[OT] Comet airliner - highly technical analysis of the cause of the crashes

[Spike]

It's a Powerpoint-style presentation of a quite long and deeply technical analysis of the structural failure, based on a very detailed search for the point of failure, which was found in recovered wreckage, and subsequent materials characterisation.

Most impressive is the calculation, based on modern understanding of the materials aspects and methods of characterisation, that suggests structural failure would occur after on G-ALYP after 1290 pressure cycles. it crashed after 1272 pressure cycles.

[AnthonyL]

I seem to recall that a contributory factor in the speed of sinking of the Titanic was due to rectangular corners.

I wonder if aeronatical engineers and naval architects ever talk to each other.

[Steve Walker]

Perhaps as impressive, the author, pilot and aeronautical engineer, Nevil Shute, wrote No Highway about an aircraft design failing due to metal fatigue. It was published 6 years before the Comet crashes! There was clearly some knowledge of it at the time.

[Bob Eager]

I was going to mention that. Excellent book. The failure was after about

1500 (it varied, part of the plot) flying hours.

Obligatory mention of this book, with loads of detail:

[The Natural Philosopher]

It became known really at the start of pressurised cabins. introduced in WW2 . But it wasn't well modelled.

[Tim Streater]

rectangular corners of what?

Titanic wasn't a naval ship. And I don't suppose aeronautical engineers, as such, existed in 1920 or whenever the Titanic was designed.

[charles]

In article [e-mail]>,

[Snip]

It sank in 1912, so was presumably built well before 1920

[Bob Eager]

Windows.

[Tim Streater]

Huh, meant 1910, intended to type 1910, typed 1920. Sorry about that.

[Tim Streater]

Surely once the windows were going under it was already a bit late.

[Harry Bloomfield, Esq.]

Tim Streater has brought this to us :

The Titanics windows were the usual round portholes, but they were left open, which didn't help to delay it going down.

[Bob Eager]

I was referring to more general instances (e.g. the Comet), not the Titanic. Sorry.

[John Brown]

AnthonyL [e-mail] wrote

Nope.

The ones that did the flying boats did.

[Brian Gaff (Sofa]

I thought everyone knew it was those square windows. Sadly I'm not going to download any powerpoint as it will be inaccessible. Brian

[Brian Gaff (Sofa]

Well not really as we all know one of the most common things in reports say lessons will be learned, but often they never are. I think in the Case of the Titanic that the watertight doors were simply not closed soon enough to save it. It was quite tall above the water line too and capsizing was always going to be an issue if they were not careful, Add to that that the old fashioned boilers were going to blow up when hit by cold water. The real stupidity was the lack of lifeboats for everyone and it seems a lack of proper evacuation plans as well. Brian

[Brian Gaff (Sofa]

There have been a number of events that were predictable though. The DC10 cargo doors, both Shuttle crashes were due to materials doing what they were not supposed to and a design flaw in the original design which used aluminium in parts that may get overheated if the carbon carbon laminate delaminated on re entry, Ally will burn as we know from the Falklands war.

Then there is the latest case of those modified Boeing 737 max planes where they crammed in larger engines and messed up the performance completely.

Even the 747 had early issues with engines made by Pratt and Witney flaming out, but at least they had four!

There also needs to be, in my view, an ai controlled beacon ejection system on commercial aviation because even with the sophisticated gps and data transfer to satellites, they still cannot find that Malaysian Airliner that went off somewhere and ran out of fuel over the sea.

Unfortunately accidents will always happen. Look at Concorde. That was a number of problems that occurred at once and some really bad luck. The latter will always be a problem, nothing is infallible after all. Brian

[Caecilius]

I'd heard (can't remember the source) that not having enough lifeboats to take everyone was actually commonplace at the time because lifeboats were intended to ferry passengers to safety and then return to pick up more people. The concept of evacuating in the open sea was, apparently, not something that was considered.

Not sure if this is true though.

[Andrew]

It was the rivets that failed when the ship sideswiped the 'berg.

They chose to use rivets that were a compromise of strength and cost from what I remember from the TV progs that were aired in 2012.

[Tim+]

Chose? We?re there other options back then?

Tim

[Steve Walker]

Possibly.

It has also been stated that the Titanic's davits were capable of lowering a lifeboat and swinging back to swing out a second one, but that for aesthetic reasons they chose to only have one row of lifeboats and not two.