AAIB reports are freely available
I can thoroughly recommend them as in-flight entertainment.
Though you may find yourself doing a pre-flight inspection as you board.
If you have ever travelled on an aeroplane, the chances are you have experienced some form of turbulence. For those of us who fly infrequently, it can be alarming and unnerving, but rest assured that for the pilots and crew who experience turbulence every day, it is business as usual. You will normally receive a message to …
I remember hanging around in Schipol, waiting for a connecting flight. While I was sitting in one of the bars, there was a big-screen TV playing Discovery Channel for anyone who was interested. Yep - it was showing something like "Air Crash Investigation", "When Planes Plummet" or something like that, with some wonderfully graphic footage of aircraft ploughing into mountainsides.
I was watching a program on my tablet in Schipol last year waiting for the gate to open. I looked up and see a plane on fire with lots of people at the gates looking directly ahead probably as confused as I was.
Only realised after it was put out it was a training rig in full view of gates we were at.
The best thing is the reason for that test crash was to to see if a newly developed fuel designed with a high ignition point would work ad intended and not burst into flames if memory serves.
It didn't work.... Quite spectacularly too (I recall it had some sort of catalyst near the engine which kept pumping fuel before being atomised reaching a high enough flash point to make the lot go up in in flames.)
This whole fuel idea was shown on Tomorrows World. They started by demonstrating that kerosene is hard to ignite by turning a blow torch on a dish of the stuff. They then did the same with an atomised spray to show how easily it burnt then.
The invention was an additive that reacted to violent movement, eg a crash, by turning the kerosene form a liquid to a jelly. The idea being that “solid” kerosene wouldn’t burn. The catalyst near the engine would disable the gelling mechanism.
In the test, a remote control plane was supposed to crash land on a runway that contained 4 obstacles designed to rip the wings (fuel tanks) apart. The pilot made a small error on landing and one of these obstacles ripped through an engine causing a flash fire. The additive did its job and the flash fire quickly subsided even though the destroyed engine led to more fuel than expected being available to the fire. Unfortunately, the flash fire was enough to get some of the luggage smouldering and a few minutes later a secondary fire started that eventually burnt out the plane. The test was deemed a failure.
Here's a scenario posted earlier by Boris the Cockroach.
"The book for the plane said grease every 5000hrs (or whatever it was) , manglement put that back by another 1000 hrs to save money, grease monkey forgets to do it, inspector does'nt check its done, nor checks the nut for play."
Not an accident. A sequence of people not doing their jobs properly. Most days it would work out fine because although someone didn't do their job properly (which may be a design failure rather than a maintenance failure), someone else would have spotted it or some other system would have spotted it, and consequently no one would have been hurt. Sometimes it doesn't work out like that.
It's like that in lots of areas, not just flight safety. Construction workers are often supposed to wear hard hats. They don't actually need them, generally, unless something else has gone wrong. If that something else has gone wrong AND they're not wearing a hard hat, it's quite possibly hospital time (or worse).
Stay safe. You know it makes sense.
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Let's test it on the BBC today?
Could electric shocks curb spending? NO!
Could Thunderbird 2 become a reality? NO!
Are pancakes now Britain's favourite food? NO!
Could eating more fat boost health? NO!
Can Egypt's tourism recover from terrorism? NO!
Are 'killer' hornets on their way to the UK? NO!
Are 5 countries about to join the EU? NO!
Are we innovating at the slowest rate in a century? ... Yeah that one's self-evident to anyone who follows tech news.
For anyone who hasn't stumbled on it, Patrick Smith's 'Ask the Pilot' blog is well worth a follow. He's a trained pilot who knows his stuff - and I can also recommend his book of the same name as a present for anyone who is scared of flying:
Here's his take on turbulence:
Well of COURSE a Boeing 707 was brought down by turbulence. It's a Boeing! A 'Murkin plane.
The planes involved in 9/11, all Boeing. The plane that knobbled Concord ... that was a 'Murkin McDonnell Douglas. 'Murkin planes are flown continuously without maintenance until they fall apart mid-air.
A whole fleet of Boeing 737-300 were grounded when the roof panels literally started peeling off mid-flight, because nobody checked the rivets for fatigue for decades.
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If you want to experience turbulence I'd recommend a trip in a small one engine craft. Or even better a glider plane flying through a thermal.
I once had a girlfriend getting angry on me when we were flying together in a commercial airliner because she thought I was playing tough during "feeding time". My father was member of an aero club and took me along regularly that time, so I honestly felt nothing notable.
Good training for getting married, though...
Try a paraglider; probably the only aircraft in which the wing is not only flexible but liable to tie itself in knots in severe turbulence... though most of the time it will put itself back together for you, with a little help.
On the other hand, huge fun :)
a glider plane flying through a thermal
We don't fly *through* thermals, we fly *in* them. Feel the bump, wait a couple of seconds and then push the lifted wing down hard to start circling. Pull back to V(min sink). Keep an ear out on the vario and hope you found a good one.
> experience turbulence I'd recommend a trip in a small one engine craft
(Mine was a two-engine plane - a Twin Otter but the same principle applies)
Many years ago (1988) we flew from Plymouth to Jersey. On approaching the Jersey coast the pilot warned that we might want to hold on to our seats as it got 'a bit bumpy'.
Sure enough, coming over the Jersey coastline, we dropped what felt like about 50 feet. And then rose again, pretty quickly.
 And I just missed out on going in the co-pilot seat - pilot offered to let someone sit up front with him as long as we didn't touch the controls. I suspect he would get sacked nowadays if he did that..
In very light aircraft operating with only one pilot, the other front seat normally counts as a passenger seat. If it's used that way regularly it probably won't have dual controls, but often it will. Many times the control column can be removed fairly easily. Same goes for light helicopters.
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When the article includes gems like "the level of turbulence required to bend a wing spar is something even most pilots will not experience in a lifetime of travelling", and then even goes on to explain that wings are meant to flex, then you know that you're down at the level of an Open Day tour guide or a Sky News reporter, not a technical summary.
Nah, Harris College when I were a lad.
There were nowt wrong wit Polytechnics, except that they were under the control of local government not central government and they kept making central government look daft.
So they had to be removed from local government, and became universities.
> nowt wrong wit Polytechnics, except that they were under the control of local government
That was *everything* that was wrong with Polytechnics. I went to Leicester Poly in the mid-80's to do Information Technology. After a couple of weeks I asked to move courses over to Computer Science course as I hated the analogue electronics that we were forced to do. They refused.
The reason? The local council had mandated a one-way process (you joined the course, you couldn't transfer) because they were getting funding from Central Government for every student in the "IT Course" but not on computer science.
After failing the electronics section of the course I went back to re-do the first year but gave it up after a term. I'd been getting distinctions on the computer side of things..
Not that I'm bitter or anything.
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"Actually, I hadn't come across the Swiss Cheese thing until reading this article, and it looks like a useful thing for a number of applications."
Could have been summed up equally effectively in a single sentence, along the lines of "whenever an air crash happens it's almost never the result of a single failure* but rather an unfortunate coincidence of all involved safeguards failing at the same time"...
*yeah okay that crash involving the horizontal stabilizer actuator nut stripping out its threads due to inadequate greasing was pretty much a single point of failure.
quote "*yeah okay that crash involving the horizontal stabilizer actuator nut stripping out its threads due to inadequate greasing was pretty much a single point of failure."
But it was'nt
The book for the plane said grease every 5000hrs (or whatever it was) , manglement put that back by another 1000 hrs to save money, grease monkey forgets to do it, inspector does'nt check its done, nor checks the nut for play.
And I flew on one of those Frontier MD80's just after that accident..... Nice views of Mt St Helens/Mt Hood as we came into Portland though
Deflection of 5 metres on a wing nearly 30 metres long does not to my mind make 90 degrees.
Deflection of 10 metres full down to full up might be getting on for 90 degrees total flex, if for instance flexing outboard of engine only.
Wings are profiled - they thin towards the tip - think of it a bit like a kids drawing of a bird in flight.
I was flying across the atlantic in 1970 long before they had decent weather warnings and we hit a thunderstorm and free-fell 3000 feet before the wings seemed to do that. The plane smelt a bit funny after that. I was allowed on the flight deck a few hours later and the co-pilot was still shaking.
Several people shat themselves. I was 11 at the time and found the plane dropping out of the sky fun as I had flown before and felt safe but after we passed the storm the hostess who was looking after me (I was travelling alone) spent some time getting tissues and things for the poor buggers who lost it. Luckily the flight was only about 1/4 full as I think they ran out of loo paper.
Mr Leggett is correct. 90° is clearly an error.
It's an error traceable to BBC, as is rather-uncritically linked in this El Reg column.
BBC: "...that means the load bent the wing up almost 90 degrees."
Ref. BBC: http://www.bbc.com/future/story/20140319-stress-tests-for-safer-planes
Here's a Gizmodo page with a video of the well-publicized A350 Wing Test playing. It's clearly not bending up to almost 90°, not even at the tip. Maybe about 45-50°?, which is still impressively reassuring.
Ref. Gizmodo: http://sploid.gizmodo.com/heres-the-crazy-wing-bending-airbus-does-to-stress-test-1750425092
Also note that if you've got wings in a line and they then both go up 45 degrees, the angle between them is 90.
Especially on larger aircraft, it's always fun to point out the wings to kids before take off and tell them to look at the wings when flying. On the ground, the wings are hanging from the fuselage, in the air it's the other way round and the tips will be several feet higher as seen from inside the aircraft. A quick impromptu science lesson.
Speaking as someone who was once on a small aircraft approahing Sumburgh airport in the Shetlands in pretty turbulent weather - when we dropped from 4000 to 2000 feet in a matter of seconds, and the seat in front of me came off the rails and went over my head, complete with occupant - I think the case is demonstratable.
I find it a bit unnerving but not usually hugely so. But there was one time when it scared me. We were just leaving Manchester and entering the cloud layer. It felt like a significant drop and the engines that had been throttled back a little ramped back up again. Definitely a bit sphincter tightening for a moment :-/
But the worst turbulence was in the approach to Chicago back in '04. The flight out of San Jose had already been delayed because of storms in the area so I think we might have been amongst the first going in. That was up, down, left, right. Engines up, engines back for almost the entire approach. That didn't bother me as much presumably because I was expecting it.
"I think the worst I had was departing Wellington at night."
Rongotai is one of the worst airports to fly in or out of in the world.
A relative of mine was on ATC duty one say when an old Bristol freighter (Air Nelson) was flying out.
As he explained it, just as the plane reached the end of the runway (about 150 feet up) the wing "just kind of rippled". The pilot called the tower with a very squeaky voice "I think we'll turn around around and come back in" and flew _very_ slowly and gingerly around the circuit before _very_ carefully touching down with full crash team standing by.
Upon inspection it was discovered that a strong crosswind wind gust had "unzipped" most of the rivets along the wing and bent the spar. It was surprising that the aircraft hadn't simply fallen out of the sky and it left the airport in pieces on a flatbed.
Lest you think I'm joking: https://www.youtube.com/watch?v=IA7qkUeltNI is a good jumping off point for this airport. In the days before airbridges it wasn't uncommon for passengers disembarking from 737s to be blown around badly and injured on the air stairs.
He flew as a navigator in Lockheed Venturas over Africa. He experienced some real turbulence during that time, with the plane lurching or dropping like a brick suddenly as they were flying a much lighter plane than any Boeing or Airbus you care to mention through the weather, rather than over most of it.
Made me remember these kind of idiots. Those supposedly brave souls that start laughing at the first signs of turbulence and raise their hands as if they were on a roller coaster and having fun with the turbulence. They usually start joking about how the plane is shattering and try to impress their surroundings/girlfirends with anecdotes about that other flight they were long ago when things were much, much worse than now. That's usually a sign that they have not ever experienced how bad things can really get inside a plane. Because when things get really bad their hands go down, faces turn white and they stop talking and instead try to concentrate on not throwing up... which is what they usually end up doing.
That reminds me of an hovercraft crossing I once took. The sea was quite rough and when the craft got over a crest it seemd to fall down the other side. This went on for the full crossing. Much merryment to begin with and a lot of mess thereafter.
Is the passengers.
Specifically the ones who refuse to wear their seat belts when in those seats. They're the ones who suffer the worst injuries when things go pearshaped closely followed by those they collide with.
The rest of the passengers might get jerked around a bit but the belts stop them becoming projectiles.
Entirely agree. There are still unavoidable hazards even when you are strapped in, though - I did get to wear a large G&T on a flight from London to Copenhagen when the aircraft encountered unexpected turbulence, which was not a good look or smell shortly afterwards when standing in front of the passport checking booth. But pity the poor cabin attendant who spent 30 minutes clutching the bouncing drinks trolley while wedging it between the aisle seats.
"pity the poor cabin attendant who spent 30 minutes clutching the bouncing drinks trolley while wedging it between the aisle seats."
I've been on a number of flights where the pilots have announced that due to turbulence ahead cabin crew were to stow trolleys and return to their seats NOW.
Any airline which has pilots who let the trolley bounce for 30 minutes needs reporting to the FAA (or equivalent).
before you have chance to even take a sip Is a sure sign of turbulence.
Few years ago now (before 747-400) the 747s had to refuel in the Middle East when doing the Singapore and KL runs. I was on the way home from KL when just after the start of drinks service we hit some clear air turbulence. No warning, just suddenly my beer, still in its glass, was floating in front of my face. Negative G then zero G. Not a problem till we got back to positive G and everybody's drinks hit their tables. Had to feel sorry for the lady across the aisle with a white linen suite who had ordered port and lemon.
Always click my lap belt in place when seated now!
"No warning, just suddenly my beer, still in its glass, was floating in front of my face."
I've managed to catch mine on a couple of occasions when that's happened but usually missed it.
This and lost luggage are why you always put a change of clothes in your carry-on.
CAT events aren't very common these days as weather radar and inter-aircraft comms is much better than it used to be, but on the other hand turbulence is increasing overall.
Never been on a Rollercoaster. But when the airliner I'm in suddenly drops a couple of hundred feet I can't help but go "Wheeee!" One time turbulence was sufficiently prolonged that I figured we were all going to die so might as well enjoy it! That is the attitude I recommend. Figure there's sod all you can do about it. The worst part then becomes that when the fuselage disintegrates at 30,000 ft you're probably not going to get to enjoy the free fall (and if ever insult were to be added to injury!).
The last time it bothered me unduly was coming into Heathrow on a 757 into serious cross-winds. Barely above the runway we were swinging to maybe as much as 45° from the centreline. I could have kissed the pilot(s) for the decent landing they made of it - because at that point there isn't time to switch into whatever you'd call that mode I do at altitude.
I like to sit behind the wing and watch the spoilers, flaps and ailerons. I'm a control surface freak.
I was on one back to LHR from BRU that felt like it had its wheels on the ground the whole way. Bloody bumpy it was.
Most people on the plane looked in fear of their lives which, when the thing's bouncing around a few tens of feet while several thousand in the air, is just silly. The only real problem caused was that the dollies were sitting down rather than serving drinks.
Everyone relaxed and normal conversation resumed as we approached LHR. Just on the perimeter we hit wind shear and lost about 150 feet at once which, since that was a very significant amount of the margin between us and the solid stuff at the time, caused me some consternation although nobody else on board seemed to care.
Most passengers don't know what to be scared of.......
 The immediate application of "everything and the kitchen sink" in the engine department to get the thing to claw it's way to the runway by its fingernails led me to believe that the pilots weren't exactly happy either.
I was on one back to LHR from BRU that felt like it had its wheels on the ground the whole way. Bloody bumpy it was.
The most worrying turbulence I've ever had was early on in my flight training.
It was a perfect flying day - plenty of visibility, little wind. I was flying a 360° level turn. As I turned back onto my original heading, there was a pronounced bump - I thought I'd hit something.
I had hit something - my own wake. And it was lumpier than I was expecting...
The advice I was given a long time ago is to keep an eye on the cabin crew. You might feel like you're riding on the Nemesis at Alton Towers, but they really know how bad it can get. If they look calm, then you have nothing to worry about. If they're starting to look a bit twitchy, then for you to start crying like a little girl is an acceptable course of action.
I've been on a few flights with similar experiences (drinks down suits, etc.) but on one of the calmer flights I flew there was a little period of bumpiness where the crew were looking absolutely fine, as were (most of) the passengers. However, about 5 minutes after the bumps the lady looking after my section suddenly looked a little drained and took a break on the jump seat in front of me (exit row, first through US immigration...). She confessed to me quietly that she hates and fears turbulence, but hides it as best she can due to reflected fear...
Lesson to learn: The crew are humans with the same insecurities and fears as the rest of us. Sure, they face it more often but that doesn't necessarily make it any easier on them.
Since then I've not looked at them. Since quite a lot of turbulence that some would find uncomfortable is no worse than shutting your eyes as a passenger in a car going over bumpy road, I now just shut my eyes and imagine just that...
Has anyone else noticed how some airlines switch on the seatbelt signs at so much as a tremble, but others let you go to the loo when the plane's bouncing around like a 5 year old on meth?
Air New Zealand being a notable case in point. If you're flying with them, a top tip is to arrive with a catheter in place.
That's not my point. I've noticed that it's consistent. Some airlines put the belt signa on for a respectable fraction of the flight, always. And it's always even when there's no turbulence. Other airlines flying the same route are much more reasonable about it. I fly enough that I think I've got a reasonable claim to having observed a pattern.
It is a really good idea to keep your seat belt on at all times, warning light on or not, unless you have to get out of your seat. (By all means remove it after takeoff, slacken it a bit for comfort, and put it back on).
There are cases of passengers dying because of turbulence. The plane goes down hard, your head hits the luggage bins after "falling" upwards, your neck breaks.
I've been on a flight when the first warning of turbulence was my drink taking off. I wasn't scared after recovering from the surprise, but was most glad of the seat belt. I know enough (see above) to file that as "moderate". I've never encountered "severe" and don't want to.
The only turbulence that bothers me is the aftermath of a late night curry as many years ago I worked on light aircraft airframes for three years. My cheif engineer liked airobatics in anything so test flights were always 'fun'.
The most worrying thing to bother me was on a flight into Minnesota on the way to SF in 2000, ,it was January and outside on approach I could see pom pom sized snowflakes, as I looked down at the runway a few hundred feet below I could see a few cars parked under the runway lights in the snow. Then I realised that I was looking at a shopping mall parking area, at the same time as I was getting nervous enough to start running for the exit, the pilots must have realised the same thing, they powered up and even turned the taps on full in the kitchen sink. We circled and came back on approach about 3 miles down range and found the runway this time. That was Northworsten Airlines, I came back on American.
Although mine is a minimal one about flying around thunderstorms at the Grand Canyon while the Aussie in back emptied themselves into a bag, this one is someone else's - never verified.
I was just talking about a famous plane plummet caused by volcanic ash in Indonesia a long time before and describing the panic that must have been felt by the passengers because the pilots kept trying to restart the engines, 4 on that plane I think.
I reached the punchline about how a single engine was restarted just in time at 2000 ft and Barry, listening intently to my amazing story, said "I was on that flight".
Obviously, we all laughed but he continued to explain the route, the reason he was there and the fact that it was true, despite him being from Liverpool.
He also said it was the single most terrifying thing that had ever happened to him (duh!) and that was why he drank like a fish both before and during and after all his flights, of which he still had many, being in the international sales game.
At that time, there was no real way to identify the truth but he was adamant and never reneged in the years I knew him. I should make some enquiries these days using the resources we never had then.
But when i did, it was props, turbo-props, and jets. I had a simple set of steps that managed to get me through all the flights...
Find my seat
Fasten lap belt snug and low across hips
Stay in seat until end of flight
Remove belt when we arrive at our gate
wait for everyone to GTFO
thank the crew no matter what.
The worst flight I've ever been on was from Kathmandu to Pokhara in Nepal in a small twin-prop passenger plane in a thunder storm, the kind where you can see lightning striking the ground outside the wing. Theoretically, it was only a short flight, about 25 minutes (we wound up being unable to land due to the weather conditions and had to fly back to Kathmandu), but the whole way we were being flung about like a cocktail shaker in a show bar. I'm not a big fan of small aircraft, so I was not well pleased. However, on the plane with me were a trio Gurkha soldiers just returning from a tour in Afghanistan. Two of them, like everyone else on the plane, were completely still and silent. The third was feeling very talkative, and he said that flight was the scariest experience he'd ever had. Suddenly, I didn't feel so bad about being terrified; I figure anything that can scare a Gurkha just back from deployment is genuine cause for concern.
Back in my military days, the 707 was the plane for travel in the US. The wings flexed a lot. Was on a flight and the grandma type next the window expressed concern that the wings were "flapping". I told her my uncle helped design this plane. He was a helluva designer but couldnt't draw too well and anyway, the wings are designed to do that. By flapping we get to go another 50 miles an hour faster... She kept the puzzled look on her face until we landed but didn't bring up the wings flapping.
Beer, the drink for flying... ------------------>
Britten Norman Islander if I recall correctly. Short flight from Trincomalee to Colombo. They get two monsoons in Sri Lanka, one East coast, one West coast. When the West coast one is happening the giant black clouds roll in regular as clock work in the afternoon, huge lightning bolts, drenching rain, you get the idea. Now, sudden turbulence is certainly scary, but looking out the window as you fly directly towards a monsoon storm with no possibility to go around it; that's pretty scary.
Flying in and (4 hours later) out of Beijing, the 777 was twisting in the wind sheer; looking along the cabin from near the back, you could see the whole body pivoting +/- 15 degrees around the upper edge of the main frame, with the overhead compartments seeming to stay still and emphasis the twist.
Not sure if this was entirely a weather issue, as the previous flight in and out on a 747 was as smooth as silk
Our China Southern 777 also had dodgy brakes; on landing it would veer violently to the right every time the brakes were applied; even the stewardess liked scared (she was sat facing me); I was on board for three legs, Nanning - Guangzhou, Guangzhou - Beijing, Beijing - Shipol, and she had a death grip on her harness every time.
Well not in the same flight. During my PPL training on a humid summers day I felt quite a bump, and my instructor told me to look at the altimeter - it had just dropped 500ft! A few months later my friends and I were flying back from Australia and the plane was attempting to land at Bankok during a thunderstorm. After holding for 20 minutes, they decided to give it a go. During the decent there were several big bumps like the one I experienced. I reassured my fiends everything was OK, but I was wondering how many 500fts we could have left.
"The flexing and bending of a wing in flight is intended by design, and a very rigid wing would break much more easily. Skyscrapers are also designed this way, to actually sway a little – it makes them far more robust."
They could make the wing more rigid, but it would weigh more, reducing payload, range, and efficiency. They don't actually care how much it bends as long as it doesn't break.
For civil engineers, it is cost vs bending, though the deflection limits are normally set by Building Standards/Codes.
I am a professional structural engineer and it is a pity that what I understand to be an often repeated myth has been repeated here again. Perhaps another structural engineer will correct me if I am wrong but wings would not be weaker if they were less flexible. The idea that something has to be resilient or flexible otherwise it would break is true for a link between much stronger items that cannot be restrained (like flexible sealant between slabs of concrete) but it is not true of a wing or a skyscraper. A skyscraper may be tall and slender to look impressive. A wing is long and slender for aerodynamic reasons. In both cases these are constraints that make them more difficult for the structural engineer to ensure that they are adequately strong.
Reminds me of the time I was interviewing a structural engineer for my self build, and trying to impress me with his knowledge, he said that my 1860 stone staircase was 'cantilevered' and the iron and wood balustrade takes most of the load. Suffice to say he didn't get hired.
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