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PIA A320 Crash Karachi

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PIA A320 Crash Karachi

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Old 27th May 2020, 16:26
  #761 (permalink)  
 
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excrab, I believe they didn't talk to the Tower on the second attempt. After the go-around the Tower switches them to the Approach frequency. From that moment on they remained on that frequency until they crashed.
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Old 27th May 2020, 16:34
  #762 (permalink)  
 
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Originally Posted by excrab
As I said in an earlier post, it is a couple of years since I’ve been to Karachi, but every time I went there the tower controller always said something along the lines of “surface wind blah blah blah, cleared to land check gear down and locked” The problem is they generally cleared us to land well before intercepting the glide slope so we didn’t have the gear down and locked. But we never told them that, just acknowledged the clearance and followed our SOPs as to when configure for landing.
I think I read somewhere on about page 1000 of this thread that they didn’t talk to the tower, but even if they did, if they were told to “check gear down and locked”, and were regular visitors to Karachi they would possibly have been in the habit of ignoring the call anyway, even if they heard it.
I think you raise an interesting points about habits that may be formed regardless of the intent of the procedures in place. (Such as the tower reminding inbound planes to check gear ...).
Years ago I got the usual bottle of scotch (for stopping a gear up pass) from my flight student - he had gotten into the habit of reporting the gear down without looking to see. They usually were, but, on this occasion, he gave me three different reports of the gear down (and the flaps were down on the last two). But the gear indicators all said "up" - we were getting this little warning horn going off in our head sets. As he rolled final and reported his gear down the third time to me I instructed him to wave off (go around).

When pilots report the gear down, what process have we gone through to ensure ourselves that it is in fact down before we say the words? (I think that is what Pilot(DAR) was alluding to a few posts up).
If we are making the report as a reflex, or as you suggest, because the tower wants to hear it, then it sort of defeats the purpose.
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Old 27th May 2020, 16:36
  #763 (permalink)  
 
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As for the ATC part of the argument, who is flying the aeroplane? As it is, on the first approach ATC queried his altitude and hinted that he was high. The reply (on two occasions) was that it was in hand. Just what do you expect ATC to do? Furthermore, a Tower controller has much going on and is not following an aircraft all the way in. It is not unusual to look at an inbound when it still has the gear up and move onto other tasks until it is on the ground.
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Old 27th May 2020, 16:49
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As pointed out by DaveReidUK in #723, the Extended Mode S data from FR24 is garbage. I've seen "data integrity issues" before, but this takes the cake.

The question arises: Is there any way to salvage the data? I'm sure the cockpit data recorder and the tower tapes will be very informative, but I'm not holding my breath waiting for the authorities to release that data in .csv format.

FR24 claims "Overall trends in the data are correct as reported" but I beg to differ, as documented below. They also claim "Flightradar24 interprets this data using advanced scripts and historical comparative data" but evidently their Ouija board is missing a few letters.

In particular, consider the two records timestamped 2020-05-22 09:36:39Z.840 and 2020-05-22 09:36:45Z.880. Both are from FR24 receiver 1971. During this 6-second interval, the Mach number was unchanged, the IAS went up by 2%, and the TAS went down by 30%. Also the heading changed by 171 degrees, which is about ten times faster than a standard-rate turn. Also the OAT changed by 8 °C in six seconds. It's not a fluke in these two readings; multiple records from multiple receivers exhibit the same preposterous misbehavior.

Sorry, I do not consider these trends to be "correct as reported". Apparently the bit strings are being wildly misinterpreted. Many elementary cross-checks are not being performed.

They also claim that they need data from four receivers in order to calculate position. I'm pretty sure that's wrong too; three receivers plus pressure altitude should be sufficient.

So, bottom line: Is there any way of obtaining usable data?
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Old 27th May 2020, 16:50
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Not banging the ATC drum as such, but do you experts know how busy Karachi was on the day?
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Old 27th May 2020, 17:00
  #766 (permalink)  
 
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(pax). A bit disconcerted by the talk about using the gear to slow the thing down. Is that really an option in day to day ops and if you do it aren't there subsequent consequences since you shouldn't have been in that state anyway ( well so I assume). Thanks for your patience, I only sit in the back.
Perfectly normal. Gear often dropped early when intercepting the final approach with a tailwind, for example. It's most useful at about 200kts - the gear doors provide significant short term drag and can be what you need to get flap 2 out. I wouldn't consider using it from 10,000 ft because the speed brakes are more effective at higher speeds. The noise in the cabin is astronomical if you drop them anywhere close to the limiting speed.

Neither of the videos shown above seem plausible to me.
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Old 27th May 2020, 17:39
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Why is it every time a crash or serious incident occurs there are many calls to "automate" or "procedualise" out the suspected cause?

In this thread alone there have been calls for ATC to break off a suspected unsafe approach, for ATC to remind pilots to select gear down and I believe I even saw a suggestion to drop the gear automatically if it wasn't already down as the aircraft got below a certain height. Admittedly a lot of these ideas come from armchair critics and Flight Simulator specialists, but over time a lot of these types of ideas have found their way into the system in the name of safety.

Is it not the incorporation of all these so-called safeguards that point towards more of these types of accidents happening in the future?

The pilots get too reliant on the computer and gain very little appreciation of hand flying (and thereby aircraft charecteristics / limitations) as they are often required by SOP's to use the autopilot for the vast majority of the flight. If anything out of the usual comes up, rather than try to problem solve, in many cases I am sure the result is to "let the computer sort it out". Reliance on the computer then further results in loss of awareness, another incident may occur the computer is given an upgrade and the whole circle starts again.

Just me thinking aloud! back to my retirement now.
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Old 27th May 2020, 17:54
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Given their over speed at threshold, seemingly 215knots or so, what kind of flaps would the A320 even allow them to put out? Just slats maybe?....
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Old 27th May 2020, 18:02
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Originally Posted by ex-EGLL
Why is it every time a crash or serious incident occurs there are many calls to "automate" or "procedualise" out the suspected cause. In this thread alone there have been calls for ATC to break off a suspected unsafe approach, for ATC to remind pilots to select gear down
If you thought that was mad, you should have been here earlier - you missed the fitting of analogue gauges and my personal favourite so far - additional wheels on the bottom of the engines 'just in case'. I kid you not.
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Old 27th May 2020, 18:36
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Originally Posted by Joejosh999
Given their over speed at threshold, seemingly 215knots or so, what kind of flaps would the A320 even allow them to put out? Just slats maybe?....
Flap 1 which is slats only Vmo 230kt
Flap 2 is which is slat/flap Vmo 200 kt.
I thought that the telling item in the photo with the rat extended is that the wing is clean.As they turned downwind and declared Mayday where was the acceleration phase when they were rapidly running out of energy?
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Old 27th May 2020, 18:50
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I’d also wonder when the Gear Down decision came...presumably before they realized engines were compromised?
And how soon might RAT have deployed?
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Old 27th May 2020, 19:24
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Originally Posted by DaveJ75
If you thought that was mad, you should have been here earlier - you missed the fitting of analogue gauges and my personal favourite so far - additional wheels on the bottom of the engines 'just in case'. I kid you not.
Oh I saw them, but couldn't bring myself to repeat them!!
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Old 27th May 2020, 19:27
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In my humble opinion, it was a fast approach, with an overspeed of the flaps in short final, as heard on the ATC recording. That triggered the go around. The PNF may have retracted one step on the flap and raised the gear too early, making the aircraft sink on the rwy and scratching the engines before climbing out. The rest is a consequence of the damaged engines.
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Old 27th May 2020, 19:38
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Originally Posted by LookingForAJob
To be fair, the reason we do accident and incident investigation is to identify weaknesses in the system and to introduce fixes to to prevent recurrence..
No argument there, but in the vast majority of cases the fixes often turn out to be modifications to the aircraft systems rather than (re)educating the flight crews, thereby leading to more system reliance rather than maintaining and acting on pilot awareness. I'm sure many of you are aware of CVR transcripts with wording similar to "why did the aircraft just do that". The more time the pilots have to spend minding the computer the less they have for maintaining situational awareness.

Next bit being said (partially) tongue in cheek. Many moons ago when I first started in ATC,, once a week (or maybe month) the computer systems would be shut down for a couple of hours and everything progressed manually. No one was hurt, no one died but everyone knew how to do their jobs should the electrons stop flowing. I am not suggesting the same for pilots, but it may be worth having some form of basic principles brought back to the flight deck, even if it is hand flying from take off to TOC and TOD to the ground. Admittedly this may not be a good idea in highly congested terminal areas but I am sure it could be fitted in somehow.
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Old 27th May 2020, 20:10
  #775 (permalink)  
 
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Originally Posted by xetroV

With that speed over the threshold, I believe the crew would never have received a TOO LOW GEAR warning during the first approach; they would have received TOO LOW TERRAIN instead (or another mode if that would have priority). I can see how a crew would discard the latter GPWS warning as being erroneous/nuisance when approaching a runway in VMC, especially a crew that had already lost their situational awareness due to extreme (probably self-induced) tunnel-vision.


Here's the mode 4a envelope.
So, if the data that they crossed the threshold at 210 knots (and where still over 190 when engine nacelles impacted) is correct, they never would have gotten the "TOO LOW GEAR" warning - just the EPCS "TOO LOW TERRAIN" which could easily dismissed as a nuisance during landing.
Looking at the photo of the CFM56-5 Gearbox in post #728, given the rather high rate of descent during the pod strike - the gearbox casing almost certainly would have fractured (it's cast so relatively brittle). Best case, they would have lost nearly all the engine oil almost instantaneously. It apparently didn't do catastrophic damage to the gearbox internals since they would have lost the fuel pump and the engine(s) would have quit in a few seconds.
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Old 27th May 2020, 20:20
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Interesting thanks tdracer. If engines did quit in only a few seconds, assume RAT deploys?
And presume loss of thrust becomes apparent soon?

I’m just wondering when/why the Gear Down decision was ultimately made.
Possibly just a knee-jerk reaction when they realized (finally) that gear was Up all along? Ugh. What an awful moment.
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Old 27th May 2020, 20:30
  #777 (permalink)  
 
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Well spotted, xetroV. And excellent follow-up comments, tdracer.

Occasionally, just when one has had enough of the chaff, and is about to abandon pprune -- or a specific thread -- someone shines a light and brings renewed professionalism to the discussion.
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Old 27th May 2020, 21:05
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From an older FCOM

4B With Landing Flap, Full or 3, the "Too Low Terrain" will sound all the way down to 159Kt



Last edited by Milvus Milvus; 27th May 2020 at 21:17.
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Old 27th May 2020, 21:16
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Before everyone gets too excited, the post at 749 points out that the GPWS may not give an U/C warning but the ECAM will. They are different systems, and you can turn off the GPWS.
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Old 27th May 2020, 22:45
  #780 (permalink)  
 
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Originally Posted by tdracer
So, if the data that they crossed the threshold at 210 knots (and where still over 190 when engine nacelles impacted) is correct, they never would have gotten the "TOO LOW GEAR" warning - just the EPCS "TOO LOW TERRAIN" which could easily dismissed as a nuisance during landing.
Looking at the photo of the CFM56-5 Gearbox in post #728, given the rather high rate of descent during the pod strike - the gearbox casing almost certainly would have fractured (it's cast so relatively brittle). Best case, they would have lost nearly all the engine oil almost instantaneously. It apparently didn't do catastrophic damage to the gearbox internals since they would have lost the fuel pump and the engine(s) would have quit in a few seconds.
Speaking about acoustic warnings, and considering there were so many parameters out of limits, they may have gotten "SINK RATE , SINK RATE" , and "PULL UP, PULL UP" before the runway impact. Besides, there´s the ECAM , which surely was active with ¨"LANDING GEAR NOT DOWN" in red capitals and the MASTER WARNING caution flashing red and the chime sounding, But TUNNEL VISION is very powerful and blinding when the pilot flying is just trying to get the bird on the runway.
Anyway, my guess is that it won´t be long before CVR and FDR readings will be made available and it will be clear which warnings and in what order the pilot completely disregarded.
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