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Turkish Airlines cargo 747 crashes in Kyrgyzstan

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Turkish Airlines cargo 747 crashes in Kyrgyzstan

Old 27th Mar 2017, 14:51
  #341 (permalink)  

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Airmanship. RIP
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Old 31st Mar 2017, 08:23
  #342 (permalink)  
 
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https://www.flightglobal.com/news/ar...inquir-435569/
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Old 31st Mar 2017, 09:17
  #343 (permalink)  
 
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Notwithstanding the complete lack of awareness during the arrival/approach, had they flown the GA correctly they'd probably have got away with it. According to the report:

01:17:05 - Pass DH
01:17:07 - FO states 'minimums'
01:17:08 - Capt states 'negative' (not visual)
01:17:09.5 TOGA pressed

So, the GA was initiated 4.5 seconds too late. Had they initiated the GA correctly ('at or before DH') we'd be none the wiser about their astonishingly inept approach!
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Old 31st Mar 2017, 09:17
  #344 (permalink)  
 
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Must have been scary for the FO to see the runway passing by on the NAV display but still descending....
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Old 3rd Apr 2017, 03:07
  #345 (permalink)  
 
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Hi guys,

I'm having a bit of trouble understanding what's going on in that report. Looking at figure 1, it looks like the aircraft captured the 9 degree glideslope, with a VS of 1400fpm.

My understanding is that when the GS is lost, the AP will continue in an "inertial mode" descent, with the associated failure flags. What I don't get is why the aircraft seemed to descend on a 3 degree slope, parallel to the GS, instead of the 9 degree slope that it had captured. Why wouldn't it continue at 9 degrees?
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Old 3rd Apr 2017, 07:30
  #346 (permalink)  
 
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Why wouldn't it continue at 9 degrees?
Because the "inertial mode" is intended to jump in temporarily during a 3° approach with a poor ILS signal lost temporarily. There is no 9° approach for a 747, which would be far beyond the "steep approach" some significantly smaller aircraft are certified for.

The real question is: How can you cross two markers (Outer and middle) without doing an altitude check? The according numbers are on the approach chart, so no math included. Dead simple crosscheck, but not done.

If you do no crosschecks, you are not allowed to do any mistake or darwin gets you.
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Old 3rd Apr 2017, 07:36
  #347 (permalink)  
 
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My take is that the system error checking is more than just loss of the glideslope signal but also 'reasonableness' of the signal. Obviously a 9° slope is not reasonable, hence error flags and reversion to an inertial 3° descent waiting for a reasonable signal to return. In this case it never did because the aircraft was never near the correct 3° path.
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Old 3rd Apr 2017, 07:46
  #348 (permalink)  
 
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Originally Posted by Volume
The real question is: How can you cross two markers (Outer and middle) without doing an altitude check? The according numbers are on the approach chart, so no math included. Dead simple crosscheck, but not done.
.
The real question is, how on earth a pilot is starring on the NAV display watching the runway passing by.

"Hey skipper, we are there. Bring here down."
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Old 3rd Apr 2017, 08:39
  #349 (permalink)  
 
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waiting for a reasonable signal to return
This appropriate behavior for a system, but not for a pilot...
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Old 3rd Apr 2017, 15:17
  #350 (permalink)  
 
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Volume & Bleve,

So you're saying the system just defaults to a 3 degree path? What if you were flying a 2.5 degree glideslope? I have one such glideslope near me.

To be clear, I'm less concerned about the (in)actions of the crew, and more interested in the system logic.
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Old 3rd Apr 2017, 18:47
  #351 (permalink)  
 
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Hello Check Airman,

It is all a matter of careful wording, either in posts or in (reports about) reports.
In official Boeing documentation, there is a description of how the autoflight system monitors ILS signal for interferences, and how it will act to pass through such a phenomenon if it is short lived or if it persists. This description mentions that the system will maintain an inertial path, but does not attatch numbers to that description.

That description leaves room for interpretation and you can bet your 2 cents that the way the system works will be logical for the way an aircraft flies: if the ILS glideslope happens to be 3 degrees and, once established on the slope, the signal is lost for a short while, then the inertial path will be 3 degrees. If the slope was for 2.5 degrees, then the inertial path will be 2.5 degrees.

In this particular case, the aircraft started to intercept the 9 degree false glideslope - it never established a steady situation, the signal irregularity happened during slope acquisition. In that case, the most logical "best guess" inertial path would be 3 degrees, the "standard ILS slope" until a good quality signal would appear again. In this case, the inertial period lasted so long, that the proper warnings were given by the system, an AUTOPILOT Eicas Caution and AMBER LINE drawn through the pitch FMA. The proper reaction to those conditions is the immediate start of a Go Around.

You must realize that there is a lot of clever algorithm stuff in autopilot systems: for instance, most ILS glideslope intercepts are made from below the slope, in level flight - so you have a period where the ILS deviation would suggest to fly UP to the slope middle line. In reality, the A/P will maintain level flight until it hits the center of the slope.
A false 9 degree slope may exhibit a reversal of signal: fly DOWN when below the middle line, fly UP when above it. Whether or not the signal is reversed depends on the type of antenna array that is employed for the G/S signal. The A/P logic must filter and smooth all the signals and aircraft control commands so that no abrupt and illogical moves are made. The user manual descriptions will never be detailed enough to describe exactly how all that is accomplished.

What the user manuals do very well though is the bottom line - if things are not going in the way they should be going, GO AROUND! I mean, 1 mile to go to the threshold and being 2.000 ft above threshold elevation is a pretty simple indication that the situation is not as it should be.
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Old 4th Apr 2017, 08:26
  #352 (permalink)  
 
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This description mentions that the system will maintain an inertial path, but does not attatch numbers to that description.
But the Report does.
In the pitch chanel the A/P will maintain an inertial path which tracks a constant 3° slope regardless of the actual glideslope angle at a certain aerodrome
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Old 22nd Apr 2017, 13:07
  #353 (permalink)  
 
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Maybe it's been alluded to already ... but of the approach, had there been an observant check airman looking over the FO's shoulder during its conduct, what would he or she have said, and when would he or she had said it? And if that person had had an "attention getter" in their lap....say a short length of 2x4...at what point might they have used it?
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Old 22nd Apr 2017, 13:34
  #354 (permalink)  
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Certainly not less than 1,000 feet above touchdown elevation.
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Old 22nd Apr 2017, 15:02
  #355 (permalink)  
 
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Originally Posted by radken
Maybe it's been alluded to already ... but of the approach, had there been an observant check airman looking over the FO's shoulder during its conduct, what would he or she have said, and when would he or she had said it? And if that person had had an "attention getter" in their lap....say a short length of 2x4...at what point might they have used it?
What are the check airman's feelings who has signed the last check ride including low visibilty qualification?

I hope it wasn't kind of nepotism...
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Old 22nd Apr 2017, 15:04
  #356 (permalink)  
 
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And if that person had had an "attention getter" in their lap....say a short length of 2x4...at what point might they have used it?

I'm always amazed at people who sit there and watch as someone tries to kill them, not doing much. I'm lucky that it has happened very rarely; only the occasional moment my wife is driving and goes into a red-mist moment about some perceived misdemeanour of mine. There are no CRM skills dreamt of that can solve those moments. 2x4 in a confined space is difficult. Tasers might have the calming effect as we crash into whatever is in front of us; and the threat of same will be a bluff-calling standoff. Theory in a classroom is great, but in real life it somehow doesn't always work as planned. Not easy times, especially with cockpit gradients in some places getting very steep; and the monkey is not always in the seat you'd expect.
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Old 22nd Apr 2017, 16:02
  #357 (permalink)  
 
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Authority gradient?

With the proviso that we have no facts about the actual cockpit duties and interactions yet, the authority gradient issue assumption implies that that the Captain was at the controls and the F/O did not intervene. There is of course a very simple way to eliminate this situation.... have the F/O set up and fly the approach under the Captain's supervision, prior to the Captain confirming the landing, whether automatic or manual. As a broad generalisation, I suspect Captains are less likely to allow F/Os to kill them than vice versa.......

Leads hobby-horse back into stable .....
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Old 22nd Apr 2017, 16:06
  #358 (permalink)  
 
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Don't know ACT SOP, if any, but in my outfit CAT II/III is CPT's flying the auto.
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Old 22nd Apr 2017, 20:02
  #359 (permalink)  
 
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Originally Posted by slast
With the proviso that we have no facts about the actual cockpit duties and interactions yet, the authority gradient issue assumption implies that that the Captain was at the controls and the F/O did not intervene. There is of course a very simple way to eliminate this situation.... have the F/O set up and fly the approach under the Captain's supervision, prior to the Captain confirming the landing, whether automatic or manual. As a broad generalisation, I suspect Captains are less likely to allow F/Os to kill them than vice versa.......

Leads hobby-horse back into stable .....
Many years ago my company introduced such a task sharing for CAT II approach (those days CAT III was not available for our aircraft). F/O's job was to perform the approach - and the missed approach as well - unless at minimums CPT announced "Contact, I have controls". I really liked this as it eliminated the problem of CPT's incapacitation at low altitude.
Unfortunately it was on one aircraft type only for a limited period of time...
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Old 12th May 2017, 13:41
  #360 (permalink)  
 
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Isn't that the BA "Monitored approach?" It also has the advantage of eliminating the transition from clocks to visual reference. The monitoring pilot has the eyes adjusted to outside the cockpit and if he/she says, "Nothing seen, go around" the other pilot is already on instruments and simply performs a missed approach.

Done it both ways & I quite liked that system.
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