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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 15th Sep 2013, 01:17
  #181 (permalink)  
 
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Originally Posted by 737er
The autopilot had to be disconnected on Apollo 11 to prevent a crash.
To be fair, that was triggered because Buzz Aldrin (reasonably, though contrary to procedure) left the rendezvous radar on standby during the descent in the event of an emergency abort. What he didn't know was that leaving it on would steal cycles from the guidance computer in the early stages of descent. This resulted in the LEM ending up somewhat downrange of its original intended landing point.

That point aside, I completely agree.
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Old 15th Sep 2013, 02:02
  #182 (permalink)  
 
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one gust and you can be spiraling in short order...all planes want to spiral but it's is indeed. ususually a slow process if in trim in smooth air...the point is one has to handfly routinely in oorder to be better equipped to deal with more exotic flight conditions...
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Old 15th Sep 2013, 02:10
  #183 (permalink)  
 
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I'm not arguing that second point PA, I agree!

However - looking at the DFDR traces shows the yaw damper working overtime to successfully keep the aircraft upright during even the most extreme gyrations.

I'm not saying leave the controls alone entirely, just that the first point of order should be to see if the aircraft will remain relatively stable without encouragement - which in most cases it should!
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Old 15th Sep 2013, 02:27
  #184 (permalink)  
 
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but you get your hands in the flight controls and eyes on the instruments immediately...but in most cases there are no fast hands in a jet...on that point you are corrrect
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Old 15th Sep 2013, 02:32
  #185 (permalink)  
 
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Yes - as I said about controls - "cover them (meaning get your limbs in a ready position) and be prepared to use them". If you start making inputs without assessing the situation then you're more than likely to get it wrong and end up fighting yourself - as happened with AF447.
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Old 15th Sep 2013, 02:39
  #186 (permalink)  
 
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It`s (To borrow a USAF term) HOTAS Hands on stick and throttle no inputs necessary but hands on ...
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Old 15th Sep 2013, 05:10
  #187 (permalink)  
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@ 737er - Apollo

The Apollo missions were 40 years ago! The damage was most serious for the life support systems which would not have been fitted if the pilots were not installed! Other systems were there to get the humans home, again not required on an autonomous mission.
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Old 15th Sep 2013, 12:01
  #188 (permalink)  
 
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I'm not saying leave the controls alone entirely, just that the first point of order should be to see if the aircraft will remain relatively stable without encouragement - which in most cases it should!
If I recall, a Lion Air Indonesia B737 went into a gradual spiral at night with devastating consequences. Seems the crew were having difficulties with one of the to IRS. in fact there were many reported snags on that IRS previously.

Again, from memory, the crew decided to trouble shoot and switched off one of the IRS and in turn this caused the automatic pilot to disconnect. Either the crew didn't realise the autopilot had disengaged or if they did, neither pilot was allotted the task of flying the aircraft manually.

While one pilot read from the QRH about IRS non-normal, the other pilot selected the perceived offending IRS to the Attitude mode. This blanked out the PFD on one side. Meanwhile the 737 wandered around the sky at night with no one watching the flight instruments. It eventually went into a gentle spiral which got worse. By the time someone exclaimed WTF, the aircraft was in an unusual attitude.

The captain didn't have a clue how to recover from a UA and instead pulled back hard on the control column while in the spiral. It doesn't take too much imagination to guess why the aircraft eventually broke up in mid-air.

the point is one has to handfly routinely in order to be better equipped to deal with more exotic flight conditions...
And therefore the Lion Air crew went in...

Last edited by Centaurus; 15th Sep 2013 at 12:04.
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Old 15th Sep 2013, 22:14
  #189 (permalink)  
 
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interesting about lion air

the solution is obvious

the autopilot controls the plane at all times unless you continuously push a button on the yoke, then you fly it , fly it like the old days with no limiters.

and if the button shorts out, it turns the autopilot off and announces it as loud as a san francisco fog horn.

sound familiar? mooneys used this idea for their wing leveler
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Old 16th Sep 2013, 10:45
  #190 (permalink)  
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Quote:
Are you saying that automation contributed to the Asiana 214 crash??? It sure looks like an automated landing would have prevented the crash.

Quite the reverse: the automatics may have been masking a threat in the system. For that particular approach the outcome may have been better if a higher level of automation had been used but that does not address the fact that there was a crew (and still undoubtedly are still crews) out there who given the wrong set of circumstances could not (and cannot) safely guide a serviceable aircraft to a runway in benign meteorological conditions.

The reality is that airlines are best served by having well rounded individuals in the flight deck and a key part of the necessary skill set is piloting skill. Piloting skill is not acquired and maintained by watching screens with one's hands sitting idly on one's knees.
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Old 16th Sep 2013, 13:00
  #191 (permalink)  
 
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speedrestriction:

Very succinct, very logical analysis of the root cause.
Matter of fact, the problem is greatly similar to automation in broadcast radio. When unattended, the system chirps merrily away sequencing music, ads, PSAs and other announcements untouched by human hands.

But when I (as a volunteer engineer/producer) take over manually, the computer is put on HOLD, and manual ops are just the same (almost) as during my student days 50 years ago. And executing a fast-paced audio sequence is not so emotionally different from landing in a crosswind. In a taildragger.

Last edited by barit1; 16th Sep 2013 at 13:12.
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Old 16th Sep 2013, 13:23
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Pugilistic Animus
Airbus FBW does not get into spiral even with one engine fail and TOGA on live engine because the computers try to hold the position. Any tendency to spiral is prevented by computers by applying rudder upto yaw damper's authority and bank is prevented by applying opposite aileron and spoilers. Since yaw dampers cannot apply the required amount of rudder the aircraft does a skidding turn with MAX 5 to 7 degrees of bank. Even in Unreliable speed the aircraft is in alternate law so behaves the same way except it can be stalled or get into overspeed. You must disconnect AP, ATHR and switch off FDs and the a/c will maintain its pitch and bank.
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Old 16th Sep 2013, 13:57
  #193 (permalink)  
 
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vilas thankyou for the airbus AP information..very interesting....my knowledge of Airbus systems is nonexistant
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Old 17th Sep 2013, 12:40
  #194 (permalink)  
 
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OK465
I was talking about A320 behaviour OEI in normal law and AEO in unreliable speed in alternate law.
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Old 17th Sep 2013, 14:19
  #195 (permalink)  
 
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Hands off, in ALT2, roll Direct, A330 with one engine TOGA and one engine failed, the aircraft will spiral (somewhere in the 70-80 degree bank range). It will not however roll over on its back.

What happened to the A330?? from Toulouse on take off being flown by test-pilots that crashed. Was it not something like this? I never did see the final report.
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Old 17th Sep 2013, 16:26
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Originally Posted by RAT 5
What happened to the A330?? from Toulouse on take off being flown by test-pilots that crashed. Was it not something like this? I never did see the final report.
No - that one *was* automation and interface related if I recall correctly. The mode set in the FCU panel was Altitude acquire, which disabled the *autopilot* pitch protection - the FBW alpha protection was unable to correct in time given the incorrect pitch trim, extreme aft CG and power plus very low altitude. They changed the interface soon afterwards.

Airbus Industrie Flight 129 - Wikipedia, the free encyclopedia

Last edited by DozyWannabe; 17th Sep 2013 at 16:43.
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Old 17th Sep 2013, 17:26
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Well yes, no argument there - but the original query was talking about AF447, which had no such asymmetric thrust condition.

I'm not sure at what point thrust asymmetry entered the discussion, and in any case you'd want to determine the direction of the thrust asymmetry before making corrective inputs no matter what kind of aircraft you were flying, would you not?
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Old 18th Sep 2013, 00:16
  #198 (permalink)  
 
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Originally Posted by Centaurus
If I recall, a Lion Air Indonesia B737 went into a gradual spiral at night with devastating consequences. Seems the crew were having difficulties with one of the to IRS. in fact there were many reported snags on that IRS previously.
Hi Centaurus,

I can't find a Lion Air incident matching that profile - are you sure you're not thinking of Adam Air 574?

Admittedly it wasn't at night, but the weather was pretty rotten. The Captain was experienced, but new to the airline. They had INS issues as you say, exacerbated by the fact that the aircraft tended to roll to the right when AP was disengaged. They attempted to reset the two INS units without realising that this should be done on the ground, or at the very least with wings held level (as a last resort only). The INS therefore reset itself with a significant tendency to roll right and the rest is history.

The issue was in part incorrect problem-solving on the part of the crew, but underlying that was a significant can of worms regarding company maintenance. One of the leading theories was that the airframe itself was damaged, leading to a tendency to roll to the right, but as soon as AP was engaged, the automation compensated. The Captain noticed this when AP disconnected, hence his desire to re-engage in order to troubleshoot. He incorrectly assumed that the right roll tendency was a fault within the automation, and I have to wonder how many other pilots would have done the same?
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Old 18th Sep 2013, 13:09
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I can't find a Lion Air incident matching that profile - are you sure you're not thinking of Adam Air 574?
Apologies. You are quite right. I meant Adam Air.
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Old 18th Sep 2013, 13:19
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You could argue that allowing the ins to be reset when the a/c was not on the
ground was a system design failure. Even if you could reset with wings level
in flight, all you have then is an attitude and perhaps vector reference and
not an ins.

Some of this kit is just bad by design, but that issue was discussed at length
in the AF447 thread with no concensus, fwir :-)...
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