Boeing 747 loses parts after take-off from Maastricht – 2 injuries | Hacker News Reader

Boeing 747 loses parts after take-off from Maastricht – 2 injuries

aviation24.be

106 pointsUncleOxidant40 comments

I can't find it now, but there was an NPR segment that ran about 3 days ago interviewing people in the airline industry.

Their general aggregate claim was that pilots and maintenance technicians have lost much of their normal routine due to the drastically reduced flying hours, and that this raises the risk of accidents.

Though the conclusion was that this is not something to be very worried about, it is uncomfortable to see two incidents like this on the same day.

"drastically reduced flying hours" - could anyone clue moi in on what this means/why?

Because of COVID demand for air travel has dropped rather dramatically. Lots of planes being mothballed, pilots not flying regularly etc.

There are less flights due to the pandemic.

https://www.statista.com/statistics/1104036/novel-coronaviru...

Not in freight though.

Covid. There have been significantly fewer flights than usual over the last year.

The argument is that pilots and ground crew are less busy, with bigger gaps between work, the result being that they are "rusty" for want of a better word, and so more prone to making mistakes/oversights. This seems plausible, but hard to know.

Not Covid. This was a freighter that was flying back and forth between Maastricht and New York. It did 3 flights on the day before. So it was in active service and being maintained normally.

https://www.flightradar24.com/data/aircraft/vq-bwt https://www.planespotters.net/airframe/boeing-747-400-vq-bwt...

> Not Covid.

even if so doesn't diminish the point in the argument. there are stories[0][1] that pilots have this problem (and are complaining about it) so it would be obvious that this holds also for all other staff.

apart from confusing the routine with changes that have not been tested / practiced there is also economic anxiety affecting them (perhaps even more than other industries). In any case the aviation industry usually keeps good tabs[2] on their employees mental health.

_____

[0] Grounded pilots out of practice because of COVID-19 spark airline safety fears https://www.japantimes.co.jp/news/2020/12/05/business/ground...

[1] FAA issues warning to airlines after a spike of in-flight incidents due to rusty pilots flying emptier planes than usual due to coronavirus https://www.businessinsider.com/pilot-safety-reports-show-ne...

[2] COVID-19 crisis and its effect on aviation mental health https://www.eurocockpit.be/news/covid-19-crisis-and-its-effe...

Freight planes are not serviced by dedicated freight mechanics. Passenger planes are well below capacity and maintenance companies are as well.

I think it would less because of lost routine, more because of less work / more bored / less concentrated. It's well known, for high quality on work, you should have enough work (not super stress, but no free time to think about to much other things).

A paragraph near the end of the article implies that this may have been a bird strike, or something "sucked into the engine".

So maintenance failure would have played no part, and the fact that 2 incidents happened on the same day is just that, "co-incidental".

I speculated 9 months ago this was going to happen, still consider it reasonable to think that any disruption to such tightly operated industry will ignite some butterfly effect here and there.

https://news.ycombinator.com/item?id=23016139

In terms of the effect of reduced flights from the pandemic, it should be noted that this was a freight aircraft (the vast majority of traffic from Maastricht Aachen Airport is freight, even pre-pandemic there were only a few seasonal/charter passenger flights).

Living under the flightpath, I haven't noticed a huge change in traffic. In fact, it seems that the airport handled more freight in 2020 than it did in 2019:

https://www.cbs.nl/en-gb/news/2020/31/air-travel-at-less-tha...

Probably because of freight that would normally be transported in the hold of passenger flights from Schiphol, Brussels or Dusseldorf.

A few points on this... I'm by no means an expert and two incidents in one day is by no means a correlation.

1. Some people here have pointed towards the Birthday paradox making this seem worse, with another flight suffering a somewhat similar issue on the same day. Sure, but with so few flights operating, I would expect this not to be such a great factor. The number of colliding Birthdays in a class should be greatly reduced with fewer students.

2. Another idea is that it could be that this happens all the time and we just don't realize. I imagine people living within flight paths being showered with engine parts on a regular basis would get more news attention.

3. I suspect many of these planes prior to the lockdown would rarely spend longer than 12 hours on the ground. I suspect now these planes could be spending weeks on the ground. I remember a picture showing tonnes of planes parked up on a runway waiting for operations to pick back up.

4. Regarding (3), that means these engines are possibly being thermal cycled unlike they've previously experienced. I imagine a jet engine remains hot internally for quite some hours even after flight - how regularly have they been reaching minus temperatures?

5. Regarding (3), with fewer flights these planes might be reaching their maintenance timeouts rather than air mile timeouts. It could be that the timeouts for maintenance are too long.

6. Regarding (3), due to reduced operations, airlines could be skimping out on maintenance - which I believe requires entirely disassembling the engines and checking them. This would of course only really go undetected if engine maintenance is done internally.

Just some thoughts anyway, would like to hear from some aviation experts.

This was not a passenger plane and it did several flights back and forth to new york in the 48 hours before: https://www.flightradar24.com/data/aircraft/vq-bwt

So, your are off on the wrong track as this seems unrelated to covid, reduced flying hours, etc. The plane was basically flying back and forth pretty much non stop.

It's an old plane, stuff breaks once in a while. I'm sure there will be an investigation and it will likely point to some overlooked defect, metal fatigue, or perhaps it hit a bird or something like that.

The thread for the other, similar incident out of Denver: https://news.ycombinator.com/item?id=26208555

We recently also had http://avherald.com/h?article=4e2fd449

Two different planes. Two different engines. Two different countries.

Same day.

The odds of this have to be as close to zero as anything I can think of.

Think witchcraft.

maybe related to a large number of planes sitting idle due to covid - come back in to service after sitting for 9 months and unexpected degradation has taken place

This is what I'd bet on. We have a ton of good information generated over many decades about the maintenance procedures that must be followed for commercial aircraft that are in daily use. We really haven't had a time in history when this many planes were parked for a significant period of time.

On first blush, isn't this an application of the Birthday Paradox? If stuff-falling-off-planes is a birthday event that happens at random, if it happens 23 times a year you'll get two happening on the same day every other year on average.

Eg if you pick a year (say, the 365 days ending today), if there were 23 stuff-falling-off events you'd have a 50% chance of two havjng happened on the same day.

If it happens 10 times a year, the chance they coincide is 12%, which means it will happen more than once every decade. It's only when you get down to 5 times a year that it gets really unlikely to overlap...

That said, uncontained engine failures do seem to be rare enough that two of them specifically coinciding really is very unlikely but in the realm of "weird coincidence" unlikely and not "supernatural" unlikely.

I also would suspect this sort of minor incident is much more common than most people realize.

When you have no passenger injuries these things don't usually make the news.

How many passengers are even aware of contained engine failures?

There can be a lot more failures than people think.

I'd guess most people are also bad at estimating how many car accidents there are in a year.

In the case of a contained engine failure, don’t planes immediately land at the closest safe location? Passengers would definitely know.

Usually, but that can be very far way. Look up ETOPS.

It depends.

The Denver one [0] basically landed straight away at the same airport 40 minutes later. The Maastricht one [1] circled around for an hour, and landed on a completely different airport. The whole "immediate" and "closest" is relative.

Strange as it may seem, an engine failure isn't that big of a deal: the aircraft is designed to fly for hours while missing an engine. However, the aircraft is now in a bit of an unknown state. The pilots need time to work through their checklists, determining what the exact impact is. The airplane might be leaking fuel; it might've lost a set of hydraulics; maybe it's on fire; maybe the engine can be restarted and everything is fine.

Landing as soon as possible at the closest safe location might turn out to be hours later and hundreds of miles away, perhaps even at your destination airport!

[0]: https://uk.flightaware.com/live/flight/UAL328/history/202102... [1]: https://uk.flightaware.com/live/flight/LGT5504/history/20210...

The point was often the plane would land somewhere that isn’t their destination, which would at least clue them into the fact that there was some significant mechanical issue.

> How many passengers are even aware of contained engine failures?

All of them. If they somehow miss the noise and vibration, they'll definitely notice the fire and/or smoke trailing out of the engine.

Compressor failures aren't minor events. If it happens during certain phases of flight the asymmetric thrust can create a severe challenge for the crew. More than one airliner has crashed as a result. Asymmetric thrust due to an autothrottle problem may be why Sriwijaya 182 (a 737) crashed last month.

Poisson Distribution theory.

https://news.ycombinator.com/item?id=26209286

According to local news[0], one of the injuries was an elderly lady who had to be treated for a head wound, whereas the other injury concerned a child which had developed burns after picking up the hot debris.

[0]: https://nos.nl/artikel/2369529-boeing-verliest-stukken-metaa...

Reminds me of this video: https://www.reddit.com/r/nonononoyes/comments/lop1kw/united_...

CNN story about it: https://www.cnn.com/2021/02/20/us/united-airlines-flight-ret...

Nostradamo here: there is a third party part that is the same in both planes and is at fault. That's the only posible explanation.

Boeing sure is on a roll lately

Boeing doesn’t make engines.

Supplier selection is an integral part of the manufacturing process. When you make and sell a plane, everything inside becomes your responsibility.

When my web app crashes, I don't get to say "No worries guys, the DB had an issue and we are not a DB provider so we can't be held responsible.

Pratt & Whitney engines have not historically been less reliable than GE or Rolls-Royce engines. If they were, no airline would use them.

And we don’t yet know whether that is the case now. With only a few engine manufacturers this could easily be a coincidence.

Engines are not Boeing’s responsibility. They are not even selected by Boeing, but by the customer airline.

But surely it's their sole responsibility to maintain and service the aircraft all the same?

Not at all.

Service is the airline's/owners respobility.

Perhaps it’s just that posting a Boeing incident on HN is a reliable way to get upvotes. Don’t forget that everything you read here has been filtered.

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