times? Not many. Then why do we have it? Because unprotected types are still performing unintentional aerobatic maneuvers interrupted by ground every couple of years.

How many full IFR twin (or more) turbined transport category aeroplanes are operating the Highlands and Islands of Scotland? Is there a photo of Triple seven roaring down the Mach Loop?

G feel is very fine for folks flying with constant outside reference. Not so for IFR pilots in IMC.

You have flown through windshear on big aeroplanes by feel? :eek: My, if it is so good technique, it should be put in training manuals instead of "watch your attitude, watch your speed and beware of illusions" which is current party line.

It just doesn't work on anything when look through the windshield doesn't help in determining which way is up.

Do what? Fly your paraglider on instruments? Everything you describe afterwards happens if not in legal VMC, then at least with significant outside visual reference!

Another typical Prune rant by Clandestino. Must have just got back from a long trip.

I was obviously talking about flying down final and landing! Did you read the bit about "sight picture" ie looking out the window? When has there ever been an SI event then? :cool:

And what I've been trying to tell you is that FBW and automation are two separate concepts.

Now, in these modern days of QARs and FOQA etc., you can be sure that if any of the protections were triggered they would be logged, and the airline would have to deal with it.

Thank you for trying to make this clear, including your other post: http://www.pprune.org/tech-log/51974...ml#post7960740

This is very commonly misunderstood. In the book "The Rio/Paris Crash: Air France 447" by Roger Rapoport, he frequently confuses the two concepts -- and that in a book dedicated to analyzing that crash!

It is exactly as you said: envelope protection and automation (whether autopilot or FMS) are two different things.

You can have automation without envelope protection, as was typical for years. Likewise you can have envelope protection without automation -- you could manually hand-fly an Airbus and never engage any autoflight system.

In some cases there is a loose connection between the two. On Airbus, autothrust may automatically engage to protect alpha floor. Likewise in cases like AF 447 an anomalous event can simultaneously disengage both autopilot and envelope protection. However they are two different things, coincidentally connected by the same event.

Admittedly the aerospace community does not universally adhere to this distinction in terminology. NASA refers to the space shuttle's fly-by-wire system as a "digital autopilot", even when being hand flown.

Unless the data was relevant to the accident sequence (which in this case it probably was not) then there was no need to delve into that behaviour, and thus there was no need to publish. The BEA exist to investigate accidents, not to reverse-engineer every aspect of the aircraft.

If an accident report does not at least touch upon all likely causes, even if some are unresolved, then I regard said report as "lightweight". :uhoh:

@barit1 - I'm going from memory here, but I think the trace to which CONF iture is referring occurs well after the accident sequence is established. I'd have to dig up the report again to be sure, but given the usual way BEA reports are written I'd expect there to be some reference to the trace, and why it was excluded.

As an aside, I note that a lot of commenters on the Dubai UPS 747F report are holding it up as exemplary, and indeed it is very thorough. However I also note that the only traces in the report itself consist of a single combined graph on the final page. Now that's perfectly reasonable as it contains all the relevant data - but it does cause me to question the apparent double standard at work, when some are censuring the AF447 report, which had more complete traces over several pages and a whole appendix, as being somehow incomplete.

At simple airfields without RNP1or PRNAV procedures, fly manually without the automatics for all you want...certainly strongly encouraged. However trying to fly PRNAV SIDs and STARs without the automatics may get you invited for tea & bikkies with the CP as the FDM/FOQA snoop dogs are forever on the prowl should you come close to exceeding the tolerances inherent in those precision procedures.

FBW and automation are two separate concepts.
 

This is nonsense. FBW relies heavily on automation. You cannot separate them.

In level flight with zero sidestick input the flight surfaces are still moving to maintain 1g - This is automation!!!

A few definitions: FBW - Augmentation - Protection - Automation
 

I applaud the recent entries in this thread making the case that FBW and Automation are two different concepts. I would like to add a third term: augmentation. Here are the definitions of these three plus protection that I use. I have found these to be very helpful in explaining the evolution of and difference between airplane control systems.

Fly-By-Wire (FBW): This refers to the connection between pilot input and control surface motion as being other than a mechanical link. An airplane configured with electric sensors on the pilot's controls (sensing either force or position) and control surface positions commanded proportional to those pilot control positions has a FBW control system. The surfaces go where the pilot commands them such that the pilot to control surface linkage behaves the same as if mechanical linkages between the two were used. Most FBW control system are more complex than this, but strictly speaking this simple example qualifies as FBW.

Augmentation: This refers to the motion of the control surfaces being more than just a reflection of the pilot's controller positions. Yaw dampers are an example of early augmentation wherein the rudder command is the sum of the pilot command via the rudder pedals and the control system yaw damper command. Note that for this example, augmentation was introduced without FBW. More recent examples of airplanes with high degrees of augmentation are the A320 and later Airbus designs and the B777 and later Boeing designs. For these airplanes maneuver demand control is provided in one or more axis such that the pilot's controller position commands a maneuver (e.g., pitch rate, roll rate, sideslip angle) rather than a direct surface position or an addative increment in surface position. Augmentation allows for closed-loop (i.e., control system active) handling qualities to be different from those of the bare airplane. This allows for the airplane configuration to be optimized in the direction of improved performance at the expense of open-loop (or unaugmented) handling qualities. The control system augmentation enables configuration features that improve performance.

Protection: This refers to features of the control system that reduce the likelihood of operating near or beyond edges of the flight envelope that present degradation in airplane performance and/or controllability. Protection functions come in many forms. Some such as stick shakers and nudgers provide pilot awareness. Others such as angle-of-attack or bank angle limiters provide hard limits that the pilots are not able to command beyond. Similar to early examples of augmentation, early protection functions were introduced without FBW. The more elaborate protection functions found in recent airplane models require FBW in order to allow for control surface motions that differ significantly from the pilot control positions as observed on the flight deck.

Automation: This refers to the basic concepts of autopilot and autothrottle. With automation engaged, the pilot can go hand's off for extended periods of time. Autopilots and autothrottles were introduced to commercial airplanes long before FBW. For these systems the autopilot effectively moved the pilot's flight deck controls to provide commands to the surfaces and the engines in the manner that the pilot would when flying manually. With the introduction of FBW where there is no mechanical linkage between pilot controls and the surfaces or the engines it is possible to implement automation without motion of the pilot's controls. Airbus has chosen this simpler route such that the pilots controls are not driven to show autopilot and autothrottle commands when those automation functions are engaged. Boeing has chosen to actively back-drive the pilot controls when automation is engaged as a means of providing situational awareness to the flight deck crew as to what inputs the autopilot and autothrottle are making to the airplane.


I hope that these definitions help provide clarity to further discussions within this and other PPRUNE threads.

Absolutely correct. In fact it goes back even earlier to pure electro-mechanical devices such as the aileron/elevator boost in the '50s-era propliners. Congrats on a succinct, concise and informative post, that I may well squirrel away for later use myself!

mross - I hate to say it, but you're well off-base here.

As the elevators did not follow the pilot request, there must be a reason. That's the job of the BEA to detail that reason.

No, it's the job of the BEA to ascertain the factors relevant to the accident sequence, and the report they produce will focus primarily on those. In this case, a discrepancy in surface deflection versus command at a point in the sequence when the flight control system is already compromised - and as such would have no bearing on the outcome - is likely to be a waste of effort. Therefore they note the discrepancy and leave it at that.

Look at the UPS 747F report. The investigators can say that whatever the fire and heat were doing to the control junctions was affecting the control surface response in terms of control input versus surface deflection, but they don't have sufficient data to say precisely what the damage was. Because in that case it was directly relevant to the loss-of-control sequence they consider scenarios, but all those scenarios are speculation.

Negative - you don't keep silent on such important flight control characteristic, unless you want to stick to a partial story.
Pulling one more G was maybe all it took to come back home ... ?

Upon further checking, it's all down in the report.

Further reading of the report indicates that the aircraft was in Abnormal Attitude Law (in which longitudinal/pitch is determined by load factor) at this point, not Direct.

Also, judging by the flightpath an extra 1G would have done them no good at all.

22 July 2013 Aviation Week and Space Technology has published an editorial called "Ending Automation Addiction"

One excerpt states; The automation dependency paradigm must be changed now. Crews must be trained to remain mentally engaged and, at low altitudes, anytime they wonder "what's it doing now?" the response should be to turn automation off and fly by hand.

Well, we saw the disaster of Asiana 777 on a visual approach where the pilots switched to hand flying and promptly crashed.

Boeing, on the other hand in its flight crew training manuals state: .."reducing the level of automation as far as manual flight may be necessary to ensure proper control of the airplane is maintained. The pilot should attempt to restore higher levels of automation only after aircraft control is assured".

It seems to me that Boeing are only playing lip service to the need for keeping up manual flying skills since in that last paragraph they quickly encourage the pilot to re-engage the automatics.

The only way to teach today's pilots not to be frightened of hand flying is to ensure that type rating training in simulators starts off by teaching pilots how to fly manually without flight directors and auto-throttles for the first few sessions before automatics are introduced. After that, recurrent training in the simulator should include a high proportion of manual raw data flying.

There is little hope that airlines will ever seriously permit their pilots to hand fly meaningfully on revenue flights; especially in IMC. By that I mean FD off using normal manual flying techniques. Hand flying focusing exclusively on keeping the flight director needles centred does little to improve manual or instrument flying skills.

That being so, simulators must be used increasingly for the purpose of keeping proficient in the task. The accident record of crashes caused in the end, by automation dependency, has demonstrated the folly of closing eyes to the problem described in the Aviation Week editorial and in numerous well researched studies on the subject of automation addiction.