Originally posted by BoeingBobby
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777 fan-blade / cowling failure over Denver
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Another case of engine failure: https://youtu.be/7TJPmkcPer8Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.
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Originally posted by BoeingBobby View Posthttps://youtu.be/q5Wler87pwY
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.
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...
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Originally posted by xspeedy View Post
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Originally posted by BoeingBobby View Post
That could easily be from a piece of the cowling.
--- 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 ---
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Copy of the (now published) EAD for reference:
https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf/0/e4c5740884adbc78862586860008e6e8/$FILE/2021-05-51_Emergency.pdf
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Originally posted by flashcrash View PostCopy of the (now published) EAD for reference:
https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf/0/e4c5740884adbc78862586860008e6e8/$FILE/2021-05-51_Emergency.pdf
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.
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Originally posted by Nervous_Flyer View PostLooked like the plane got a nasty breach in the body. I wonder if that plane is now scrap.
Pressurized hull was not compromised, wing structure doesn't seem to be compromised either, I forecast that this plane will be flying again after spending tons of money in a deep inspection to confirm that the structure was not compromised, a new fairing, and a new engine and nacelle. And doing some minor "body work" on other dented parts that might have received the impact of pieces of cowling, like possibly the leading edge of the wing and vertical stabilizer.
Unless... United was already planning to retire this relatively oldish 777 in these times of COVID and low demand for flights, then this can be the perfect excuse to anticipate the decision.
But from an "extent of damage" point of view, this is most likely a minor situation, might not even qualify as an accident officially.
--- 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 ---
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Evidently same plane, same engine,same route, same failure in 2018. Two years, apparently nothing really fixed. Passengers, of course, would never know they were boarding a plane with an engine that had failed over the Pacific, preparing to land. Well, at least that time the junk might have ended in the Pacific, not on a playground.
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