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Since a brand new A350 has literally the exact same design specifications / G limits as an airliner built in the fifties does (A 1955 F27 Fellowship will break up at 2.5 G-3.75G, same as a modern Airbus jet - anymore than 2.5 G it will start to break up), and there were quite a few airliners from the 50's and 60's era losing wings or being destroyed completely as a result of turbulence.

Are there any Airbus planes that have broke up due to turbulence or accidents that were likely due to turbulence, but covered up?

Do Airbus planes have systems to avoid Clear Air Turbulence, and avoid flying over mountains, since most turbulence related inflight breakups occurred due to mountain wave activity? (BOAC Flight 911 for instance was flying over the top of a mountain - it experienced G forces of +9 and -4, and broke apart and crashed).

https://en.wikipedia.org/wiki/Wien_Consolidated_Airlines_Flight_55

https://en.wikipedia.org/wiki/BOAC_Flight_911

https://en.wikipedia.org/wiki/Braniff_Flight_250

https://ral.ucar.edu/aap/turbulence

(scroll down the last link for photos of the DC-8 jet with half its wing and engine torn off due to turbulence while flying at 31,000 feet over the Colorado mountains)

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    $\begingroup$ Why Airbus specifically? $\endgroup$ – zymhan Nov 12 '18 at 17:18
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    $\begingroup$ Your first sentence is just false. The certification specification have changed significantly in the fifties. $\endgroup$ – DeltaLima Nov 12 '18 at 17:43
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    $\begingroup$ Hello Willy A. Asking for which accidents are due to turbulence but covered up is asking for pure speculation / opinion. We don't do that here. Therefore I vote to close this question. $\endgroup$ – DeltaLima Nov 12 '18 at 17:50
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    $\begingroup$ @DeltaLima. How can you state a question is speculation, and vote to close it, and also submit an answer!! That is so hypocritical...!!? The question is NOT speculation, because it’s based on a false premise, as your answer demonstrates. $\endgroup$ – Penguin Nov 13 '18 at 11:26
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    $\begingroup$ "Are there any Airbus [...] accidents that were likely due to turbulence, but covered up?" I read that as "are there security agency reports that are based on falsification?" $\endgroup$ – mins Nov 13 '18 at 12:09
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The Aviation Safety database lists 91 accidents due to turbulence as of writing. None are on Airbus aircraft. The most recent in flight breakup of a transport aircraft listed was in 1993.

All of the aircraft in your examples are fairly old designs, dating back to the 60's or earlier. Your statement that the A350 has the exact same design requirements as an F-27 is inaccurate. While the load factors required for certification may have remained constant, the actual loads aircraft must be designed to survive have changed over time. As an example, for transport aircraft, the FAA regulation on gust and turbulence loads is 14 CFR 25.341, which has been updated 3 times since it was originally introduced in 1965. For the F-27 incident in Alaska, one of the factors noted was cracks in the wings from a lack of maintenance. Maintenance has been improved since then, as has the durability of aircraft designs. As accidents happen and the industry learns from experience, designs improve to better anticipate the conditions that aircraft will actually experience.

Other than the DC-8 in your last link, all of the occurrences happened in the 60's. Apart from the design of the aircraft, a lot has changed operationally since then. Weather radars have improved dramatically, both on the ground and on the aircraft. Modern radars have a much better ability to detect turbulence, even clear air turbulence to a degree. They have also become much less prone to operator error. Weather satellites now provide information on weather even in remote areas. Forecasts have improved as well, providing pilots and dispatchers a better idea of areas that should be avoided.

Below is an example of the kind of information that modern radar systems can provide to pilots about weather conditions in their path.

Weather Radar Thread Detection
Source

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    $\begingroup$ Thanks. I recently came across an incident report on a SouthWest 737 that encountered severe clear air turbulence. The FDR registered peak vertical accelerations of +3.52 G. Here's the report - aeroinside.com/item/3306/… The Design Ultimate Load of a 737-800 is around 3.7G. Does this mean that 737 came really close to breaking apart? I'm interested in an answer to this, thanks! $\endgroup$ – Willy A Nov 12 '18 at 19:00
  • $\begingroup$ @WillyA the report lists the aircraft damage as "none" and it actually appears to be on a flight right now, so I would guess it wouldn't have substantially exceeded limit. $\endgroup$ – fooot♦ Nov 12 '18 at 19:20
  • $\begingroup$ If you've seen the 777 wing testing video, you can see how things go from ''a little iffy'' to ''oops wing snapped off''. I've looked at various websites about modern commercial airplanes and it says Ultimate Load is 3.7G..Ultimate Load is where severe structural failure will occur, eg wings snapping off, horizontal tail snapping off, etc. $\endgroup$ – Willy A Nov 12 '18 at 19:27
  • $\begingroup$ Reading the BOAC 911 accident description I also noticed that “at an indicated airspeed of 320 to 370 knots”. That's rather fast for today's standards, and because the wings produce much more lift before stalling at higher speed it means turbulence caused significantly higher loads for them than if they were flying around 250–270 knots that would be typical climbing speed these days. $\endgroup$ – Jan Hudec Nov 12 '18 at 19:34
  • $\begingroup$ @WillyA everything above the limit load will cause permanent damage, and the video you referenced is testing to 150% of limit load, so there is a lot of room in there where the wing will not break but it has been damaged. $\endgroup$ – fooot♦ Nov 12 '18 at 20:11
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TLDR: As near as I can tell, probably none with the past few decades

I went to the NTSB's accident database https://www.ntsb.gov/_layouts/ntsb.aviation/index.aspx

This contains information since 1962. It does contain information from foreign sources, although I do not know if 100% of foreign accidents are reported here.

I searched for Make:Airbus, Damage:Destroyed, Injury Severity:Fatal, and keyword "turbulence" within the summary.

There was only one result, American Airlines flight 587 November 12, 2001. However, if you read the report, you'll see that the turbulence was not severe (0.3g versus the 2.5+ mentioned in the question). The summary text said

The National Transportation Safety Board determines the probable cause(s) of this accident to be: the in-flight separation of the vertical stabilizer as a result of the loads beyond ultimate design that were created by the first officer's unnecessary and excessive rudder pedal inputs.

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    $\begingroup$ There was no reason for the FO to be seesawing the rudder during that incident. In a swept wing jet you never touch the rudder pedals once you are airborne unless there is an engine failure or some other asymmetric drag event because if you make big rudder inputs you get dutch roll started. I would put my feet on the floor once we were above 1000 ft or so because if I left them on the pedals I would instinctively squeeze bits of rudder when applying aileron, and you're not supposed to. The yaw damper takes care of that stuff by itself. $\endgroup$ – John K Nov 12 '18 at 18:45
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Aircraft design specification have changed significantly since the fifties of the last century. Your claim that the:

a brand new A350 has literally the exact same design specifications / G limits as an airliner built in the fifties does

is just false.

See for yourself at the FAA website. For large aeroplanes, the applicable regulation is FAR 25.

Screenshot of FAR 25 changes showing change dates far beyond the 50's

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  • $\begingroup$ Then why do both the old 707 and the new (say, A350) have Design Ultimate Load @3.75G? Past Design Ultimate Load, then things like wings come ripping off at the roots. If modern aircraft were stronger in a way they could have survived the turbulence that tore the older era aircraft apart, wouldn't the Design Ultimate Load be something like 5 or 6G? Why is it the same as vintage aircraft? This is something I don't understand so I'd highly appreciate it if you could clear this up for me. $\endgroup$ – Willy A Nov 12 '18 at 17:50
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    $\begingroup$ That is an excellent question! I am happy to answer that if you ask it as a separate question. It might take a while, as I am about to leave for a trip, but I'll answer it eventually. $\endgroup$ – DeltaLima Nov 12 '18 at 17:53
  • $\begingroup$ Ah okay. I'd be very interested in an answer! $\endgroup$ – Willy A Nov 12 '18 at 17:53
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    $\begingroup$ @WillyA - that would actually make a much better question. Also, While DeltaLima is good (really good!) he's not the only one who can answer questions, so don't worry about the fact that he won't be around for a while. $\endgroup$ – FreeMan Nov 12 '18 at 18:20
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    $\begingroup$ @FreeMan thank you for those nice words. WillyA, FreeMan is right, there are many members around here who will be able to give you an answer better than I would be able to give, so please don't wait for me. $\endgroup$ – DeltaLima Nov 12 '18 at 21:16

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