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777 fan-blade / cowling failure over Denver

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  • #31
    Originally posted by BoeingBobby View Post
    Just got these from a friend that works for United.
    3WE, I guess you can give up on that flowerbed dream.


    • #32
      Another case of engine failure:
      Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.


      • #33
        NIce job Gentlemen. Oh wait, I said that once already. See Evan, this is how a professional well trained group of pilots do their job.


        • #34
          Originally posted by BoeingBobby View Post

          NIce job Gentlemen. Oh wait, I said that once already. See Evan, this is how a professional well trained group of pilots do their job.
          Indeed. Where did I ever throw any shade on the pilots here? They did a commendable job, as you said, because they were well-trained on adhering to instant recall procedure and took their time to run checklists and did not instead resort to improvisation.

          Captain Joe, however, states that the fire handles release the extinguishing agent into the turbines. They release into the trans-cowl spaces outside the turbines. This might actually be a central issue in this event because AFAIK one of the fire agent zones is the transcowl space between the outer nacelle and what we see on fire in the videos. If the nacelle structure fails and is stripped away, this would make any fire suppression there ineffective, thus the importance of those structures to not fail during an FBO event. As the report for the 2018 incident pointed out, the PW4070 was FBO certified using different structures than the ones used in production. So maybe something needs to be strengthened there...


          • #35
            Looks uncontained to me


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            • #36
              Originally posted by xspeedy View Post
              That could easily be from a piece of the cowling. A T-wheel coming out the side will usually pepper the bottom of the fuselage and or wing.


              • #37
                Originally posted by BoeingBobby View Post

                That could easily be from a piece of the cowling.
                Exactly. Here is a better picture. There are several reasons why this doesn't look at all like an high energy shrapnel impact (from a blade being shot out) but rather a blunt-force impact (from a piece of cowling flying)

                Click image for larger version

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                --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
                --- Defend what you say with arguments, not by imposing your credentials ---


                • #38
                  The pilots and the air traffic control really performed to perfection. Amazing. Maybe Pratt & Whitney needs better processes, but this crew has performed in a way worthy of professionals.


                  • #39
                    Copy of the (now published) EAD for reference:



                    • #40
                      Just. Freaking. Brilliant.

                      Let's review...

                      1) A similar event occured in 2018. The investigation revealed that the fractured blade had been TAI inspected before being returned to service. Metal fatigue was detected. The inspector misinterpreted the metal fatigue however as paint issues. An AD was issued calling for TAI inspections with very generous compliance times. Now, after the recent repeat performance, an emergency AD has been issued with essentially the same requirements but with compliance before further flight.

                      2) The 2018 investigation revealed that the TAI inspection did reveal metal fatigue. The problem was that the TAI inspector attributed the marks of the scan to imperfections in the paint process that is performed prior to the TAI inspection. He made this error because he was not adequately trained on the TAI inspection process. He had about 40 hours of on the job training as opposed to the 40 hours of classroom training and then 1,200 and 1,600 hours of practical experience requirements for the commonly used eddy current and ultrasonic inspections.

                      3) The new AD references the 2018 P&W ASB that specifies procedures for performing thermal acoustic image (TAI) inspections of 1st-stage LPC blades.

                      So has nothing been learned? The problem in the first place wasn't that these blades were not getting inspected. It was that the inspectors did not know what to look for and how to interpret the results. That takes intensive training. Yet, this AD makes no mention of this. It apparently leaves the inspection process to 'owners and operators' rather than Pratt & Whitney.

                      Expect more fan blade off events I guess.