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-   -   734 hard landing @ Exeter (https://www.pprune.org/rumours-news/638130-734-hard-landing-exeter.html)

eagle21 20th Jan 2021 19:29

Not a good thing for West Atlantic loosing this hull after transferring so many aircraft to the spanish registry.

Alrosa 20th Jan 2021 20:04

Along with being one of the very few cargo airlines to make pilots redundant late last year citing “Brexit “ ...

DaveReidUK 19th May 2022 15:22

FDR traces from today's Final Report:

https://cimg9.ibsrv.net/gimg/pprune....1138d13a68.jpg



diginagain 20th May 2022 20:00

https://www.bbc.co.uk/news/uk-england-devon-61521046

tubby linton 20th May 2022 21:00

The report states the touchdown G was 3.5 which seems quite low for the damage that was caused.

DaveReidUK 20th May 2022 21:21


Originally Posted by tubby linton (Post 11232953)
The report states the touchdown G was 3.5 which seems quite low for the damage that was caused.

From the report: "The maximum vertical acceleration recorded by the FDR on touchdown was 3.8g, at this point there was 3° of left roll. However, FDR sample rates and sensor locations are not ideally placed to determine peak forces on touch down."

The fact that the touchdown was sufficiently hard to deform the LH MLG beam would appear to support this.

tubby linton 20th May 2022 22:13

I have read the report but a lot of other aeroplanes have touched down with a greater G with less damage.The report is a bit vague, perhaps the fdr data was poor, but it does mention a vertical rate in fpm on the wing box that exceeded the design tolerance Surely Boeing must have been able to work this into a G .It seems strange that it was not included. Reading the report it didn’t seem as factual or as well written as what we have come to expect from the AAIB and I have read a lot of them.

fdr 21st May 2022 04:43


Originally Posted by DaveReidUK (Post 11232453)

Thanks Dave for the info from the report. That was a fairly steady rate of shear throughout at a mild rate. Aircraft performance follows the attitude the pilots have placed the plane at... There is no obvious vertical flow occurring from a quick comparison of speed/attitude and derived VS. Crew would like to have those 30 seconds over again I guess. The cognitive load on a turbulent approach can get quite high, which is why the rules on stable conditions and the response to GPWS alerts is such an important input to the safe outcome of a busy little approach. A "pull up" in the flare is pretty much a good suggestion to the drivers. The 3.5 slope kind of sucks, that is going to always need a good stable finals to remain within reasonable limits for a heavy landing wieght, <900FPM or more for the stable slope....

stuff happens

p3:
"The commander recalled that as the aircraft crossed the threshold, at about 100 ft, the PF retarded the throttles, pitched the aircraft nose down, from about 5° nose up to 4° nose down, and then applied some power in the last few feet. During these final moments before the landing, there was another “SINK RATE” alert. The result was a hard landing. A “PULL UP” warning was also triggered by the GPWS, but it was not audible on the CVR."

Golly. Did he catch the #1 wire on the tailhook?

p9:
"There was no stated requirement in the OM for both pilots to monitor that the stable approach criteria were maintained below 500 ft, with the aim of delivering the aircraft to the point in space above the runway from which a flare manoeuvre will result in touchdown at the right speed and attitude, and within the touchdown zone. This is something other operators are known to have in their OM, with a requirement to conduct a GA if the stable approach criteria are not maintained to the landing".

An amendment to the FOM coming soon?

The OEM's FCTM for every type they make states a need to maintain stable flight path for the rest of the approach, an item that the report does note as well. If we are stable at 500' and inverted at 200' it is hard to justify the approach as being "stable" and consistent with the desired outcome of being able to reuse the plane and crew without rework or scrapping.

p16:
"The commander also stated that he felt it was too late for him to take control or call “go around” from about 100 ft RA."
That is pretty sad to see in writing coming from an experienced crew. Is there a magical figure where the plane suddenly doesn't do what it is supposed to? To save tire wear, we would routinely do a G/A at the start of a flare, in the flare (and at any point up to the selection of TRs) Years ago, the wisemen comment to the new 747 drivers is when all else fails, go wings level, 5 degrees nose up and all thrust that you can get... it may not be pretty but it is hard to hurt the plane in that condition, and it works for every Boeing other than maybe the 717 and 727. If we believe there is a latest point that we can do a go-around, then that needs to be dispelled. Presumably, the alternative is that at 100-RA we just give up as the outcome is preordained?

BoeingDriver99 21st May 2022 05:27

Is there a statement in their OM for both pilots not to crash? Or to keep their eyes open during landing? Or to keep breathing continuously? FML

Furniture Saver 21st May 2022 06:07

Fascinating that an 18-page report contains no explanation of why the co-pilot could not land the aircraft. This was the ‘cause’ of the accident (AAIB purpose: ‘…to improve aviation safety by determining the circumstances and causes of air accidents and serious incidents, and promoting action to prevent reoccurrence’) and deserved exploration.

WideScreen 21st May 2022 09:02


Originally Posted by DaveReidUK (Post 11232453)

Especially from (4), I'd say, the pitch input is lagging behind what is needed to get a stable descent rate. Not completely anti-cyclic, but the corrections are sufficiently delayed and being too big, making it impossible to dampen the inherent GS deviations. Which in turn suggests a lagging brain, which in turn might suggest fatigue.

A Go-Around and next landing may have suffered from the same problem, fatigue doesn't go away.

DaveReidUK 21st May 2022 11:28


Originally Posted by Furniture Saver (Post 11233100)
Fascinating that an 18-page report contains no explanation of why the co-pilot could not land the aircraft. This was the ‘cause’ of the accident (AAIB purpose: ‘…to improve aviation safety by determining the circumstances and causes of air accidents and serious incidents, and promoting action to prevent reoccurrence’) and deserved exploration.

That's a tad unfair on the AAIB. While it doesn't specifically use what the NTSB terms "probable cause" and "contributory factors", the section in the report labelled "Conclusions" is pretty unambiguous:


"The aircraft suffered a hard landing as a result of the approach being continued after it became unstable after the aircraft had past the point where the crew had declared the approach stable and continued.

Despite high rates of descent being observed beyond the stable point, together with associated alerts the crew elected to continue to land.

Had the approach been discontinued and a GA flown, even at a low height, while the aircraft may have touched down the damage sustained may have been lessened.

While the OM did not specifically state that an approach was to remain stable beyond the gate on the approach, the FCTM was specific that, if it did not remain stable, a GA should be initiated.

The commander may have given the co-pilot the benefit of doubt and believed she had the ability to correct an approach that became unstable in the final few hundred feet of the approach.

However, had there been any doubt, a GA should be executed."
Without the ability to get inside the heads of the crew, what more would you like to have seen?

fdr 21st May 2022 15:37


Originally Posted by Time Traveller (Post 11233205)
In recent years I've encountered new pilots who have extraordinary perceptions, which they say they were taught during training - about how to salvage a landing which is going a bit pear shaped.
One is to add a surge of thrust just prior to touchdown; normally that's just makes for a very fast and long touchdown, and sometimes PIO in the past couple of feet trying to force the gear to touch.
And the worst - to actually push on the yoke when coming down too fast!!! Now this lead to the only hard landing I've ever been the crew for. And a sudden push at 20' is almost impossible for the captain to catch! He swore blind a trainer taught him this; of course it's crazy. (I think it comes from the theory in long wide bodies, where I tiniest relaxation of the back pressure at about 2' was the way to get a super smooth touch (it does), and he claimed he was told increasing pitch slightly pushes the gear towards the runway making it worse - nonsense of course - the mains are close to the pitch axis, and that effect is dwarfed by the massively increased touchdown descent rate by pushing) - No!; faced with excessive sink rate crossing the threshold - flying 101 ... PULL to moderate the descent rate (if the speed is adequate) ... or go around.
Anyway, both elements seem to be in this incident.

It is a nasty little technique.... it has remained around from the MD80 and B727 which could benefit from an initial flare and then a slight de-flare. The risks on the method are enormous, Doing an analysis of what the wheels sink rate does in a de-flare gives zero comfort as a procedure to avoid a hard landing. forward stick may help a P51 or T6 wheel landing to plant the gear, but otherwise is high risk.



Furniture Saver 21st May 2022 23:27

Dave, some exploration at least as to why an experienced but possibly borderline-competent pilot was not able to land an aircraft. Fatigue? Insufficient cues? Distraction? Fundamentally unsound technique? There’s simply no effort to explain it. The AAIB costs somewhere around £8M a year, and really should be doing a lot better than that.

lederhosen 22nd May 2022 05:48

Text book example of why you should go around when an approach becomes unstable. Interesting how many hours the co-pilot had; 19,000 with 5,000 on the 737. The captain had 15,000 with 9,000 on the aircraft. I also wonder why the co-pilot did both landings, particularly in somewhat challenging conditions at an airfield the company later designated captain‘s only for landing. The captain had only flown 25 hours in the last 3 months so presumably could have used the practice. Middle of the night, Covid impact on currency, company disruption potentially also distracting the crew, made for a number of holes in the Swiss cheese.

excrab 22nd May 2022 09:02

Looking at the experience levels I wonder if these were two Captains flying together perhaps, although not mentioned in the report. Seems strange that a pilot with that experience and time in the company would still be an f/o, when you consider that 3000 to 4000 hrs is a typical experience for 737 Captains at some low cost carriers.

EcamSurprise 22nd May 2022 09:10


Originally Posted by excrab (Post 11233563)
Looking at the experience levels I wonder if these were two Captains flying together perhaps, although not mentioned in the report. Seems strange that a pilot with that experience and time in the company would still be an f/o, when you consider that 3000 to 4000 hrs is a typical experience for 737 Captains at some low cost carriers.

In my airline you get two shots at command and then you’re out of the process. Having many hours doesn’t automatically mean you are suitable to be a captain. If anything, having such high hours as an FO often tells a story in itself.

Akrapovic 22nd May 2022 09:22


Originally Posted by excrab (Post 11233563)
Looking at the experience levels I wonder if these were two Captains flying together perhaps, although not mentioned in the report. Seems strange that a pilot with that experience and time in the company would still be an f/o, when you consider that 3000 to 4000 hrs is a typical experience for 737 Captains at some low cost carriers.

Perhaps the report in question goes a long way to explaining that. . . . . .

Alrosa 22nd May 2022 11:03

The bulk of the FO’s hours were most likely obtained elsewhere - accumulating those kinds of hours at an operator like WA is impossible. The norm I believe was 1 week on/1 week off with no more than 2-3 sectors a night.

Fair_Weather_Flyer 22nd May 2022 12:13

For me, the report did not really drill into the underlying reasons for the accident. Given that this report was 18 months in the making, I thought that it would be very detailed. The NTSB reports like to track the history of the pilots in their earlier career, through their recruitment into the airline and their detailed training history within the airline. Failed checks and commands etc are fair game.

My own unfortunate experience is that airlines have a dirty little secret of a group of poor pilots. How big this group is depends on sound recruitment, training and a plan of how to deal with those who are not able to meet standards. The slightly steep, Exeter, approach should not be a very challenging one, especially for a 19000 hour pilot. I'd bet that these pilots had a long history of poor performance dating over many years and various airlines. How they were recruited and why the airline did not act over the FO remains a mystery. What can we learn from such a mystery?


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