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737NGs have cracked 'pickle forks' after finding several in the jets.

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737NGs have cracked 'pickle forks' after finding several in the jets.

Old 1st Oct 2019, 00:13
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Please reference posting #26 in this thread. The illustration shows the Pickle Fork attached to the Wing Spar.
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Old 1st Oct 2019, 04:00
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Yikes, this is not just some surface cracking:

The Federal Aviation Administration is expected to order all airlines to inspect all Boeing 737NGs with 22,600 or more flight cycles after three planes were found with critical equipment cracked all the way through. One of the three planes in question was being converted from passenger to cargo service in China. Only 15 had been inspected for the issue when the three damaged planes were found.

Most of those 737NG planes will be required to have an inspection performed within 1,000 flight cycles.

But planes with more than 30,000 flight cycles will need to be inspected within a week.
Some overtime headed your way?
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Old 1st Oct 2019, 04:15
  #63 (permalink)  
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The illustration shows the Pickle Fork attached to the Wing Spar.
Yes, it does, and generally, and in the case of Boeing jets, the wing box is enclosed by wing spars at the forward and rear faces of the wing box. So, the "pickle forks" are attached to the spars and to the wing box, as considered as a larger assembly including the spars.

Wing bending could have a small effect on the wing box to fuselage connection, in transmitting bending loads from the wing box into the fuselage. I expect that the pickle forks would also be subjected to asymmetric loads associated with yaw, where the vertical stabilizer and wing (including possible differential power) act in opposition to twist the fuselage to wing connection. I'm aware of other types where the loads applied into the airframe from the vertical stabilizer and rudder are of concern.
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Old 1st Oct 2019, 04:32
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Talking Positive G

so, to sum it up, as long as we keep positive G’s the fuselage will remain sitting on the wing box. Simples!
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Old 1st Oct 2019, 04:38
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I know of a U.S Carrier that has many 737 NG's that have more than 22, 600 cycles. Just the type of publicity Boeing needed after the 737 MAX debacle.
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Old 1st Oct 2019, 04:44
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Originally Posted by Water pilot View Post
Yikes, this is not just some surface cracking:



Some overtime headed your way?
I guess stop drilling is out of the question then!

All NG's to be inspected and so far 3 out of 15 aircraft have cracks.

With only 15 aircraft sampled that 30,000 cycle limit might drop.
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Old 1st Oct 2019, 04:56
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In case you didn't realize I have been inside the Wing Center section numerous times when I was younger. We entered thru the Fuel Tank Plate opening on the lower side of the wing center section..In Fact we had to install Fuel Cell Bladders with special lacing cord on some of our B 727's in the Center Section. So I'm very familiar with the Wing Center Section Structure and the "Bottle Bolt" castings and Bottle Bolts [also called Pins] where the left and right wings attach to the Center Section. In fact we accessed the rear Bottle Bolts thru the wheel wells and used Liquid Nitrogen / Dry Ice to shrink them before installation. The wings had to be shored before we removed the Bottle Bolts for inspection and/or replacement of the casting. I could provide more details but this thread is not the place to do it.

Last edited by B727223Fan; 2nd Oct 2019 at 05:32. Reason: incomplete info.
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Old 1st Oct 2019, 11:38
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Originally Posted by B727223Fan View Post
In fact on Heavy C Checks the floorboards are removed in the fuselage
Floorboards?

I know that the 737 is an old design but had no idea that Boeing was still using wood!
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Old 1st Oct 2019, 11:46
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Originally Posted by Speed of Sound View Post


Floorboards?

I know that the 737 is an old design but had no idea that Boeing was still using wood!
He did say “when I was younger”..
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Old 1st Oct 2019, 12:32
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It will be interesting to see what the forthcoming AD/SB will contain.
I would assume that it will require entry to the centre tank with quite a bit of sealant removal, so it won't be a 5 minute inspection.
If it wasn't for the spotlight on Boeing because of the MAX, we would probably of never heard of this in the mainstream media, these sort of problems exist on many aircraft types, it's not just Boeing products, there's plenty of similar inspections on Airbus aircraft.
@ B727223Fan, I remember the B727 well, we used to inspect the Frames that the forward wing Bottle Pin attached to, STA 740 if I remember correctly, these used to crack in the lower lobe (accessed through the Fwd Cargo Bay), the repair was either a stop drill and external stainless steel doubler or a Frame replacement.
We also used to find cracks in the frames common to the forward and aft bulkheads of the MLG wheel well (STA 870 & STA 950), these used to crack near STR 10 - STR 14 in the window belt area probably due to corrosion.
Of course at the time these were 30 year old aircraft so some defects were to be expected.
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Old 1st Oct 2019, 14:27
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Wing Center Section Structure and the "Bottle Bolt" castings
I would expect structural components in Boeing wings to be comprised of forged parts, rather than castings. The weight penalty, combined with less predicable mechanical characteristics of castings would make them undesirable for such an important structure.
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Old 1st Oct 2019, 15:07
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Originally Posted by Speed of Sound View Post
Floorboards?

I know that the 737 is an old design but had no idea that Boeing was still using wood!
Allegedly as recently as this century they were building planes (787) with plywood doors...
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Old 1st Oct 2019, 15:20
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Originally Posted by infrequentflyer789 View Post
Allegedly as recently as this century they were building planes (787) with plywood doors...
Oh yes, the famous fake Dreamliner launch in 2007!
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Old 1st Oct 2019, 15:31
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Originally Posted by Pilot DAR View Post
I would expect structural components in Boeing wings to be comprised of forged parts, rather than castings. The weight penalty, combined with less predicable mechanical characteristics of castings would make them undesirable for such an important structure.
its very easy to confuse a high quality casting which is painted with a forging which is painted. Especially when such is a specialized aluminum alloy..
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Old 2nd Oct 2019, 01:58
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Originally Posted by Speed of Sound View Post


Floorboards?

I know that the 737 is an old design but had no idea that Boeing was still using wood!
apparently they all do, before the airplane departs, the passengers are all onBOARD arent they, after the BOARDing process is complete...
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Old 2nd Oct 2019, 02:47
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Yes, it does, and generally, and in the case of Boeing jets, the wing box is enclosed by wing spars at the forward and rear faces of the wing box. So, the "pickle forks" are attached to the spars and to the wing box, as considered as a larger assembly including the spars.



center wing box, and what appears to be the right rear "pickle fork"

Last edited by ironbutt57; 2nd Oct 2019 at 03:09. Reason: espelligns
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Old 2nd Oct 2019, 03:15
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maybe the ones that have cracked pickle forks are the ones that took a train trip down to the bottom of a gorge
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Old 2nd Oct 2019, 03:33
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Seems the inspection is fast at one hour.

https://leehamnews.com/2019/09/30/bo...nother-pickle/
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Old 2nd Oct 2019, 04:37
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Originally Posted by Bend alot View Post
Seems the inspection is fast at one hour.

https://leehamnews.com/2019/09/30/bo...nother-pickle/
Also note the claim that inspections are to be done with a borescope-

Hint- borescopes are normally used to inspect ..... HOLES.... and ROUND things, but sometimes areas hard to see - sort of like a colonoscpy- same device. If it only takes one hour, most likely does not include removal of much- or remove a fastener and that cracks are expected to be visible. Suggest we wait for pics- drawings- or more details. AD supposed to be out in a day or so
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Old 2nd Oct 2019, 05:30
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[QUOTE=Bend alot;10584485]Seems the inspection is fast at one hour.


Thank you for posting the info link.. Much more informative than previous info.
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