Back to Squawk list
  • 67

Video of B787 wing flex

A video from cabin showing the B787 wing flex during spoiler deployment. ( 기타...

Sort type: [Top] [Newest]

I remember when the 777 tests were done. The wings were pulled 24 feet above its normal position before they broke during a full scale test. I believe it was half a million pounds of pressure on each wing, (that's equivalent to the weight of a fully loaded 777 on each wing!! ) until both wings broke at the predicted position. Also on the older 747, that was pulled to 28 ft of deflection before it broke after an expected 7ft deflection in heavy turbulence and a design break point of 21ft. So when it didn't break they just kept pulling till it gave in.
Super cool video of the trip7 wings busting, I can still vividly hear that loud noise!
NOTHING TO DO with spoiler deployment. The deployment is contemporaneous with the nose dropping, which drastically reduces the angle of attack on the outboard wing section. Note, too, that the spoilers aren't anywhere near the deflected (outboard) part of the wing.
dee9bee 3
I agree. The win is no longer producing lift, at least not to the extent it was before landing.
rjb4000 2
Nobody is claiming the wing flex is due to spoiler deployment.
You guys are both right,but that is coming from the first line of the story. The wing does flex back down but not because of spoiler deployment.
see video description under title
rjb4000 2
He's just saying that it's happening at the same time as spoiler deployment.
Not entirely true Steve, although we're sort of arguing over semantics over "cause" of the flex. The wing flex immediately ceases because of a rapid loss of lift on the wing. You are correct that that is largely because of the change in AOA on the wing as the nose comes down at touchdown, but the spoilers are also dramatically spoiling the lift, as is (to a much lesser extent) the decreasing airspeed, etc. Bottom line, a BUNCH of different things happen right at touchdown, all of which contribute to the wing lift decreasing.

As for your comment about the spoilers only being inboard. True, but the ENTIRE wing is deflecting. Not JUST the wingtip. Spoiling the lift inboard is still contributing to the lowering of the wingtip. Just like if you stick your arm straight out and pivot your arm only at your shoulder. Your fingertips still raise and lower too, even if you don't move your wrist at all.
I remember landing in a very windy/stormy CYYT in an Air Canada DC-9 and being amazed by how much the wings flexed. The conditions were bad enough that they cancelled my flight in an Air Atlantic BAe-146 and put me on the DC-9. The -9 was nearly empty, I was right over the wing. It was crazy! Love this video though. They don't call spoilers "lift dumpers" for no reason!
I will never forget the wing flex in a DC3 during flight 1953 RAF Castle Bromwich to Derby Airport. It either put you off flying or encouraged you to continue the old maxim 'Never jump from a servicable aircraft' I never did, I'm now 72 and going well but missing flying.
Many years ago over the Bosforus in a SVC10 we hit very bad clear air turbulence. The wings were flapping like a bird's. The wingtips at least 2mtrs deflection up and down. We lost a lot of height. The Capt was very concerned and gave all the pax a mini spirit. He said that had the a/c been a 707 the winfs would have come off!
707 wing was designed for 7' tip deflection in up and down direction.
My best "flex" story is sitting in the last rear row of a Stretch-8 looking forward in what was probably moderate turbulance and the fuselage appearing to be a narrow tube drastically bending up and down and feeling very considerable up and down movement.
mariofer 4
MD-80 during taxi from the last row. Looks like the thing is made out of rubber.
It will stiffen up when pressurized. Also, like a ship, if it didn't flex it would snap in two. Same with a wing--aka a B-52 or C-5A.
The Delta Airlines DC-8 71 seemed a little wiggly when sitting far aft.
Watch a video of a B-52 taking off, there's quite a bit of flex there too.
If you see the manufacturers wing testing videos on you tube they apply a static wing force both upwards & then downwards till the wing fails, the amount of stress it is built/designed/tested for is simply incredible. If the flex & capability was not so, the wings would literally fall off. In contrast the F21(Sukhoi) is designed for 12G forces, which means the pilot would pass out (due to the G force) before the wings can even come near failing.
The 787 is in a class by tself as far as wing flex goes as so much attention has been called to it, but all other aircraft have a certain amount there too that goes unnoticed as is evidenced by the comments here. We don't think about a seemingly inflexible object moving like that. Due to construction, I was stopped the other day on a long 4lane river bridge. The other lane was open and it was plumb scary sitting there as other traffic passed and I just sat just sat there literally bouncing.
A classic example of flex when you don't want it. Galloping Gerity

One engineer was heard to say "I never knew concrete could bend like that"
There was a tad of steel in there
IMHO, more than the current 787 fleet. Maybe the final fleet too.
Reminds me of one of my first flights on a commercial jet, taking off on a stormy day, and maneuvering around/between storm cells. I remember the event, but not what type of plane it was, about 40 years ago. Maybe a Boeing 727? The wings and engines moved so much I was very surprised - much more flexing than this video! I remember the engines moved about 5 feet up and down compared to the wingtips.
My guess would be a Boeing 707 since you seen the engines on the wings?
I'd have to agree. You didn't have that much flex in a 727. Flying on memory but the 707 had several feet built in
That was about the only bad thing I have to say about the 727, the wings were TOO rigid. I lived in 727 wings for years, fixing cracks, leaks, fasteners, but was still a great bird.
Can't recall whether it was a 4-engine or 2, but it must've been a 4 I think. I was up near the front, and I remember looking back at the engine(s) and being surprised how far out in front of the wings they were, and then the movement in the turbulence was what I'd call extreme. The wing root connection was really stressed that day, but maybe it was 'normal'.
The engines are only held on by maybe 4 to 6 bolts. JetMech24, you can probably tell us. Anyhow, the engine has to flex or it would snap off. It flexes both horizontally and vertically. Remember also, that engine is producing tons of thrust that is transferred into the wing. That plus turbulence puts a bunch of strain on the mounts. They're hardened steel. Titanium? The mounts are designed so that if the engine comes detached in flight, it should go up and over the wing. Engines have come off in flight and the aircraft safely made it down. Unfortunately, that DC-10 at O'Hare years ago wasn't so lucky.
I know there was a predetermined cause for that accident, that had it been fixed that would not have happened, but that was also a case that going by the book led to that crash. They determined that the pilot had speed and could have sustained flight but the checklist told them to pull back on speed/power. They did, they crashed. Checklist were revised after that. Sometimes you just got to take the seat of your pants and fly the plane.
Fly the airplane. You are allowed to fly the airplane. Fly first and other items will be in their time. Screw your sim training and the checklist. They can't cover every emergency. I think there was some delay in realizing that they actually were missing that engine. I think it also damaged the wing. You're right. Fly first--do whatever it takes.
Yeah, I think that is why they went to the checklist, best I remember; they were probably thinking standard EO procedure, but again, fly the plane.
Unfortunately never got to work on 707's, but from 727's and up, the engines are held on by 3 bolts, two forward and one aft.
Yep. Like on a wing mounted engine, if the aft one is the first to give, the engine will torque upwards until the forward bolts give.
Unfortunately, Peter, the DC-10 engine and wing design is such that if an engine breaks away it will roll right over the leading edge of the wing...virtually rendering the airplane inoperative at that point. Boeing a/c, on the other hand, are built so that if an engine breaks away, it will drop and go under the wing not to compromise fuel tanks, hydraulics etc.
You can't lump all engine separations into one. I really don't know the validity of your statement but I think it will depend on power setting, which mount fails first--forward or rear and probably how bad turbulence was at the separation if that was the cause of a failure. AA191 was under full TO power and the mount had a fracture that failed. That engine was going over the wing no matter what. It didn't just fall off. It tore off and took out the LE slats. If, on the other hand, an engine simply falls off, it will likely go under the wing. Keep in mind, I'm no expert on this--just using some common sense.
I think it's as were were talking about above; design and SHOULD DO is 2 different things. According to the checklist for standard EO procedure, they should have pulled back power, BUT they were FLYING. They didn't crash until they followed the checklist. Regarding that, that really had no way of knowing the severity of the situation, at least at first. Seems to me there was a maintenance issue or something with either the engine and/or the pylon that was already identified and was either patched or not done. Bunch of folks dead to keep from spending $.
If you want to see wing flexing, fly a modern 25 metre span, carbon-fibre sailplane. 2+ metres at the tip is normal, especially during 45° thermalling turns or during a winch launch where the wing looks like a banana.
I will never forget the wing flex in a DC3 during flight 1953 RAF Castle Bromwich to Derby Airport. It either put you off flying or encouraged you to continue the old maxim 'Necer jump from a servicable aircraft' I never did, I'm now 72 and going well but missing flying.
One of the reasons why I like sitting over the wing.
None of the modern day airliners hold a candle to the wing flex of the Air Force B-52 bomber. From a sitting position on the ground to their position inflight, each wing tip flexes upward approximately 8 feet. On takeoff, the wing of the aircraft is flying well before the body ever leaves the ground.
I can't wait for my fist flight next saturday
smoki 2
There are few wings that flexed more than that of a stretch DC-8-73 when its "spoilers" were deployed. No, not wing mounted spoilers but the inboard engines were brought into reverse while at altitude for what was affectionately referred to as a "slam dunk" descent. Trust me, it came down in a hurry so much so that Air Traffic Control would question before hand with "Can you make it down" which was soon followed with "that was impressive" as they handed you off to Approach Control or Tower.
That's a new one on me.
me too, but sounds like
Hey ol' Preach--in my turboprop days you didn't dare put one in reverse!! Just like most modern jets, there are lots of safeguards to prevent you from deploying the buckets. On the ERJ-145 you had three systems to protect you from deploying the buckets in flight. Maybe one of those on your 75 could do it? Those engines that don't use buckets can maybe do it? On those, you only reverse the fan air. With buckets, you reverse all the air, fan and core.
I'm a thinkin' there are safeguards built in. Buckets or otherwise, it ain't nothing I'd wanta Every ounce of training I ever had on anything made it a no-no.It's been too long ago but you could have probably done it on a 707 as there were no preventative safeguards at all, but as in one of the other stories posted here about go rounds, they can be deployed and not come back to you ASAP, and that is a handful of major problem that I just never wanted a part
I always taught and Flight Safety Intl' did also that once you are on the runway and reverse is used, you never go around or land and go, in this case. If a mower crosses in front of you, either hit him or go into the grass.
Well, that's kinda how it was here and I sure wouldn't pull one in flight. I have had ATC want me down quickly before but I never even thought about anything like that. Failure of reverse to come back was what caused that 727 crash in that other post here.Different strokes for different folks I guess.
Having rode a bunch of DC8s back in the early 70s between Vietnam and the US, I'll never forget the approach we made into Tahn Sa Nhot airbase on my initial arrival in Vietnam. We were on one of the many charter airlines that contracted with DOD to transport military personnel back and forth between VN and US. About 20 min before arrival, the capt came on the PA and announced that the base was being shelled therefore we would be doing a non-standard approach.. To put it bluntly, it felt like riding in a runaway elevator. We dropped like a rock! I don't know what all was reversed in the air, or deployed, but damn.. that airplane lost a LOT of altitude in a VERY short time. About the time the plane looked like it was gonna crater in the rice paddy, engines went to full power and voila! there was the runway.. After a frantic thrust-reverse, we rolled off the runway into a sandbagged revetment and "evacuated" from the plane into a bunker next to the revetment.. Quite a scary way to be introduced to Vietnam... A bunch of us "new-meats" were pretty shaken, but several returning guys said "wow! that was better than a roller-coaster"... I was somewhere in-between...
pully6 1
Great story mate thanks for sharing! Most of my generation (I'm 26) has no concept of what it must have been like!
I don't know if that's as bad as watching new meat come off an inbound and stacked up body bags going back out on the same plane.
Amen. Vietnam FAC 1970.
I never saw that but once. I did a tanker hop out of South Korea, sortied going in and RON at DaNang. Parked us on the ramp next to the PanAm that came in ahead of us. As it was deplaning, they were loading body bags into the hold. My understanding they would go to the West Coast, put in a coffin and sent home from there. I guess they could stack more in there in the bags.Cheaper that way.Heck of a sight for the newbys.
True story. Jumping a ride on a C-141 Da Nang to Kadena, I went in back and sat on some boxes to have a snack. The crew chief said please don't sit there. Those are dead soldiers going home. I was never so humble in my life. I really didn't know the whole plane was loaded with those boxes.
You know, I guess this got way off topic but I still remember changing to civvies after separation at McChord and paying the higher fare home just to keep from traveling in uniform and having to put up with all that crap going on back then
Yep, here are two old farts talking about something that has nothing to do with wing flexing! What the heck.
What was he doing with the camera turned on, or don't the rules apply to him?
What a cool video! Thanks for sharing.
For all you "Wing Flex" enthusiasts out's an F.Y.I.....
The 787 Wing Flex Test increases a load in 10% increments up to 100% load, then it's increased to 150% limit and again until it destructs beyond the 150% limit. The 787 exceeded all expectations, as required by the FAA. All Commercial AC must withstand at least 3 seconds of 150% expected loads on all major structures. The wings would deflect a full 26 feet at 150%. In comparision, the 777 wings deflected 24 feet at 154% max load before they snapped!
It exceeded expectations AFTER failing and being modified.
Isn't that the purpose of all tests of an aircraft? If it fails...modify it until it over-exceeds! What matters here is the end result of the modification. A well built aircraft.
That's what I thought. It ain't always gonna work right the first time.
The 777 only took once, difference between sticking to what you know and trying to re-invent the wheel.
flyerh 1
While landing in Bangkok in a China Airways old 707 the pilot foolishly let down thru a Charlie Bravo. Due to turbulance people were screaming, barfing and doing a lot of praying. I told my wife "Don't look". In addition to turbulance the plane was thrown from one severe yaw position to the other. I foolishly decided to look outside only to see the wings flapping like a bird. What really startled me were the engines literally whipping up and down. We landed hard several times on touch down. Next day in Manila, same carrier and I suspect same plane, an outboard engine fell off on touch down, with loss of life. I wish you sky jockeys wouldn't do that to us! flyerh
I guess there are some in every crowd and that is definitely not the norm. That said, I wasn't there, and it may have been a necessity to get down, as far as wx goes. You get bit in the butt sometimes and gotta do what you gotta do, but it ain't anuthing you want to do on a regular basis, at least I wouln't want to do it..(from a retired 707 driver)
Great work from the metallurgists. These modern materials are almost magical in their properties
The wings on the 787 are composite, not metal.
I was browsing through old accident records when I came across one I hadn't heard of:
Might interest a few of you? It's about a 747 crash where the wing-flex got out-of-control after a lightning strike caused an explosion in a wing fueltank.
benin 1
must be scary to watch the wings bounce in turblance.
Thanks for the video. The wing lift sure leaves in a hurry. Makes my corporate CJ3 look like a play-toy. Looking forward to my first ride on the 787. Blue skies all !!
rxcw43 0
These aircraft wings made of medal and exotic material are looking and moving more and more like the feathered wings of a bird...
All wings flex when dumping lift on landing!! Even the VC10's which has one of he stiffest! The video shows nothing dramatic.
You should watch wing flex on a B52 with max loadout. That's impressive no matter how many times you've seen it
Eudokimos -2
Video was not filmed horizontally.
I am so sorry about that. I realized the camera was inclined too late.
Metal Fatigue = Many Deaths
WIngs are largely composite - not metal. Composites do not "fatigue" the way metals do.
And even if it were a metal wing, it has been widely noted in a lot of comments here that every airlier has a certain amount of flex built in.
Quite true, they just fatigue differently. The science hasn't had the history of metallurgy and I suspect there are lessons to be learned. I seem to recall some discussions of problems with composite use after the Fastnet sailboat race in 1979. Not technically aviation, but some of the boats did get airborne.


계정을 가지고 계십니까? 사용자 정의된 기능, 비행 경보 및 더 많은 정보를 위해 지금(무료) 등록하세요!
이 웹 사이트는 쿠키를 사용합니다. 이 웹 사이트를 사용하고 탐색함으로써 귀하는 이러한 쿠기 사용을 수락하는 것입니다.
FlightAware 항공편 추적이 광고로 지원된다는 것을 알고 계셨습니까?
FlightAware.com의 광고를 허용하면 FlightAware를 무료로 유지할 수 있습니다. Flightaware에서는 훌륭한 경험을 제공할 수 있도록 관련성있고 방해되지 않는 광고를 유지하기 위해 열심히 노력하고 있습니다. FlightAware에서 간단히 광고를 허용 하거나 프리미엄 계정을 고려해 보십시오..