another question about jet planes

[mattbiernat]

didn't want to hijack the other topic so i started my own.
on the way from Chicago to Dublin I've experianced some pretty bad turbulence. i mean people were puking on the plane (they served the dinner right before it started to shake). the plane was shaking and droping violently up and down. needless to say this trip made me hate flying.
anybody knows whether winds like these can bring down a commerical jet liner? this trip seriously scared the heck out of me.

[Harryc]

It's unlikely, but it has happenned. Google 'wind sheer crash'. This type of crash is usually closer to the ground than you'd be when you're having dinner on the flight to Dublin though. Odds wise, I bet mechanical failure is more likely.

[Brad]

Flying is fairly safe. I am no aerospace engineer by any means. My thought on flying is what some pilots say. Flying will never be safe until you eliminate the drive to the airport. I think of this when hitting a bumpy patch.

Never been on a ride like you were on though. Maybe I would change my mind.

Keep the shiney side up!

Brad

[andyP]

On a flight from London to Sydney during the last leg from Singapore, the plane hit a "wind pocket" just as I came out of the toilet. This resulted in me having to walk part of the way back to my seat along the cabin roof, (with all the coffee cups etc.). The resulting coming back to earth aka the cabin floor was needless to say interesting. Being at that time involved in skydiving I was dissapointed when the cabin crew refused to ask the pilot to circle and repeat the "ride".

Seriously there have been people injured in this sort of turbulence, that's why they recommend remaining seated with the belt fastened.

[joester]

In 1978, I was on my way from NYC to Germany on a 747.
We hit one of those wind pockets... and lost about 2000 feet according to the pilot who said with pride over the intercom that it was the biggest he had experienced in his life. I had just taken my seat after returning from the same stopping point as andyP.

You are right andyP. The ride is one Disney could never duplicate.

This was my first flight ever, and I thought it was fun. I boarded the plane knowing being scared would do no good, and wanted the best ride I could get. I got it.

Joe

[al7kz]

You didn't mention the model of airplane, but from my experience as an engineer for Boeing (stress analysis/wing loads/design-747) I can assure you that whatever plane you are in is designed and built to handle whatever you may encounter and then some. The updrafts and downdrafts are no problem for the plane, it is the sudden strong gusts that set the design condition. Watch the wing tip - how much it travels up and down in a gust is an indication of the gust loading.

Harryc is correct about wind shear. That's a special case near the ground and I believe most large airports have monitoring equipment for that - I know that Juneau AP does. Cheers & safe flying...

[rkawakami]

Sound like what the plane encountered is CAT (Clear Air Turbulence).

ref: http://www.fearless-flight.com/flight-s ... ence-facts

[jamerslong]

yea, turbulence sucks, the problem is that it disrupts the air flow around the Wings, the wind that is. usually not very dangerous just disturbing. because once out of the "air pocket" they can regain control and keep going, as far as mechanical Problems, i personally haven't had to make repairs to a jet from turbulence. there are some jet engines that will "stall" from loss of compression by crosswinds, all that happens is a loud bang that sounds like the engine exploded but this normally only happens on the ground, and these engines are being phased out and replaced with ones that don't stall by using a different compression method. but if they do stall then that engine is toast.

airplanes are safe, we have had aircraft loose all systems and still land and fly safely. systems include com, radar, Hydraulics, and GPS.

i could always scare you with interesting facts. about how the plane is held together. like the fact that the Wings are held on by one bolt and the engine is held on by two.
the skin of the aircraft is thin, your basically sent flying in a tin can.
but don't worry the pins on the engine are able to withstand 198,000 Psi an engine puts out 32,000-48,000 psi thrust, the pin that holds the wing on is about 8" wide and as long as the wing.
and the skin is held on by an incredible support structure.

as far as in the article about turbulence, they say wings are flexible. I can attest to that because i like walking to the wing tip and rocking the wing, the engine struts are just as flexible.

[mattbiernat]

thank you for clarifying this to me. I will try to relax more on the next flight. Instead of sitting in my steat and praying to God not to bring down the plane

[rkawakami]

<snip>... your basically sent flying in a tin can. <snip>

Well, now if that didn't already reinforce people's fear of flying, then nothing will!

[andyP]

<snip>... your basically sent flying in a tin can. <snip>

Well, now if that didn't already reinforce people's fear of flying, then nothing will!

And, AFAIK, the Lunar Landers from the Apollo missions were even flimsier

[joester]

My understanding of the lunar landers was that some of the walls were only 3 mils thick.


WHOA.

[jamerslong]

well lunar landers were extremely thin and composed mainly of mylar and an aluminum compound. i know the return pods are extremely resilliant and made compleatley different though.

Mylar is 98% reflective so it is also a great inulator and is virtually weightless and thiner then a sheet of paper (emergency blanket in the camping section), the Aluminum compund was kinda just to create a solid seal i would assume.

i remember a video of the new passenger plane to come out , the air bus 380 i think it is They Flexed the wings to 48 degress in a stress test before they snapped. amazing thing to watch, i think i saw it on engadget.

[draco2527]

didn't want to hijack the other topic so i started my own.
on the way from Chicago to Dublin I've experianced some pretty bad turbulence. i mean people were puking on the plane (they served the dinner right before it started to shake). the plane was shaking and droping violently up and down. needless to say this trip made me hate flying.
anybody knows whether winds like these can bring down a commerical jet liner? this trip seriously scared the heck out of me.

I had the same experience, however mine was an international flight...

The plane turned into a BIRD! I was seated on the "wing windows" and I SWEAR the wings were moving so far UP AND DOWN that you would think that the darn thing was a bird...after this I lost my love of flying...there have been other incidents but I think this one topped them all...

My sister was on a flight that she found "disturbing" for other reasons...(before 9/11)

She was coming over to visit and her flight was about 5 hours, as soon as the plane started moving she realized that the "guy" sitting next to her was "NOT ALL THERE"...every time there was a noise or anything that made the plane act "funny" he would mumble something...it got so bad that my sister started paying a little more attention on what he was "saying" in particular once he started turning into a water dispenser (he was sweating profusely)...she realized he was saying "what was that?"…

Well, as it turned out the guy had not flown in over 3 and this was his first flight after the “incident”…

He had been on a plane that had to do an emergency landing-from what the guy said it was more a death march then a landing, he happened to be sitting on the “wing” portion of the plane and noticed how one of the engines caught fire…and it all went downhill from there for him...

[Paul Unger]

There's footage of the Boeing 777 that flexes the wing to 154% of design limits before it snaps. Worth a watch to calm your fears.

[rkawakami]

[tongue-in-cheek mode on]
Yeah, but that's not a completely assembled wing with fuel tanks and engines mounted on it . And it's only being stressed (slowly) in a single direction, not like what I've seen outside a window of a 747 (have never flown in a 777) which was flapping like draco2527 mentioned. And that's not after going through several thousand LTO (landing/takeoff) cycles; can you say "metal fatigue" - remember the Aloha 737 from many years back?. This all from a test engineer and a one-time employee of NASA.
[tongue-in-cheek mode off]

In all seriousness, I'm sure that all airframes are suitably over-engineered. But I'm not an aeronautical engineer .

[jamerslong]

yes planes can be scarry, but they are extrealy reliable, for every system on the jet there is a back up of a back up of a back up. for instance, our jets have 4 engines, there are 3 power generators powered by the engines rotation, if the jet lost power there would be little hope, but there are 3 generators and it needs only one. most backups require only a flick of a switch. this is why you see so meany freaking switches on an airplane. we had an airplane that lost most of the outer panels due to severe rusting, it failed the inspections so bad that they decided to send the plane to DEPOT to have it rebuilt. We duct tapped the panels on because the screw holes were rotted out, the landing gears had broken retiaining rings and had to fly with the gear down and external locks applied. but it flew fine.

[bill bolton]

Worth a watch to calm your fears.

Just watching even a few episodes of "Air Crash Investigation" (aka "Air", "Air Emergency" and "Mayday" in various TV markets) will show why all the over-engineering in the world won't stop simple human error stuffing it all up.

Cheers,

Bill B.

[Paul Unger]

True--never say, "Only an idiot could / would X", because some day he will . . .

My point, though, was that wings aren't as flimsy as we might think. They're built to flex / flap / whatever-you-want-to-call-it (and yes, metal does get tired), and while clear air turbulence may be hard to avoid, most pilots can pick out (and hopefully avoid) a cat5 hurricane . . .

[rkawakami]

<snip>... all the over-engineering in the world won't stop simple human error stuffing it all up.

As in CFIT, right? I thought that was a very unique way of categorizing a certain type of pilot error .

[jamerslong]

i agree, you fat finger something and you can cause major problems. i had a pilot destroy a generator clutch because he deactivated and reacitvated the power too fast. ive seen a plane crash because they forgot to lower the flaps. (wonderful training video)

Airplanes go through DEPOT maintainence at a set interval, but depends on location.

DEPOT is where they rip the jet apart all they way down to the Skibbies and replace worn parts, we have a jet that flew lopsided because the wing was warped from a spoiler becoming stuck open. it flew almost everyday until it went to depot. never any problem, it became a training task to fly the jet.