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You only need to watch and hear the Air Niugini crash video to understand what can be ignored by a crew under pressure. Well ignored or disregarded.
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Originally Posted by mr ripley
(Post 10791751)
Re Belly landing quote from ATC?
How about, because the pilot has just announced both engines have failed, thus ATC thinks they are going to do a crash landing. |
The last Aviation Herald update adds some more indications that the first landing attempt was made with landing gear up:
On May 24th 2020 Pakistan's media quote a CAA official speaking on condition of anonymity that the aircraft made two attempts to land. During the first approach it appears the landing gear was still retracted when the aircraft neared the runway, the pilot had not indicated any anomaly or emergency, emergency services thus did not respond and did not foam the runway as would be done in case of a gear malfunction. The marks on the runway between 4500 feet and 7000 feet down the runway suggest the engines made contact with the runway surface, it is possible that the engines were damaged during that contact with the runway surface leading even to possibly fire. On May 24th 2020 a spokesman of the airline said, the landing gear had not been (partially or fully) lowered prior to the first touch down. The crew did not call out the standard operating procedures for an anomaly and no emergency was declared. Most likely the crew was not mentally prepared for a belly landing and went around when they realized the engines were scraping the runway. |
They probably do but being official would be for the investigation and not released into the public domain. (unless someone leaks them). Or the system was broken. That would make sense but I have to say I have yet to see any evidence of such either in the narrative of any official accident report or any screenshots etc. I would have thought such evidence would be invaluable to investigators. |
Originally Posted by mr ripley
(Post 10791751)
Re Belly landing quote from ATC?
How about, because the pilot has just announced both engines have failed, thus ATC thinks they are going to do a crash landing. |
Is it possible that the gear could have been lowered early, out of normal sequence, to increase drag, then retracted instead of lowered at the point where it would normally have been lowered?
FBW |
Originally Posted by Teddy Robinson
(Post 10791569)
The Smartlynx A320 incident at Tallinn 28th Feb 2018 has been mentioned previously on this thread.
Whilst an underlying technical issue led to the main event (aircraft contacted the runway once the gear had been selected up), both engines subsequently failed shortly thereafter. None of that probably has anything to do with the thread accident, but it's important to note that a “technical issue” was not even close to the only cause of the Tallinn accident you linked. |
Why has there been so little comment on the fact that they were offered a 360 degree orbit to lose height on the original approach. "Turn left onto 330 ..." (i.e attacking heading to regain the localiser )?
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There’s mention that they might have lowered gear levers at too high a speed, such that protections did not allow gear to go down. Lever would have to be recycled and speed reduced first.
So they thought they had gear down, but didn’t. Possible? |
Originally Posted by Dropp the Pilot
(Post 10791519)
Two wrong statements in less than twenty words - pretty impressive even for a thread which is wanna-bee infested to a degree not often seen.
Neither of these things are "positive rate". A V/S trend is a measure of vertical acceleration. It will happily read a positive vertical rate with both main gear planted on the runway with say, a gross error in take-off performance calculations or wind shear. RA is valueless for rate as the reading which the pilots see is a product of an algorithm of pitch attitude and gear tilt and is by no means a direct reading of actual height. The ONLY measure for positive rate is a sustained and progressive increase in the altitude displayed on the altimeter. Should you doubt any of this, consult any FCTM from a company called Boeing. They've been doing this stuff for quite some time. Boeing do not refer to rate; they refer to climb - on the altimeter. Yes, yes, feel free to check any Boeing manual however if you want relevant information on this event may I suggest you try something written by Airbus. |
Originally Posted by Airbubba
(Post 10791508)
From 35k to 10k ft in <13minutes. And then from 10k to 2k in less than two minutes. Somehow this f*ck up bgean to start already back at 35k. And from 10k on it became worse. How on Earth did they think they would dissipate all that energy?! OK by putting out the flaps above VFE. But surely can't have been the plan!? |
Originally Posted by scotbill
(Post 10791929)
Why has there been so little comment on the fact that they were offered a 360 degree orbit to lose height on the original approach. "Turn left onto 330 ..." (i.e attacking heading to regain the localiser )?
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Some notes taken from various Pakistani press sources:
Both recorders were found on Friday. The FDR will be read in France by the BEA. There will be at least three independent investigations. The first by the Pakistani AAIB. The second by the Pakistani military. The third by Airbus (Note A0283: that would be unusual, they probably mean that Airbus will be a party to the safety investigation - but they focus on the independence). There are 2 certain survivors from the plane, both named males. There is one note of a named female survivor (Note A0283: which was on the published passenger list, and not being the named female model which was mentioned in earlier reports). One official source shows 1 dead and 4 injured on the ground. About the aircraft: Aviation authorities on Saturday released an executive summary of the aircraft, revealing certain facts about its maintenance and operations history. According to the summary, the Airbus A320-214 aircraft was 16 years old and up till now, had flown for 47,124 hours. The aircraft’s last flight before Friday’s ill-fated one between Lahore and Karachi, took place just a day ago when it ferried Pakistani citizens stranded in Muscat to Lahore. The aircraft last underwent a routine check on March 21 of 2020 and major check on October 19 of 2019. Although it was grounded between March 22 and May 7, this was on account of Covid-19 and not for any airworthiness issues. The summary stated the aircraft suffered from no engine, landing gear or major aircraft systems defects and had operated 6 flights since being pressed back into service on May 7. Both of the aircraft’s engines were installed last year in February and May. Its landing gear was installed in October 2014 and was due for removal and overhaul in October 2024. |
From elsewhere...
"If you lower the L/G above 260kts, the L/G Safety valve will prevent the Green HYD from lowering the gear, but the L/G Lever will go down. Now once below 260kts, will the L/G come down on its own? Or does the Lever need to be recycled?" That's a very good question. If we believe an old FCOM, the lever has to be recycled to get the gear down below 260kts. The valve won't open if the lever just stays down when the speed goes below 260kts. That would be a very good explanation for the gear up landing (lever down at high speed to increase drag, but gears stay up). Then the alarm priority kept the "too low gear" off until flare, to late to avoid contact... |
If the airline spokesman quote is accurate, the pilots are being hung out to dry. There must be very limited circumstances where the gear was still up but no warnings sounded.
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Originally Posted by krismiler
(Post 10791804)
Even one warning during an approach is bad enough and suggests that a go-around would be a good idea.
Fear of loss of face from going around may well have played a part, culturally it may only be acceptable for the senior pilot to decide whether to continue, and unsolicited advice from a junior would be regarded unfavourably. When CRM is really bad it might even cause the senior pilot to feel he has to prove a point and establish his authority. With engine bypass ratios becoming higher and ground clearance being reduced, has adequate consideration gone into the location of vital components such as pumps, gearbox’s and supply lines ? Whilst space is obviously constrained, having vital systems in a vulnerable position should be avoided. presumptive design is typically based on historical experience. Things to do with oil loss or maintenance errors are mitigated by placing the gearbox and other accessories under the engine. Severe pod scrapes followed by continued flight are relatively rare in comparison |
Originally Posted by Milvus Milvus
(Post 10791987)
That would be a very good explanation for the gear up landing (lever down at high speed to increase drag, but gears stay up). Then the alarm priority kept the "too low gear" off until flare, to late to avoid contact...
Interesting scenario. But they surely would not get three greens? That being sais in the confusion they might also have missed that cue |
Originally Posted by atakacs
(Post 10792000)
Interesting scenario. But they surely would not get three greens?
That being sais in the confusion they might also have missed that cue Also, even with the Gear Up they would get the ECAM WHEEL PAGE at 800ft on the Lower Ecam along with six Red Triangles to show wheels up. It would mean no Landing Checks carried out either. In the Circumstances, although all this seems remote it could just happen. |
Originally Posted by EFHF
(Post 10791927)
None of that probably has anything to do with the thread accident...
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Originally Posted by EFHF
(Post 10791927)
That's accurate if the main event is considered to have been the EFCS pitch control failure. If with main event you mean the wheels in transit ground contact, then the report makes it quite clear that the EFCS failure led to the crew failing to control pitch proparly for 36 seconds as they didn't understand at all that pitch was in manual reversion through the THS control with the trim wheel. The report also speculates (altough doesn not test that hypothesis) that ground contact would still have been avoided without the unexplained selection of idle thrust for 4 seconds before the ground contact.
None of that probably has anything to do with the thread accident, but it's important to note that a “technical issue” was not even close to the only cause of the Tallinn accident you linked. TR |
Originally Posted by Milvus Milvus
(Post 10791987)
From elsewhere...
"If you lower the L/G above 260kts, the L/G Safety valve will prevent the Green HYD from lowering the gear, but the L/G Lever will go down. Now once below 260kts, will the L/G come down on its own? Or does the Lever need to be recycled?" That's a very good question. If we believe an old FCOM, the lever has to be recycled to get the gear down below 260kts. The valve won't open if the lever just stays down when the speed goes below 260kts. That would be a very good explanation for the gear up landing (lever down at high speed to increase drag, but gears stay up). Then the alarm priority kept the "too low gear" off until flare, to late to avoid contact... FCOM says to recycle gear handle in that situation. The CRC can be silenced and the ECAM can be cleared purposely or inadvertently. A few years back I had an airplane where the safety valve stuck in the closed position. To say the least it was quite a shock when I called for Gear down to the FO and it failed to come down. I don’t know how any pilot could miss that cacophony and light show. At the time the procedure was to recycle the gear handle up to five times. On the third try it came down. i don’t think in this case that happened. |
Originally Posted by henra
(Post 10791949)
Wow!.
From 35k to 10k ft in <13minutes. And then from 10k to 2k in less than two minutes. Somehow this f*ck up bgean to start already back at 35k. And from 10k on it became worse. How on Earth did they think they would dissipate all that energy?! OK by putting out the flaps above VFE. But surely can't have been the plan!? |
Originally Posted by FatPilot
(Post 10791943)
Numerous wrong statements in that post including a misunderstanding of the RA system AND the IVSI.
Boeing do not refer to rate; they refer to climb - on the altimeter. Yes, yes, feel free to check any Boeing manual however if you want relevant information on this event may I suggest you try something written by Airbus. Hopefully, we may learn some things... IMHO the ONLY RELIABLE INDICATION that should be looked at and followed is an INCREASE in ALTITUDE ON the ALTIMETER, which confirms a ”POSITIVE CLIMB !” So, forget the VSI (and all others…) and look at the ALTIMETER ! It’s a paradox… Just ask a pilot: ”Where do you see that you are climbing?” And 9 out of 10 will reply: ”On the vertical speed indicator!” Hence: That’s where most are looking… At the VSI. (However, the VSI is used for establishing or maintaining a certain rate of climb or descent…) Whilst it is that simple, Still nowadays it takes me numerous briefings and sessions, and almost every half year I have to repeat it, to try to really ’delete’ the call: ”positive rate !” from the brains of experienced pilots, coming from everywhere and from different established airlines, flying Airbus and Boeing and others... Even when they ’seem’ to understand all the issues involved. It’s just because for many ’rate’ has been ’slammed into’ their minds during their very first flying lessons, (as was done to me in the early ’sixties’) their eyes are looking at the wrong instrument… (A totally different, but similar issue is 'deleting' the "Ready for take off !" call, to be replaced by: "Ready for DEPARTURE !" ...) Just always learning, learner . . . ;) |
That's a very good question. If we believe an old FCOM, the lever has to be recycled to get the gear down below 260kts. The valve won't open if the lever just stays down when the speed goes below 260kts. If they were 5nm out and going so fast that the landing gear couldn't extend it's unbelievable that they continued, even if they had been on the correct vertical profile they were around 100kts too fast. With the recorders available and being read by French investigators, together with the marks on the runway we should have an accurate sequence of events fairly soon and won't have to speculate on what happened. We can instead look at WHY it happened. |
Reference the 1st approach, allowing to get hot and high by whatever means at five miles, could the crew have decided to ‘chase the profile’ by converting to a visual approach?
Yep they should request/advise ATC That’s what they’re doing, but already behind the curve would that change of procedure mean an increased cockpit workload. I’m thinking in terms of cancelling alarms and warnings possibly already active from the position if the aircraft was being flown assuming an ILS. Would a gear up warning Gpws be cancelled in that scenario? If so and target fixated, working hard to achieve what they already know will be a challenge to complete a ‘hot’ landing, could a gear warning be overlooked or misheard in that scenario?, and the gear subsequently not selected. |
From the Boeing FCTM:
‘Retract the landing gear after a positive rate of climb is indicated on the altimeter.’ So if my company wants me to say ‘positive rate’, that’s fine by me. Yes, I do know that I need to look at the big white needle going clockwise or the alt tape numbers scrolling upwards. Out of interest, as a non Bus driver, what does their FCTM equivalent say? |
Nah. Semantics really.
”positive rate” as said in many SOP’s around the globe, simply means that a positive rate of climb has been established. It is the abbreviated form of “positive rate of climb”. Same as: “gear down, flaps 20”, which means “select the gear lever down and subsequently select flaps 20, please” Let’s not get into this. Just make sure you do a go-around when too hot and high. |
So far then, appears aircraft approach was not ideal yet decided a bit late to go-around. By that time aircraft engine cowls had "touched" the runway, too much speed and not enough runway left so decided on a second approach not realising that the AGB's were not functioning normally. Moral of this may be - get your approach criteria correct including flap position and gear extended before decision height. Two captains and they could not get this right.
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Originally Posted by giggitygiggity
(Post 10792044)
The second half of that aside. Is 35k to 10k in 13 mins that incredible? 25,000 ft to lose in 13 mins, ~2000ft/min?
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Originally Posted by krismiler
(Post 10792054)
If they were 5nm out and going so fast that the landing gear couldn't extend it's unbelievable that they continued, even if they had been on the correct vertical profile they were around 100kts too fast.
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Originally Posted by henra
(Post 10792075)
It is surely on the high side. Would have been OK if they had space to dissipate the energy for the final approach. But with that descent rate even with engines at idle you will arrive at 10k on the high side of the speed range. And in this case at 10 kft they were so close to the airport that they had to even further steepen the approach. So looking at that graph it indicates that they probably started the descent a few minutes too late for the given circumstances. For whatever reason. Possibly they were expecting a holding pattern or a much wider circuit?
This is not a boast and I'm sure you'll label me as an accident waiting to happen, but I looked up the last flight I did on the A320 to Tenerife (sadly back in march), I descended from 39,000ft to 10,000ft in 11 mins after getting a very nice (and requested) short cut from ATC - 2,600ft/min average. I managed to land without crashing into Las Americas. There was however just (again sadly) 6 of us on board. |
Thanks Aviation Herald.
So it did do a double pod scrape with the gear up, that will very probably have destroyed the IDGs and hydraulic engine driven pumps. AC1 and AC2 probably lost, hence RAT deployment. B HYD system only. Since the gear is down, we're straight into direct law, protections lost. That would be a very challenging configuration for a good crew to fly on their lucky day, for the initial baulked landing and of course the subsequent approach. Apparently high nose attitude in the final video would suggest an attempt to stretch the glide, with obvious results. |
From the point of view of 'Human Factors'
1. The first is observed when the crew says that they are comfortable at 3500 feet at 5 miles. Here the crew is getting self trapped into being committed for landing 2. Second is when they announce that they are established on ILS, which they are not. Making such announcements would put lot of pressure on the crew to somehow push through the landing. Ego could also have been triggered here. Still, the landing could have been hacked but for the fact that the gear was missed. This resulted in irretrievable situation. Tunnel vision and get homeitis have a role. Such mistakes though not common do happen. Here the crew were unlucky to have additional and overlooked problem of gear. |
Originally Posted by giggitygiggity
(Post 10792102)
It might perhaps be slightly on the high side but calling it incredible is somewhat sensationalist.
This is not a boast and I'm sure you'll label me as an accident waiting to happen, but I looked up the last flight I did on the A320 to Tenerife (sadly back in march), I descended from 39,000ft to 10,000ft in 11 mins after getting a very nice (and requested) short cut from ATC - 2,600ft/min average. |
Originally Posted by henra
(Post 10792129)
They had to steepen the aproach further and apparently couldn't get rid of the energy which in turn may have occupied them so much that it may have contributed to them making a very basic and stupid mistake.
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3500 ft at 5NM is not doable in an A320. If you want to try, you need to start with gear down and flaps full. Still you will end up with an increasing speed. More so if you do this without gear down.
Every professional pilot knows this. So, why did they try? What caused such a major breakdown in common sense? And why are we not allowed to talk about the elephant in the room (or cockpit)? |
Originally Posted by henra
(Post 10791949)
Wow!.
From 35k to 10k ft in <13minutes. And then from 10k to 2k in less than two minutes. https://cimg5.ibsrv.net/gimg/pprune....db311bdb32.jpg They descended through FL100 at 09:30:18Z: https://cimg2.ibsrv.net/gimg/pprune....dd18493dc6.jpg Descending 24000 feet in 14:31 gives a little under 1700 feet per minute, fairly reasonable I would say. Check my math(s), like timezones, this stuff is easy (for me) to mess up. On the other hand from FL100 to FL19 (these Mode-S altitudes are all referenced to QNE so the differences should be right even though corrections need to be added for QNH and QFE altitudes) looks like 162 seconds to lose 8100 feet or about 3000 fpm. https://cimg8.ibsrv.net/gimg/pprune....0b245b6fef.jpg DaveReidUK posted this plot of the altitude data for the last few minutes of the flight: https://cimg4.ibsrv.net/gimg/pprune....caa3d77a16.jpg And unworry posted this plot with a derived rate of descent: https://cimg8.ibsrv.net/gimg/pprune....6e8c164eb6.png |
IMHO the ONLYRELIABLEINDICATION
that should be looked at and followed is an INCREASE in ALTITUDEON the ALTIMETER, which confirms a ”POSITIVE CLIMB !” So, forget the VSI (and all others…) and look at the ALTIMETER ! Totally agree. You watch the VSI at rotate. Disturbed static air. The VSI gives erroneous readings, albeit momentarily. . Watch the VSI when the gear doors open and close. If you saw that you wouldn't rely on a vsi again, for positive climb. Notice i stated positive CLIMB, not rate. |
Originally Posted by Greek God
(Post 10791815)
With regard to this particular event and many more I have long wondered why Towers (especially at major airports) do not seem to have continuous CCTV coverage of every approach and threshold.
Also, in the absence of any notified emergency, should it not be SOP that the ATCO called a GA for a commercial airliner on short final with no gear? |
Originally Posted by Airbubba
(Post 10792151)
Descending 24000 feet in 14:31 gives a little under 1700 feet per minute, fairly reasonable I would say. Check my math(s), like timezones, this stuff is easy (for me) to mess up.
OK, 1700fpm seems reasonable. That should be roughly what an A320 does in flight idle. |
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