Delta aircraft loses a part of the wing

[elvispilot]

A Delta 757 loses a part of the wing, wonder how bad it would have been if the engines were rear mounted

[tiger9999187]

http://i.imgur.com/59oQPGZ.jpg Photo including a leak

[elvispilot]

@tiger: the passenger who took that pic is a boss :D

[lomapaseo]

Wow right along the attachment line on all sides. When they find it they might even be able to reuse it if the attachment holes were mostly empty.

[elvispilot]

@lomapaseo : I'm no expert but I'm surprised that some of the wires didn't come off

[Heli-phile]

Wow, did the gear extend ok, major hydraulic leak on that right main gear ram!

http://i.imgur.com/59oQPGZ.jpg Photo including a leak

[oldpax]

They could make the wing piece from Perspex!!Then you could see things working!!!

[ampclamp]

Fortunate it did not do some stab or elevator damage.

[n6330v]

first time I've seen something like that. :D

[mseyfang]

Plane was Delta 2412 KMCO-KATL.

[mary meagher]

At a moment like this, keep calm and carry on! where was it going, I wonder, and how high when this photo was taken out a passenger's window....that's somebody I would call a very first class passenger!

[owen meaney]

Are we being misled?
It looks like an access panel removed for inspection.

Edit:
major hydraulic leak on that right main gear ram!What color is hydrolic oil?
Why is there a test kit attached to the ram?

[StormyKnight]

The image looks real to me at least this posted version, the jpg tiles match up between the wing & sky....
No jaggies seen, no errors noticed on the static discharge? protrusions (trailing edge, outside wing)
The photo would need to be taken & processed in raw mode & then converted to a jpg to give the same effect, but the noise levels look very similar between the wing & sky i.e. same camera used...

Of course no EXIF data provided...
Could be wrong, but....

AND..the oil spray looks very realistic! :)

[Xeque]

Can anyone here tell from the ram whether the wheels are up or down?

[t_cas]

Gear is up.

[Volume]

It looks like an access panel removed for inspection.
It definitively is an access panel (typically called shroud panel), and maybe it has been previously removed for inspection, but obviously not fastened after... There is not a single remainder of the panel in the fastening areas. To break all fasteners is highly improbable. Someone forgot to install all of them?
I assume a ferry flight without that panel is not allowed?
Some mechanic will probably have a chat with his boss now...

[owen meaney]

The image looks real to me at least this posted version, the jpg tiles match up between the wing & sky....
When enlarged, I thought the same, which led me to think of the perspective, the aircraft could be on the ground and jacked. Low cloud behind.
As someone said, it is a lot of screws to be left out/loose.

[Cameronian]

The upward curve to the wing looks natural and strongly suggestive of in-flight loading, owen meaney.

[owen meaney]

Yes indeed it does, cheers Cameronian.

Should have looked online first:
http://www.news.com.au/world/delta-plane-makes-emergency-landing-in-atlanta-after-losing-part-of-its-wing-midair/story-fndir2ev-1226857236107

[aterpster]

I suppose an ETOPS (or whatever it's called these days) wouldn't dare shed a panel like that over the middle of the pond. :eek:

[Una Due Tfc]

Owen, the hydraulic fluid (called "skydrol") is pink/purple to make a leak easier to spot

[EDMJ]

There must be an embarrassed person out there with a pocket full of fasteners.... :E

[Tailspin Turtle]

Once upon a time, many years ago, I boarded a Delta jet at SFO somewhat early. I had a seat on the aisle in an emergency exit row. I was just making my nest when three Delta employees showed up and asked the lady in the row across from me if she would mind getting up for a few minutes. She got up and they proceeded to open the exit door (it was a lot heavier than I would have thought) and all get out on the wing. They stood there looking down at a small access door about six to ten feet out from the fuselage and then one of them, presumably the mechanic (engineer to non U.S. readers), took a roll of duct tape (aka speed tape) out of his overalls and proceeded to carefully apply tape along the edges of the door, overlapping both the door and the wing. He stood up, the other two (presumably an inspector and a supervisor) nodded their heads, and they all clambered back inside. It took a little jiggling and manhandling to get the door back in place but they did, thanked the lady, and departed the airplane. Passengers kept boarding through all of this.

The folks on that side of the jet kept the rest of us informed as to the condition of the duct tape all the way to Dallas...

[JW411]

There is just a slight difference between speed tape and duct tape. If you don't believe me, go out and buy some speed tape but make sure you have a bank loan in position first.

[Fargoo]

Are we being misled?
It looks like an access panel removed for inspection.

Edit:
Quote:
major hydraulic leak on that right main gear ram!
What color is hydrolic oil?
Why is there a test kit attached to the ram?

Not test kit, thats the flexible hydraulic hose ripped off its mounting.

The gear would still come down under gravity extension if the ram doesn't work.

It looks like there are a few sheared fasteners on the edge nearest the window and on the aft edge nearest the window, possibly job started and not handed over properly. Composite panel would rip right off on take-off although I'd expect it to pull over the screw heads rather than shear them off.

Great photos from the passenger though!

http://avherald.com/h?article=471862b4&opt=0

[StormyKnight]

I would image a fair bit of force on that panel during flight...someone calculate that for me....
weight of the aircraft/wing area would give the weight per square inch then multiply by the area of the hatch...

What's the number?

[HarryMann]

.. afew tons I expect!

Nobody has even said yet what type of aircraft it is...

Wasn't it Delta debris that supposedly ended Concorde's career, quelle chagrin!

[elvispilot]

@harryman : It's apparently a 757

[JRBarrett]

Owen, the hydraulic fluid (called "skydrol") is pink/purple to make a leak easier to spot

Skydrol is purple when concentrated in one location, like a reservoir, but when it spreads out over a surface, it's almost colorless.

Unlike MIL-H-5606, which leaves reddish stains wherever a leak exists.

Best indicator of a slow leak or seepage of Skydrol on the outside of an aircraft is to find deteriorated / bubbled paint. It's a better paint stripper than chemicals specifically designed for that purpose...

[Lone_Ranger]

I would image a fair bit of force on that panel during flight...someone calculate that for me....
weight of the aircraft/wing area would give the weight per square inch then multiply by the area of the hatch...

What's the number?

You are talking about the aerodynamic forces?, if so the Calculation is more complex than working out wing loading and dividing by area

Firstly, its only the top skin missing, the underside of that area is still contributing a large percentage of the lift that it would produce, if the upper surface was intact.

Also it is apparently about 60% chord so aft of the CP and flow disruption
may well be quite minimal.

In all it probably had a far smaller effect on L/D than you might imagine

As for the percentage of structural strength of the wing it contributes, would, for me be a guess, so I wont bother....OK I'll bother...< 3%

[crewbag]

Too much De-Icing? :}




What would be the fuel penalty factor with such a hole?!

[Capn Bloggs]

Nobody has even said yet what type of aircraft it is...

You could try reading the first post...

I would image a fair bit of force on that panel during flight...someone calculate that for me....
weight of the aircraft/wing area would give the weight per square inch then multiply by the area of the hatch...

What's the number?
Work it out from here and let us know...
Boeing 757 - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Boeing_757#757-200)

[Spooky 2]

HarryMann it was a Continental DC10 not any DAL aircraft.:)

[lapp]

There is just a slight difference between speed tape and duct tape. If you don't believe me, go out and buy some speed tape but make sure you have a bank loan in position first.

Nice line but try again, no loan is needed for a $30 roll of Scotch 425.

[BARKINGMAD]

I hope the crew amended the Zero Fuel Mass before landing, otherwise the calculated landing mass and the load/trimsheet would have been inaccurate?

Tea but NO biscuits with flight management! ! ! ! :=

[Capn Bloggs]

Tea but NO biscuits with flight management! ! ! !
That's a bit harsh, Barking. When did you last inspect the access panels on the top of your wings? Woof woof!

[Five Green]

Wonder how much they added to V ref for that one !

Still speed taping hatches on newer airplanes

[stilton]

Seems like this sort of thing happens to Delta a lot more often than the other US Legacies.


Their older fleet is starting to creak a little.

[Una Due Tfc]

I think if the mechanic forgets to put the screws back in, the age of the aircraft has little bearing!

[lakerman]

Stilton, if you had read the article fully you would have realised that the panel normally is never removed as it is fitted with a mixture of hi-loks, rivets and fasteners. Only Boeing know why there is that mix, with a hydraulic leak a burst of pressure could push the panel up and off where the leak is situated, remember the pressure is approx 3000psi.

[lomapaseo]

remember the pressure is approx 3000psi

only while it is contained in its reservoir, not after it leaks

[Machinbird]

Quote:
remember the pressure is approx 3000psi
only while it is contained in its reservoir, not after it leaks
When a fluid is pressurized in a hydraulic system, it has potential energy. At the point where said fluid is released from the pressurized system, that potential energy is converted into kinetic energy (high velocity).
When the high velocity stream is directed at structure, the momentum of the fluid is converted to a force on the impacted structure.

With enough fluid flowing under pressure from a leak, things can get torn up.

Despite my comment above, it still looks like some sort of maintenance process got interrupted, no matter what type fasteners were used to anchor the panel.

[buttrick]

A few clues:
At the fwd inboard corner the flange is not damaged or displaced, therefore the screws were not in those holes.

None of the landings are damaged: if the screws were fitted you would expect the departing panel to rip off or damage the landings, or leave parts of itself behind.

The black bits trailing over the wing are micros witch harnesses for u/c indication/sequencing, which were attached to the inside face of the panel for support.

The fluid is probably fuel from a vent pipe or pressure sensing pipe also attached to a bracket on the inside face of the panel.

So the most likely explanation is that the panel was incorrectly / partially fitted

[buttrick]

Quote:
remember the pressure is approx 3000psi
only while it is contained in its reservoir, not after it leaks


I would hope the reservoir had a LOT less than 3000psi in it!!

Most airliners are now using 4000 or even higher, to save weight.

The hydraulic system will not have enough flow to cause the door to pop off, but a compressed air system might, but I don't think the 757 uses one, in that area at least.

A catastophic failure of an outflow valve might give enough over pressure!

[NSEU]

I'm pretty sure older gen Boeings don't have (over) 4000psi hydraulic systems.

What kind of an outflow valve are you referring to? That wing area is certainly not pressurised.

[NSEU]

For info, reservoir pressures are probably in the range of 30~50psi. And, according to Avherald.com, the aircraft was nearing top of descent when the panel came adrift. With the landing gear lever in OFF, one would think that the gear actuators would be unpressurised (except, perhaps, bogey tilt actuators).

[ExSp33db1rd]

Had a panel fly off a 747 wing in a similar position during the climb - long story, ultimately proved to be a fibreglass fillet panel but one didn't know, nor what had punched it off, gear or flap retraction etc. so I dumped fuel and landed back at the departure airport in fairly short order.

At the engineering enquiry Boeing asked why I had returned, as the 747 could fly with a panel 6' x 9' ( forget the exact dimensions ) missing in that area (Oh, really, news to me ).

The company engineer said " What's the Captain supposed to do, go out and measure it ? "

Too right, I was back on the ground, fix it.

[West Coast]

Well, in Boeing's defense, it apparently did fly, no?

[Krystal n chips]

Most airliners are now using 4000 or even higher, to save weight.

The hydraulic system will not have enough flow to cause the door to pop off, but a compressed air system might, but I don't think the 757 uses one, in that area at least.

A catastophic failure of an outflow valve might give enough over pressure

I appreciate there isn't really a lot to do in your location, at night, but even by R n N's "fly sim analysts speculation " standards, the above is a an outstanding effort.

The "door" being a wing panel, for a start, and then, the little matter of the outflow valve.

If you could provide a schematic of the, lets call it the cabin pressurisation system, that shows how the outflow valves now affect the wing structure and upper surface in particular in this case, this may well be of interest to many for whom this development is a revelation.

[henra]

When a fluid is pressurized in a hydraulic system, it has potential energy. At the point where said fluid is released from the pressurized system, that potential energy is converted into kinetic energy (high velocity).
When the high velocity stream is directed at structure, the momentum of the fluid is converted to a force on the impacted structure.


That is correct.
However, the kinetic energy of a thin stream of Hydraulic fluid will not be very high. Since Hydraulic fluid is incompressible, the pressure will immediately drop once a leak develops. There will be a sharp stream of fluid, able to cut through soft material but the Overall force it would excert on a plate will be negligeable. If we saw a small cut in the Panel I would agree. But blowing of a Panel with liquid fluid? Rather not.
If you had a leak of 5 mm Diameter at 3000PSi (if it is much bigger than that the pressure will drop immediately to much, much lower values) the force excerted on the plated would be 40kg. That won't blow off a Panel.
Even 10mm Diameter (which would cause drastic drop of pressure) would theoretically only deliver 160kg max of force.

Aerodynamic (Lift) Forces on the Panel won't be very high, either, but significantly higher than that:
At 60% chord length and only the upper surface being affected, lift contribution would be only a fraction (probably ~20%, depending on exact pressure distribution along the chord at that Re Number and AoA) of its area compared to the wing area. (anyone knows how big this Panel is on the 757? Looks like 3-4 m^2. Based on that we would be talking about the Order of Magnitude of 300 - 400kg of lift force on the panel.
That is, unless it starts to lift on the front edge first. In that case, it would catch air underneath and be blown off instantly, no mater how the rear end is fastened.
Conclusion:
Somehow the fasteners (at least at the leading edge) must have come loose/missing, for this hatch do depart the aircraft. Air pressure underneath could achieve the same but I would expect it to blow the gear doors open, first, since they will not be designed for that load direction at all - and where should it have come from?. Hydraulic pressure could cut a hole into the Panel but probably not blow it off.

Very fortunate it didn't wipe out the tail feathers on this bird. Might have ended badly.
Chances are, someone was sleeping badly after that one.

[buttrick]

A catastophic failure of an outflow valve might give enough over pressure

Just an example of something that COULD cause a door to pop off.

For the ignorami DOOR is used in many more modern /US aircraft instead of PANEL.

[buttrick]

http://i1183.photobucket.com/albums/x461/petebutt/imagejpg1-1.jpg (http://s1183.photobucket.com/user/petebutt/media/imagejpg1-1.jpg.html)

[Marvo]

Buttrick - the outflow valve is associated with the pressurisation system and has nothing to do with it! The wing is not pressurised.

I think some people are getting confused between reservoir and accumulator.

[ExSp33db1rd]

Well, in Boeing's defense, it apparently did fly, no? Yes, but I wasn't aware of that prior to the incident, not exactly laid out in the MEL, and as the panel apparently blew off as either the gear or flaps were being retracted, and vibration became obvious i.e. what other damage might have occurred, would you have continued for 7 hours over shark infested ocean ? I'm on the ground mate, sort it.

Next time - I might, might, be tempted to take a different viewpoint, but as it happened not long after a 747 had experienced a bit of fuselage skin peeling off taking a row of passenger seats with it, and we couldn't see how far in towards the fuselage the opening was .... tough, did it.

Hindsight is great.

[Krystal n chips]

" For the ignorami DOOR is used in many more modern /US aircraft instead of PANEL"

Thank you. I am always grateful to have my education expanded.....despite the minor detail of having worked on 757's for, say, 12 years....give or take....with a Hyd system px of 3000psi. And yourself, other than as pax ?

Compressed air ?.....erm, no.

Compressed N2...yes....I wonder why an inert gas would be preferred.....and please, don't try and quote bleed air as an example of compressed air.

Emergency u/c lowering.....blow down on the FJ world, for obvious reasons, but something called.....gravity...... does the job just as well.

I must though, have missed something rather unique with regard to the location of the outflow valve(s).

Are you thinking of making engineering a career....or just a passing hobby ?

Quite why the panel took off with the a/c, and departed to do it's own thing thereafter, has not yet been answered however. As yet.

[JamesGV]

It's the "inspection Panel" !
Boeing are becoming like Omega.

[buttrick]

Krystal:

At what point did I write
"The 757 has....."

I just pointed out inconsistencies in other peoples posts!

Overpressure from whatever source is a widely known cause of DOOR pop off syndrome.

[lomapaseo]

Overpressure from whatever source is a widely known cause of DOOR pop off syndrome.




some small doors/panels are designed to blow off under an overpressure. I wasn't aware that this large one was designed so with all those fasteners. Seems like there may have been other escapes if there was an overpressure in that area.

[NSEU]

Wing/Strut Blow out panels/doors are generally in the area of pneumatic ducts which run along the wing leading edges. They are usually spring-loaded and often hinged.

I have to agree with the 15 year guy. In my 40 year experience in the aircraft engineering world, riveted or screwed down panels have never been called doors.

[buttrick]

I have to agree with the 15 year guy. In my 40 year experience in the aircraft engineering world, riveted or screwed down panels have never been called doors.

Neither did I until recently, it's a modern yank thing.

[flyboyike]

Most airliners are now using 4000psi [hydraulic systems] or even higher, to save weight.



Most? I'm only aware of one that uses more than 3,000psi, and that's the A380.

[tdracer]

787 uses 5000 psi, all other Boeing '7s' use 3,000 psi. Not sure about the Long Beach (ex MacD) stuff.