The potential for Aircraft failure, fatigue, and structural failure is something that anyone in the aircraft industry is familiar with. Aircraft undergo rigorous testing before they can be considered safe and certified for flight to ensure that they can operate how they need to.

According to Boeing, equipment failure, which includes structural failures, only accounts for about 20% of accidents in today’s aircraft. We’ve come a long way from early flying machines, where nearly 80% of accidents were related to some kind of mechanical or structural failure.

Still, since safety is at stake, metal fatigue and failure is something that must be considered with every maintenance inspection. Let’s take a look at fatigue and metal failure.

According to the International Air Transport Association (IATA) data, there were only 53 accidents and 240 fatalities in the last year 2019. There were 4.54 billion people have traveled through planes and there were 46.8 million trips.

Aircraft failures

Old days, Aircrafts were made out of metals and there were more crashes were occurred. Among of various reasons, FATIGUE FAILURES were very important and dangerous factor. Because it won’t show any foreshadows.

Aircraft failures due to Fatigue

YearLocationFlight NameReason
1919ItalyCaproni Ca.48Vibrations of the wing and suddenly broke
1930EnglandJunker F.13Due to turbulences, plan tail was broken
1953MexicoDouglas DC-6Due to turbulence, main structure was failed
1954Mediterranean SeaBOAC Flight 781  Roof fail due to fatigue
1954Mediterranean SeaSouth African Airways Flight 201Due to fatigue decompression happened
1963USAB52 Stratofortress Broken vertical stabilizer
1964USANRB 57 Canberraboth wings were failed
1964USAB52 Stratofortress Broken vertical stabilizer and landed
1965USAHandley page hastingElevator became uncontrollable due to failure of two bolts
1966USABAC One Eleven 203AEDue to turbulences, Horizontal and vertical stabilizers were broken
1976ArgentinaHawker Siddeley 748Starboard wing was failed
1977ZambiaBoeing 707Broken right horizontal stabilizer
1978Norway  Sikorsky S-16Rotor blade was loosened from the knuckle joint due to fatigue
1985JapanBoeing 747 SRTail fin was blown out
1988USABoeing 737Roof top was blown off
1992NetherlandsBoeing 747One engine was ripped and one was broken. Crashed on landing
1997Norway  Euro copter AS 332L1 Super PumaDue to fatigue failure in the Spline, power transmission shaft was broken and crashed in to the sea
2002TaiwanBoeing 747-200Tail section was broken off and air craft was disintegrated in to several parts
2005USA  Grumman Turbo-Mallard G73TWings were broken in flight due to fatigue

The maximum load that can bear the metal is called tensile strength. But fatigue failure happens less than it. If there is Fluctuating force or cyclic loads fatigue failure can be initiated. With the increment of the force, the number of cycles needed to fail will reduce as follows. If the force is lower than the critical level, there won’t be initiate fatigue failures.

Fatigue cycle
Fatigue S-N Curve

Factors that trigger fatigue.

  1. Temperature (Inversely proportional)
  2. Magnitude (amplitude) of the applied force
  3. Number of cycles or frequency of the force fluctuating

Then how these failures identify be observing the broken parts. That’s called Failure analysis. There will be a smooth start, curved lines (Beach marks) with having gaps, and finally a rough surface. Using those beach marks, the force and the frequency that the sample faced can be calculated.

Actual images of the crack surface of the fatigue failures.

Fatigue Crack

Fatigue Failure  Aircraft Failure Analysis

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16 comments
  1. I will hope so so many new technology and old memories
    high appreciate
    Thanks
    Sarath kumara

    1. Thank You for your comment, Mr. Sarath,
      hope to improve our content more, stay connect with us
      Thank you very much

  2. Your presentation is a good attempt.I will suggest few additional points.These i feel if include it will elevate your presentation to a higher level. 1 At the onset it is better if you define what is fatigue failure 2 The graph should be connected to the body of text with short explantory notes. 3 If you can go deeper to the text,you can mention the chemical composition of past air craft bodies and your proposals .4 One para is duplicated.5 If you can avail US channels that is solely for air aircraft mechanic,you can access more text

    1. Thank You Siri Mama for your valuable suggestions, hope to improve our content more
      Thank you very much

  3. I really appreciate your efforts to define failure and the fatigue failure in aircraft and ships. That is very good. But I saw a few basic grammar failures in your sentences. E h:”the sentences in paragraph 4 should be, there were only 53…
    Next there were 4.54 million people who have travelled… etc. I wish you all the best in everything
    Jagath Perera
    Deputy principal
    Maliyadeva College Kurunegala
    Srilankan

  4. This is a very well done article, as I read from other comments once it is adjusted and revised it would be amazing. One thing that would be nice are more citations for the pictures at the end and showing what aircraft it is from. It would also be good to not end the article so abruptly as I felt that the article had ended without giving examples of the other two leading causes of fatigue failure (Temperature and Magnitude) if those two were explained in detail with studies backing them up as leading causes of fatigue failure, also with pictures as a result of the outcome of the damage caused from temperature and magnitude then the article would be improved upon.

  5. Great article, but you could provide citations because you were putting information without references. There were also some grammar issues, but other than that it was a great article.

  6. It’s really worthy article WHICH clarifies the very hard topics using simple explanations & images . Keep it up.
    All the very best wishes.

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