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Pegasus accident in SAW; just reported

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Pegasus accident in SAW; just reported

Old 6th Feb 2020, 13:29
  #141 (permalink)  
 
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Re: the 10 or 15 knot tailwind limit:
737NG: We had a 10 kt limit. Sometimes we lended an airframe to one of our sister airlines, which has a separate AOC. The plane wasn’t even painted over, just some paperwork was changed. Suddenly this same airplane was now allowed a 15 kt tailwind! That simple.
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Old 6th Feb 2020, 13:41
  #142 (permalink)  
 
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Originally Posted by EDLB View Post
It is not, that you physical can not land with higher tail winds. The problem is that the ground speed is the tailwind component higher than your IAS (Which makes your airplane fly).
So the normal 3 degree slope will need to be less than 3 degrees and you run faster out of runway because your touch down speed is by the tailwind component higher. So you need a longer runway, the slope should be lower than 3 degrees which often terrain clearance, noise abatement, ILS slope and procedures do not allow for, and your touch down ground speed is higher, which might be limited by tire rating and breaking performance.

The theoretical lower than 3 degree slope needed for tail wind also mean, if you are high on a 3 degree slope with tail wind, forget it. You need much more runway with tail wind and if you touch down late...
No. The glideslope remains the same as long as the throttles can stay above idle to prevent IAS from increasing. The only thing tailwind does is to increase the groundspeed at which you touch down and that higher groundspeed causes the longer landing distance required. Combine that with landing out of the touchdown zone (long) and the runway will quickly become too short.
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Old 6th Feb 2020, 14:08
  #143 (permalink)  
 
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Originally Posted by EDML View Post
There wonĎt be distances in the manual for TW much higher than allowed.

However, with 3000m I am sure it would have worked using all of the runway. They left the runway with around 60kt. 500m more and they easily would have made it.
Operational landing distance is 2539m acc. Boeing OPT (TALPA, 455m flare, +15%)

SAW, RWY06, BA medium, Max LDW, GND speed 174kts
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Old 6th Feb 2020, 14:58
  #144 (permalink)  
 
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However, with 3000m I am sure it would have worked using all of the runway. They left the runway with around 60kt. 500m more and they easily would have made it.
Roughly 65% higher energy than the same landing with a 10kt headwind.
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Old 6th Feb 2020, 15:20
  #145 (permalink)  
 
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Originally Posted by ProPax View Post
<snip>
In 1997, ICE high-speed train at Eschede derailed at 200kph on a flat track, piled up, threw the pile-up into the bridge, collapsed it and killed 101 people injuring 80 more. In 1993, a much older TGV train derailed at 300kph due to a hole opening under the track, stayed upright, and produced one light injury. Which one was a better design?
If i ever need an example for over-simplification, here it is. When the TGV derailed, was there as switch (point) on the track? Was there a bridge in the way?
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Old 6th Feb 2020, 15:27
  #146 (permalink)  
 
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Originally Posted by wtsmg View Post
Anyone at work with access to 73 landing perf? 22-37kt TW, braking action good or medium to good, 3000m rwy, ZFW for 177 pax, probably <2T fuel.
I doubt you'll even get Boeing to calculate such landing performance for you, because it is extremely unlikely 737 was ever landed with 30kts tailwind during test programme.

Our AFM data is only up to 15kts.
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Old 6th Feb 2020, 15:42
  #147 (permalink)  
 
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Originally Posted by FlyingStone View Post
Our AFM data is only up to 15kts.
There has to be some consideration... you can land with 15 kts reported wind, with gust up to 24 kts not reported.

And eventhough you get a mean wind of 15 kts reported, you will not be updated on the wind, unless the mean wind gets to 25 kts.... if you get the idea?
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Old 6th Feb 2020, 15:47
  #148 (permalink)  
 
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Originally Posted by Kirks gusset View Post
the trust levers advanced, which is possible if the aircraft lands in TOGA mode
It did. CM2 as PF innitiated go-around, CM1 took over and landed but never disengaged the autothrust. Not a whole lot of imagination is needed to realize what happens when reversers are stowed not quite at the same time.

If you have just joined the discussion, Kirk's gusset and I are referring to Jan 2018. TZX messup.

Originally Posted by parkfell View Post
Airport design also a critical factor.
How so?

Originally Posted by fox niner View Post
Whatever has happened, we will never know exactly. Turkey does not publish ANY accident reports.
That actually depends on the definition of "to publish". It's true the accidents investigations results are not made public. A few hardcopies are made and disseminated to parties including the airline, the manufacturer and the authority of the registry. I really, deeply don't like it but seemingly it satisfies the letter of ICAO rules.

Originally Posted by tdracer View Post
On a more serious note, maybe it's time for some airports to look into installing EMAS
Sabiha GŲkcen has 3000x45 m runway built on a hill so steep decline at about 100m past THR24 is there because the last part of runway 06 is actually built on embankment. It's all very nice having an EMAS but personally I would prefer not getting runway shortened because of it.

Originally Posted by Double Back View Post
Interesting. In my B744 days I showed many a F/O, during X-wind landings, how the wind vector on the ND or PFD changed dramatically as soon as the PF decrabbed the beast, or when the A/P decrabbed it. I told them to stop reading the wind out loud as it only brought false info.
Wow. I am utterly impressed with your VSOP* technique of having both of you looking at ND wind display during landing flare. Being far lesser airman than you, I am reduced to arriving to 50 ft over the runway at proper place, with proper speed and proper thrust and relying on visual cues, e.g. touchdown zone fleeing away laterally and/or longitudinally from my aeroplane at an unacceptable rate, to judge whether to plonk it or to escape vertically, in the direction contrary to local gravity. Also I am so unaware that ND wind is false that I still try to use it as an assistance in possible windshear detection. I can only hope that, through experience, I'll become more like you.

*VSOP = Very Superior Old Pilot, an aeronautical being whose depth & breadth of knowledge of the matters pertaining to flight, acquired through experience, are of almost mythical proportions and who is only too happy to impart the aforementioned knowledge on any suitable target, main suitability criterium being position in the hearing range. He usually knows the cure for all our contemporary aeronautical ills, primarily consisting of returning to standards and procedures of the times when we lost the plot and working our way from there but in the right direction. Alas, for all their strength, his opinions are rarely taken into account and I'd daresay that's one of the major reasons we have the safety statistics the way we have them today.

Originally Posted by EDLB View Post
Will be an interesting CVR to see how the decision making process went on.
Chances of CVR ever making it to public are poor to nil.

Originally Posted by 73qanda View Post
Is it just me or has the NG had more than itís fair share of over-run events in the last decade?
Probably just a statistical glitch. I found 738 faster down the glide and more slippery than 320 but still well within "easily manageable" area.

Originally Posted by Joe le Taxi View Post
A question I expect Boeing are starting to ask themselves is, is it good business sense to sell our products to airlines who are given to smashing them to pieces, putting them on front pages and giving regulators palpitations?
That was already pre-empted by stopping the deliveries of MAX to any airline whose inferior pilots' performance might tarnish the reputation of Boeing's superior aeroplane.

Originally Posted by Ollie Onion View Post
I assume there was not a lot of fuel onboard as there was fire at the breakup but is seems to have extinguished itself which would suggest not too much fuel in the tanks which may have forced the issue of pushing on with such an tailwind.
SAW was the destination, they absolutely needed to have at least alternate fuel plus half an hour in their tanks at landing. Dunno what was their alternate but LTFM accepted post-crash diversions pretty swiftly and efficiently. At that time Bursa was affected by the TS and quite unusable but «orlu or Eskişehir are not far away either.

Originally Posted by Kirks gusset View Post
Although SAW is often closed at night for "repairs" it appears nothing actually gets fixed, the airport stopped the heavy cargo aircraft for a while, but that didn't help much. In truth the runway needs digging up and completely re-laying.. just like Gaziantep, although hopefully quicker.
The problem with Sabiha is that, unlike GZT, ADB or ERZ, taxiway D is really a taxiway and can't be used as a runway while main one is being repaired. SAW has become a victim of its own success (mainly brought on by Pegasus) as the original plan called for far less movements than there were in a last decade so the runway is really beaten up. The new parallel runway is being built but I don't hold much hope for it to get operational this year. Anyway, all the unevenness of the runway and too much tire deposit in the TDZs, did not significantly affect the result of landing about 2 km into 3 km long, wet runway, with tailwind above limit.
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Old 6th Feb 2020, 16:23
  #149 (permalink)  
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Do we know if the cockpit crew survived? I note that the first section of fuselage is upside down but essentially intact but for the underside/nosewheel area damage.
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Old 6th Feb 2020, 16:26
  #150 (permalink)  
 
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Originally Posted by PJ2 View Post
Do we know if the cockpit crew survived? I note that the first section of fuselage is upside down but essentially intact but for the underside/nosewheel area damage.
copilot, dutch, is in hospital.
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Old 6th Feb 2020, 16:42
  #151 (permalink)  
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Thank you, sleeper. Any word on the captain?
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Old 6th Feb 2020, 17:18
  #152 (permalink)  

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3 Runway Excursions in 2 years

The simple statistics for PGS alone need no embellishment. Other national airlines have contributed to the accident record. Reviewing the high frequency of accidents involving Turkish passenger carriers, one must conclude that there is an inherent problem.

The recent crashes have involved serviceable aircraft.
Weather conditions in Turkey are no better and no worse than most parts of the aviation world.
Turkish ATC is competent, and the airfields generally well-equipped.

Is it pure bad luck, or is there an issue to be solved to lessen the attrition rate?

Last edited by RoyHudd; 6th Feb 2020 at 17:40.
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Old 6th Feb 2020, 17:23
  #153 (permalink)  
 
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Originally Posted by DaveReidUK View Post
There's a rather extended and facile debate on this topic in the Comments section of the Avherald report on the accident. Last time I looked, nobody had provided any non-anecdotal evidence to support the proposition that the 737 is more prone to overrun than the A320.
As a person who is always interested in math and statistics, I've done some research on this question that was brought up repeatedly. Here are the comparison between the runway excursion rates of the B737NG vs. the A320 family. I'm not going to state any opinion, take these numbers and interpret as you wish:

Runway excursion hull losses in the past 2 years involving the B737NG (6700 built):
PGT8622: Jan 2018
CXA8667: Aug 2018
UTA579: Sep 2018
ANG73: Sep 2018
BSK293: May 2019
PGT2193: Feb 2020

Runway excursion hull losses in the past 2 years involving the A320 family (9200 built):
N/A

Since the discussion here is mainly around Pegasus Airlines and their training procedures, some have mentioned that if Pegasus had Airbus, they would also have runway excursions with that fleet too. I did some online research into their fleet type vs the accident rate of each type. Again, no opinion here, take the numbers as you wish.
Pegasus has 45 A320 family aircraft, 32 B737NG aircraft. (So about 60% A320, 40% B737). They've had 3 excursion incidents: Jan 2018 (737), Jan 2020 (737), and Feb 2020 (737).

These are some stats from a quick bit of research to answer this question that some of you brought up. Hopefully this helps. Condolences to the families and may the hurt have a speedy recovery.
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Old 6th Feb 2020, 17:30
  #154 (permalink)  
 
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NG 10 kts tailwind is standard, 15 kts is an option. You pay, you get it, and that is the way it has been since the NG was new.
I know, I have flown it since it came. End of that discussion.

The NG has not been prone to overruns, the -800 has. I donít think any of those incident/accident aircraft was put on the runway in the touchdown zone at the correct speed. All came in high, hot, not configured, tailwind, flooded runway, any combination of. This accident is just another example on how not to do it.
The -800 will bite you when you do donít fly it correctly.

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Old 6th Feb 2020, 17:43
  #155 (permalink)  
 
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Originally Posted by PJ2 View Post
Thank you, sleeper. Any word on the captain?
our newsoutlets only report on the copilot, nothing on the captain yet.
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Old 6th Feb 2020, 18:44
  #156 (permalink)  
 
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Originally Posted by sleeper View Post
our newsoutlets only report on the copilot, nothing on the captain yet.
This report on the pilots from a BBC article:

Transport Minister Mehmet Cahit Turhan said authorities had not yet been able to speak to the pilots, a Turkish national and a South Korean, who were believed to have been injured in the accident.
https://www.bbc.com/news/world-europe-51384667
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Old 6th Feb 2020, 18:48
  #157 (permalink)  
 
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Originally Posted by sleeper View Post
copilot, dutch, is in hospital.
authorities had not yet been able to speak to the pilots, a Turkish national and a South Korean
Does that imply there were three crew on the flight deck ?
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Old 6th Feb 2020, 19:06
  #158 (permalink)  
 
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Originally Posted by jmmoric View Post
There has to be some consideration... you can land with 15 kts reported wind, with gust up to 24 kts not reported.

And eventhough you get a mean wind of 15 kts reported, you will not be updated on the wind, unless the mean wind gets to 25 kts.... if you get the idea?
Negative, thatís not how it works.
The max gust is always used for tailwind and x-wind calculations. Maybe itís done differently at other airlines in different parts of the world?
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Old 6th Feb 2020, 19:08
  #159 (permalink)  
 
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Originally Posted by DaveReidUK View Post
Does that imply there were three crew on the flight deck ?

There are a lot of turkish immigrants from decades ago in holland. Their children are born and raised there and are dutch. Because of their ancestory they also receive a turkish passport at birth and turkey sees them as turks. They even have to go into military service unless a monetary fee is payed. I would not be surprised if the F/O is a dutch national with a dual turkish passport.

Last edited by sleeper; 6th Feb 2020 at 19:21.
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Old 6th Feb 2020, 20:15
  #160 (permalink)  
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Thank you sleeper, Airbubba. DaveReidUK, re 3rd crew member, hard to say with present info but it would be unusual, no?
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