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Automation vs Seat-of-the-pants-flying talking as devil's advocate - so no abuse plea

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Automation vs Seat-of-the-pants-flying talking as devil's advocate - so no abuse plea

Old 31st Jul 2013, 19:18
  #61 (permalink)  
 
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Originally Posted by clandestino
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.
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.
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Old 31st Jul 2013, 20:47
  #62 (permalink)  
 
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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.
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Old 31st Jul 2013, 21:41
  #63 (permalink)  
 
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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..

Last edited by cucuotto; 31st Jul 2013 at 21:43.
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Old 31st Jul 2013, 23:46
  #64 (permalink)  
 
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Originally Posted by mross
I am asking, how do we, joe public, know how many times the FBW has prevented pilot error?
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.

Originally Posted by scotbill
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.
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.

Originally Posted by scotbill
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..
You have flown through windshear on big aeroplanes by feel? 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.

Originally Posted by scotbill
Bet it works just as well on your smarter-than-the-average-pilot Airbus.
It just doesn't work on anything when look through the windshield doesn't help in determining which way is up.

Originally Posted by RAT 5
I am also a paraglider pilot. I can & I do.
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!
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Old 1st Aug 2013, 00:58
  #65 (permalink)  
 
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Originally Posted by Clandestino
Originally Posted by Capn Bloggs
Immediately reacting when you feel the @rse falling out of the aircraft instead waiting for the sight picture to change always produces a better outcome.

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

Last edited by Capn Bloggs; 1st Aug 2013 at 01:16.
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Old 1st Aug 2013, 02:27
  #66 (permalink)  
 
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Originally Posted by mross View Post
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.
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.
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Old 1st Aug 2013, 03:02
  #67 (permalink)  
 
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"FBW and automation are two separate concepts."
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.
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Old 1st Aug 2013, 03:52
  #68 (permalink)  
 
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Originally Posted by CONF iture View Post
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 ...
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.
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Old 2nd Aug 2013, 14:50
  #69 (permalink)  
 
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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".
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Old 2nd Aug 2013, 15:07
  #70 (permalink)  
 
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@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.

Last edited by DozyWannabe; 2nd Aug 2013 at 15:11.
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Old 2nd Aug 2013, 18:34
  #71 (permalink)  
 
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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.
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Old 2nd Aug 2013, 19:35
  #72 (permalink)  
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FBW and automation are two separate concepts.

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!!!
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Old 2nd Aug 2013, 20:37
  #73 (permalink)  
 
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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.
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Old 2nd Aug 2013, 20:57
  #74 (permalink)  
 
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Originally Posted by FCeng84 View Post
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.
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.
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Old 2nd Aug 2013, 20:59
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Originally Posted by dozy
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.
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.
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Old 2nd Aug 2013, 21:09
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Originally Posted by CONF iture View Post
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.

Last edited by DozyWannabe; 2nd Aug 2013 at 21:22.
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Old 2nd Aug 2013, 21:37
  #77 (permalink)  
 
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Originally Posted by dozy
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.
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 ... ?
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Old 2nd Aug 2013, 22:28
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Upon further checking, it's all down in the report.

Originally Posted by D-AXLA BEA report (p.186)
Position of the elevator in the last seconds

From 15 h 46 min 00 s and until the end of the flight, the position of the
Captainís sidestick was at the pitch-up stop with a median transitional position
of one second at 15 h 46 min 02 s. At the same time, the elevator position
remained in a nose-down position.

Two factors can explain this phenomenon while the law in the longitudinal
axis is a load factor law (the sidestick at the stop commands a normal load
factor of 2 g):
- A rapid increase in the pitch is offset by the flight control law,
- A load factor higher than the value commanded leads to a nose-down
movement of the elevator.
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.
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Old 3rd Aug 2013, 10:52
  #79 (permalink)  
 
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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.

Last edited by Centaurus; 3rd Aug 2013 at 11:37.
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Old 3rd Aug 2013, 13:30
  #80 (permalink)  
 
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As I understood flying all these years manual flying you make things happen, auto flight watch the things you want happen. Nobody puts AP on and goes to sleep. How can you not monitor speed? Auotomation does not mean you don't scan. SFO type incidents cannot happen in isolation. These are examples of pilots slowly loosing their scan over the years. Other than manual control inputs everything else remains same. Unless offcourse there was extreme fatigue and sleepiness then anything is possible.
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