Announcement

Collapse
No announcement yet.

User Profile

Collapse

Profile Sidebar

Collapse
Evan
Evan
Senior Member
Last Activity: Today, 21:04
Joined: 2008-01-19
Location:
  •  
  • Filter
  • Time
  • Show
  • Source
Clear All
new posts

  • 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...
    See more | Go to post

    Leave a comment:


  • 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......
    See more | Go to post

    Leave a comment:


  • 3WE, I guess you can give up on that flowerbed dream....
    See more | Go to post

    Leave a comment:


  • Best I can tell, only the -112 designed for the 777 uses hollow-core fan blades that require the TAI inspection process. (The 1000G also uses the TAI inspection process. The GP7200 used on the A380 also uses hollow blades but they are all too new to require the TAI process). Still looking into this...

    But this is looking bad for P&W:



    and...

    Now, we are not talking about training hundreds of personnel here. P&W had only THREE inspectors to train for these blades, and one of them was a backup.

    The one involved in the 2018 failure was the second shift inspector. He was VERY experienced and qualified on many processes (he even worked on the space shuttle main engines). But he wasn't properly familiarized with the new TAI process.

    The issue was paint. Before the TAI inspection, the blades must be painted. The paint is then removed following the inspection.



    There was pressure. At...
    See more | Go to post

    Leave a comment:


  • This from the Seattle Times:



    The good news is that prior to both of the previous 777 blade failure incidents, the metal fatigue was detected by the inspectors. The problem was that, lacking proper training in the thermal acoustic imaging process, they both attributed these to paint defects and returned the blades to service. Therefore, inspections by properly trained personnel can quickly get these planes safely back in the air. But then then the FAA must require that the inspectors are properly trained in the future.

    The other issue, the CRFP bulkhead and cowling issues, are another story.

    And what about that Longtail 747...?...
    See more | Go to post

    Leave a comment:


  • The two issues that I believe are at fault are the inspection process for the hollow core titanium blades used on the PW4000 and weaknesses in the CRFP rear bulkhead and engine cowling structures. Inspectors may not be properly trained on the thermal acoustic imaging technology developed to inspect the new blade design. The engine was also fan blade out certified using an aluminum rear bulkhead instead of the CRFP one used in production.



    So why would they certify the thing using different materials than the ones to be used in production?



    So dumb bureaucracy strikes again. Is this a 777-specific issue?



    These appear to be 777-specific issues. The large -112 variant fan section of the PW4000 is only used on the 777. So maybe....

    But the blade inspection issue can't be specific to the 777. It wouldn't surprise me to learn that this issue was also behind the recent Longtail 747 PW-4056 incident....
    See more | Go to post

    Leave a comment:


  • P&W is another story. This was not the first PW4000 to suffer a fan blade / cowling failure, nor was it the first one to do so when bound for Hawaii. The lessons learned from the prior incident pointed to a training failing on the part of P&W regarding their TAI inspection process.



    There was also an AD involved:



    So it will be interesting to see about compliance on this a/c.

    https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf/0/bb315c3fce9e8c75862583a2005079f0/$FILE/2019-03-01.pdf...
    See more | Go to post

    Leave a comment:


  • Stupid but interesting question. The 777 was the last of the old-school Boeings, before Boeing was left in the hands of a cynical capitalist leadership focused blindly on short-term shareholder value. How many 777 incidents have occurred as the result of deficiencies in the airframe or avionics? The 777 was Boeing at its best. So when you want to goad me over my disgust regarding what Boeing has become, keep in mind that aircraft like the 777 are what I came to expect from Boeing....
    See more | Go to post

    Leave a comment:


  • I’m not having a blast. Unless that was just a pun....
    See more | Go to post

    Leave a comment:


  • Fixed....
    See more | Go to post

    Leave a comment:


  • These cowling-shedding incidents seem to be the result of inlet damage caused by departing fan blades and the resulting aerodynamic forces on the remaining structures. I imagine this was initially a fan separation, not uncontained core failure. However, parts were ingested and it is possible that this caused internal damage that might have breached the engine core. But the fire seems to be coming from something other than fuel, perhaps hydraulic fluid from damage to the external accessories.

    The issue I see in need of consideration is the ineffectiveness of fire suppression when the cowling disintegrates. Perhaps these structures need more robust requirements. What if this happened over the Pacific hours away from a diversion airport? Could that fire become dangerous? I think, probably not but it needs to be considered....
    See more | Go to post

    Leave a comment:


  • Cheap crackerbox, eh? At least those CFRP structures don't seem to do as much damage when they fall out of the sky. I guess one thing we learn here is that the fire suppression doesn't work very well without the cowling. Funny thing that the pax cheered upon touching down with a now-upward burning fire under a fuel-laden, possibly punctured wing. I'd be halfway out the door. No mention of whether slides were deployed...
    See more | Go to post

    Leave a comment:


  • Indeed. It never is. That's my point.



    But flight control computers make aviation much safer in general. The trade-off in risk vs reduction of risk is a no-brainer. There is no safety trade-off in moving away from plug-type cargo doors. It is simply less safe by its very nature. Nevertheless, research the story of how many hoops and levels of assurance Airbus was required to provide before gaining certification for FBW. It's inspiring. I'm convinced there will never be a crash resulting from a failure of flight control on these aircraft because the process was so cautiously considered and the system so overbuilt.

    MCAS was a different story. A crime really....
    See more | Go to post

    Leave a comment:


  • Best I can tell thus far, the B707, DC-8, DC-9/MD-80 and 737-100/200 had all plug-type cargo doors (all doors). The first time I see outward-opening cargo doors is on the 727....
    See more | Go to post

    Leave a comment:


  • Thirteen including you....
    See more | Go to post

    Leave a comment:


  • I agree, of course. But that's not how reality works. The designs for the 707, DC-9, DC-10, 747, 757 and whatever others aircraft have been affected were not known by the FAA or the flying public to be unsafe until after the weaknesses revealed themselves. So, the same could be true of the 777, 787, A350 et al. You are correct that the designs were not safe, but you wouldn't have known that when climbing aboard a 747 in 1985. I agree that certain aircraft such as the A320 appear to have safe door systems. given the years in service. But then, the B747 had been in service for two decades when the door on United Flt 811 failed in flight. As I said before, I hope that the lessons were learned and the weaknesses eliminated and redundancies added over the past three decades.

    But then here we are: it's still happening! Not baggage doors, thank the gods, but large cargo doors. If the problems were worked out, how is that possible?

    Again, inspiring this argument was my...
    See more | Go to post

    Leave a comment:


  • Yes, captain. You can't blame people for calling it the -800 though after the -100, -200, -300 and -400. 747-8 looks like a typo....
    See more | Go to post

    Leave a comment:


  • Not my favorite aspect of the NG's but look, emergency exits are so rarely used that the risk of the lock mechanisms failing is insignificant. I concede that the benefit of not having to stow the door in the cabin during an emergency probably outweighs the added risk of it not being a plug. If these were getting opened and shut between every cycle I would feel differently.

    One potential concern is that these doors are locked by an electronic system that requires power to remain in the locked position. What happens if the system loses power for some reason? There is still the lever position, which hopefully engages a second, mechanical lock, but that would leave the door one passenger lever pull away from opening in flight. This provides some detail:

    http://jdasolutions.aero/blog/firefi...ll-wing-exits/...
    See more | Go to post

    Leave a comment:


  • By the way:

    ...
    See more | Go to post

    Leave a comment:


  • One you didn't point out: the outward-opening upper deck emergency exit on the 747-400/800. I only once flew up there. That thing made me a bit uncomfortable. But then the pre-departure complimentary drinks fixed that. I assume it rarely gets used, so it will probably never fail in flight....
    See more | Go to post

    Leave a comment:

No activity results to display
Show More
Working...
X