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U.S. FAA requiring inspections for cracks on some 737 NG planes

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Unexpected cracking found on critical Boeing 737 Next Generation part


by Charlie Harger | KOMO Newsradio 

Friday, September 27th 2019
 

Boeing engineers and safety investigators are scrambling to find out how many Boeing 737NGs have cracked 'pickle forks' after finding several in the jets.

A pickle fork is the part that helps attach a plane's fuselage to its wing structure. It helps manage the stress, torque and aerodynamic forces that bend the connection between the wings and the body of the jet.

Engineers design pickle forks to last the lifetime of the plane, more than 90,000 landings and takeoffs, a term known as "flight cycles" in the aviation industry, without developing cracks. There could be dire results if the pickle fork system on the jet fails in flight.

During a recent inspection, workers found a severely cracked pickle fork on a Boeing 737NG. The plane is relatively young, having logged approximately 35,000 flight cycles when the damage was found.

 

A retired Boeing engineer who asked to remain anonymous tells us, "It's unusual to have a crack in the pickle fork. It's not designed to crack that way at all. Period."

He says it's particularly concerning because it was found so early in the plane's service.

Another source tells us Boeing quickly reported the issue with the single plane to the FAA last week, and now more planes with similar cracking have been found.

We're told this is very much an ongoing investigation, and that it's unclear whether or not this is a widespread issue.

 

 

BREAKING: Cracks found in critical part (called a pickle fork) that keeps wing attached to 737-NG (not MAX) fuselage. One found earlier in month, now more on other planes. Found early in plane's lifespan. Boe & FAA scrambling to find extent of problem. @KOMONewsradio #KOMONews

View image on TwitterView image on TwitterView image on TwitterView image on Twitter
 
 
 
 

Boeing confirmed to KOMO Friday that there is a cracking issue.

"Safety and quality are our top priorities. Boeing has notified the FAA and been in contact with 737NG operators about a cracking issue discovered on a small number of airplanes undergoing modifications. No in-service issues have been reported. Over the coming days, we will work closely with our customers to implement a recommended inspection plan for certain airplanes in the fleet. This issue does not affect any 737 MAX airplanes or the P-8 Poseidon," a Boeing spokesperson wrote.

The FAA also confirmed the inspections, telling KOMO, "The FAA will require operators of certain Boeing 737NG jetliners to conduct inspections for structural cracks. Boeing notified the agency of the matter after it discovered the cracks while conducting modifications on a heavily used aircraft. Subsequent inspections uncovered similar cracks in a small number of additional planes. The FAA will instruct operators to conduct specific inspections, make any necessary repairs and to report their findings to the agency immediately."

No one has been injured, and there have been no reports of issues on 737s that flew with the cracked equipment. It's a near certainty that people flew aboard the jets with the cracked pickle forks before the issue was discovered.

We're told this is an issue that is being taken seriously by the FAA and Boeing.

The pickle fork is essential to the safety of the plane and an in-flight failure could be catastrophic in the worst-case scenario.

A government source says that until the scope of the problem can be understood, it's difficult to tell what corrective actions will need to be taken. It could be anything from visual inspections of all 737NGs, or more unlikely, a grounding of the planes for further inspections. Investigators are deeply concerned about the cracks developing so early on in a the plane's lifespan.

Engineers say the inspection process itself is fairly straightforward and fast. 737NGs are the generation of models made prior to the 737 MAX. The 737NG is the model designated as 737-600, 737-700, 737-800, or 737-900. It started production 1996. The last one rolled off the factory floor this summer in Renton.

Light cracking is occasionally found in pickle forks, but it's very unusual.

Engineers say fatigue cracking, once initiated, grows every flight.

If a slight crack is discovered during a routine inspection, engineers run a scenario for how much they expect it to grow under typical conditions, then re-inspect at prescribed intervals.

"A crack like this is similar to when you see a crack in a coffee cup handle," the retired engineer tells us. "You can likely continue using the cup several more times, but there's always a risk that handle will break off and hot coffee will wind up in your lap."

Teams in Seattle and Washington, D.C are working on this. A source within the federal government says FAA inspectors were excited and happy to get the call from Boeing.

The source says they are "...elated that the bloodline of safety is alive at Boeing." That same source worries about how economic concerns for Boeing impact safety.

Just this week, Boeing re-organized its management structure when it comes to safety. There's even a committee on the Board of Directors now with direct oversight of safety.

Until the extent of the issue is discovered, it will be difficult to determine what maintenance crews will need to do. So far, there have been no government orders for mandatory inspections.

Boeing and the FAA will want to know why the pickle forks are cracking, and why it's happening so early. We're told it could be something as simple as a manufacturing flaw with a small number of planes and not something widespread.

This could be a pain for scheduled maintenance on planes. We're told a "fix" to a pickle fork with extensive of cracking will require mechanics to remove and replace the pickle fork fitting. It stretches around 25% of the circumference of the fuselage. A Boeing 737 has four pickle forks.

The retired engineer tells KOMO the cracks were really surprising, used an expletive, then said, "This is not good news," and added, "It's really urgent to investigate."

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there has to be a cost associated with the inspection. Of course the inspection would be NDT but what would need to be removed to give access?  No doubt that WestJet will be right on it and inspect their aircraft buy it is jet another blotch on Boeing. The following story talks about a "heavily used aircraft" but the original story talked about a relatively "Low Use Aircraft".  Scary indeed.

More woes for Boeing 737 as cracks discovered on some planes

There was more bad news for Boeing's 737 line of aircraft late Friday as the U.S. Federal Aviation confirmed it would require some operators of the jetliners to conduct inspections for structural cracks, following recent discoveries of premature cracking.

U.S. FAA is requiring some operators to inspect their aircraft and report back

Thomson Reuters · Posted: Sep 28, 2019 7:39 AM ET | Last Updated: September 28
 
westjet-aircraft-at-gate-yxe-saskatoon-a
One of WestJet's many 737-800 aircraft sits at a gate at Saskatoon International Airport. Manufacturer Boeing says a small number of the same generation of plane has exhibited structural cracking. (Albert Couillard/CBC)

More bad news for Boeing's 737 line of aircraft: The U.S. Federal Aviation Administration said late Friday it will require operators of some 737 NG jetliners to conduct inspections for structural cracks and make repairs as needed following the discovery of cracks on a small number of planes.

The FAA said Boeing notified it of the issue "after it discovered the cracks while conducting modifications on a heavily used aircraft." Subsequent inspections "uncovered similar cracks in a small number of additional planes." Boeing said on Friday it has been in contact with 737 NG operators about a cracking issue, but added that "no in-service issues have been reported."

 

Neither the FAA nor Boeing immediately said how many planes were impacted by the required inspections.

The 737 NG, or Next Generation, was introduced in 1997 and is the third-generation version of the best-selling Boeing airplane. It includes the 737-600, -700, -800 and -900 models and is operated in Canada by WestJet and Air Transat but not Air Canada. There was no immediate indication that either airline's fleets were affected.

Its successor is the 737 MAX series, which was grounded in March after two fatal crashes in five months, but which is not affected by this issue, Boeing said.

The FAA said it would ask operators of the NG to "report their findings to the agency immediately" after completing inspections. Boeing said "over the coming days, we will work closely with our customers to implement a recommended inspection plan for certain airplanes in the fleet."

KOMO News reported on Friday the issue involved cracked "pickle forks" in some 737 NG jets. The pickle fork attaches the plane's fuselage, or body, to the wing structure and manages forces. A failure of the part in flight could pose a serious risk. KOMO said workers found a severely cracked pickle fork on a Boeing 737NG earlier this month.

Transport Canada had not issued an online civil aviation safety alert about the issue as of early Saturday morning. 

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The article says the MAX isn't affected. Would they have used the same part as the NG or are the differences between the two such that the MAX would have a newer/different version?

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7 hours ago, moeman said:

The article says the MAX isn't affected. Would they have used the same part as the NG or are the differences between the two such that the MAX would have a newer/different version?

Or more likely, not enough hours to develop any cracks.  

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I wonder if there are NGs in Canada with over 30,000 hours or over 22,600 flight cycles?

FAA to order inspections on 737NGs after 3 planes found with cracked critical equipment


by Charlie Harger | KOMO Newsradio 

Monday, September 30th 2019
AA
7bd1dd6a-8b5a-4259-bf50-06c20aabd64c-large16x9_MGN_1280x720_90906B00HABLF.jpg?1569877462187
FILE -- FAA to order inspections on 737NGs after 3 planes found with cracked critical equipment (Photo: American Airlines via MGN Online)
 
 

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.

The results of the cracked equipment, called a "pickle fork," could be catastrophic in a worst-case scenario. Engineers warn it could cause a plane to crash in extreme conditions.

Inspectors recently uncovered an issue with the "pickle fork" on multiple 737NGs. It's a part that helps keep the wing of the plane attached to the fuselage, and absorbs the stress from bending and aerodynamic forces.

It's not supposed to crack at all during the planes expected lifespan of 90,000 takeoffs and landings, which is known as a "flight cycle" in the aviation industry.

 

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.

The FAA is expected to issue the order sometime this week. Airlines will be required to report their findings to the agency.

U.S.-based airlines that fly 737NGs with high-flight cycles include Southwest, Alaska and Delta Airlines. One analyst says this could cause major hassles for those airlines and others.

Alaska Airlines tells KOMO it has 166 737NGs. A spokesperson tells us “at this time we have no information to indicate there’s any immediate risk to our 737NG fleet," and that the company is awaiting orders from the FAA. It says it will comply fully with the agency's orders.

A Delta Airlines spokesperson says, "Delta teams are working through what aircraft may require additional inspection work. No operational impact is expected."

Both airlines say safety is their top priority.

A Southwest Airlines spokesperson says the company flies around 700 737NGs.

"We are aware of the reported issue and to date, have not had any unusual findings associated with the pickle fork on our 737 NG aircraft," she says. "Once we receive additional guidance, we will fully comply with any directives by completing required checks to ensure the continued safety of our aircraft. ...with a fleet of 750 planes and 4,000 flights a day, we have a rigorous and well-run maintenance program, and we work to continuously enhancing that program based on our own data as well as data that is shared by our manufacturers and industry partners."

The spokesperson says the company is awaiting official orders from the FAA.

Boeing says it's working closely with airlines and operators, and "this issue does not affect any 737 MAX airplanes or the P-8 Poseidon," a Boeing spokesperson wrote.

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Quote

Boeing says it's working closely with airlines and operators, and "this issue does not affect any 737 MAX airplanes or the P-8 Poseidon," a Boeing spokesperson wrote.

Why? None could possibly have this many cycles or different parts? Given that the P-8 Poseidon is described as:

" A derivative of the Next-Generation 737-800, the P-8 combines superior performance and reliability with an advanced mission system that ensures maximum interoperability in the future battle space. "

and it's mentioned in the same breath as the MAX, it sounds like the same part is used in both.

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The Poseidon includes structural upgrades because it is a maritime patrol platform. Standard 737's are not built to handle hour after hour of operations in the turbulence you typically find at low altitudes.

Edited by J.O.

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WestJet inspecting Boeing 737 NG for cracks after U.S. FAA directive

By The Canadian Press
Posted October 3, 2019 10:44 am
Updated October 3, 2019 10:45 am

WestJet Airlines says it is inspecting its fleet of Boeing 737 Next Generation aircraft for cracks after a U.S. regulator ordered inspections on American fleets.

Calgary-based WestJet says it has 43 aircraft that fall under an inspection directive issued by the U.S. Federal Aviation Administration Thursday.

The company says it has had no structural cracks on its 737 NG fleet and expects minimal disruption from the inspections.

Sunwing Vacations Inc., which did not immediately return a request for comment, has more than 40 of the Boeing 737 NG aircraft in its fleet.

Air Canada says it does not have any of the Boeing 737 NG planes.

The inspection order comes as Boeing remains under scrutiny after two deadly crashes led to a grounding of its Boeing 737 Max aircraft in March.

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Anyone out there who has hands on experience with doing the inspection?  Time to accomplish and what has to be removed to expose the areas of concern.  Just seems to be that 1 hr (as quoted by the FAA) is tight.  

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19 hours ago, Marshall said:

Anyone out there who has hands on experience with doing the inspection?  Time to accomplish and what has to be removed to expose the areas of concern.  Just seems to be that 1 hr (as quoted by the FAA) is tight.  

Found the answer 

Quote

The AD requires eventual inspection of all aircraft with more than 22,600 flight cycles. The FAA in the AD preamble estimated that to currently be about 1900 of the NG airplanes.

The part of the pickle fork fitting that is required to be inspected is exposed in the top forward corners of the wheel wells. With all the equipment installed near that location, it is not possible to get your head into positions that allow an adequate direct visual inspection of each of the fittings. Photos of that area that are adequate to detect the cracks have been taken by holding a cell phone up in that area. The AD requires an inspection using a borescope. There is no work required to gain access for the inspection. You just need a ladder and a borescope. It can be done in less than one hour. If you find a crack you are grounded until an approved repair is made.

here is a link to a pdf regarding the problem, the inspection and also pictures of the damaged forks.

 https://www.regulations.gov/contentStreamer?documentId=FAA-2019-0711-0002&attachmentNumber=1&contentType=pdf

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Boeing’s 737 in another pickle, Part 2  

https://leehamnews.com/2019/10/08/boeings-737-in-another-pickle-part-2/#more-31313

Interesting comment re the addition of winglets: 

Quote

The stress spectrum in the area can also have been affected by the later fitting of winglets on the NG, not foreseen in the original design of this area.

By Bjorn Fehrm

October 8, 2019, ©. Leeham News: The FAA Air Worthiness Directive (AD) for high time Boeing 737 NGs regarding cracked rear pickle forks was issued Thursday last week.

Boeing had a call with 737 NG operators today giving the latest information regarding the cracks. Of the 500 first inspected aircraft, 5% had cracks. These aircraft are now grounded. Boeing is setting up repair lines with the US line starting work on the first NG this week. The expected repair time is three weeks for the first aircraft.

737-NG-pickle-forks.png

Figure 1. The rear pickle forks carrying the main loads from the wing to the fuselage crack near the rear wing spar. Source: Leeham Co.

 

It’s the rear spar pickle forks which crack

The cracks form in the outer chord of the rear pickle forks (Figure 1) and the behind lying safety straps, just where they pass from the rear spar of the center wingbox to the fuselage side of the aircraft, Figure 2.

Rear-pickle-fork-with-crack-area-.png

Figure 2. Crack location on pickle forks and the behind lying safety straps. Right side fork shown Source: Leeham annotation of Boeing graphic.

This is also the area where the fuselage side has a cutout to let the main landing gear strut fold in with its attached wheel.

The combination of a wing center-wingbox pushing wing and landing gear forces into the fuselage in an area where the fuselage has a large cutout for the folded main landing gear makes this area complex regarding forces and how these work the parts during flights.

The stress spectrum in the area can also have been affected by the later fitting of winglets on the NG, not foreseen in the original design of this area.

Winglets change the pressure distribution of the wing to a distribution spreading further outboard, by it increasing the wing root bending moment.

Repair line started, parts production critical, temporary repair investigated

The results of the first week of inspections are 5% of the inspected aircraft have cracks with the lowest flight cycle aircraft with cracks at 23,600 flights.

Boeing has commanded full speed ahead with the production of replacement pickle forks and a repair line is set up at Victorville by its AOG (Aircraft On Ground) team. The first aircraft starts the replacement of its rear pickle forks Friday. It’s expected to take two to three weeks for the first job, which also serves as the master for a Service Bulletin from Boeing how to carry out the repair. Further AOG repair lines will be set up in Europe and Asia.

There shall be 25 shipsets of pickle forks available in October which covers the aircraft which cracks found to date. The safety straps also need replacement but these are less complicated parts.

Boeing is now investigating if a temporary repair can be designed and approved so aircraft with cracks can continue to fly until they can be scheduled for repair. It’s also checking if the demounted forks can be repaired to ease the demand for new forks as the inspections find further aircraft needing repair.

The wider inspection will give statistical data so the spread in cycles for cracks can be better understood. It could be the cycles shall be counted from when Winglets were fitted to the aircraft. This is one of the areas which are now needing further work and data to understand better.

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I get that the MAX is unaffected right now because it's new and none have enough cycles to be of concern. But are these same parts installed on the MAX? If so, how do the new engines affect the stresses put on the parts in addition to the winglets?

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Boeings response.."uhhhhh!!! We never thought of that"

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I’m wondering now about other models that had winglets added after the original design, like the mighty 767?

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One has to wonder if the Pickle Fork design was ever changed from the -100 all the way to the Max.  The airframe has gone through significant changes over the years and this is a fundamental structural component.  Was the NG ever subjected to stress to failure testing? or did they rely on the original load tests?

 

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4 hours ago, conehead said:

I’m wondering now about other models that had winglets added after the original design, like the mighty 767?

does the 767 use the same pickle fork method?

 

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I still maintain that the 737 airframe has surpassed its viability.

The airframe should be discontinued and replaced with a clean slate design aircraft.

Boeing has proven that there are limitations on adding new technology engines and systems to the aircraft without significant issues.  time to retire it.

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53 minutes ago, boestar said:

does the 767 use the same pickle fork method?

 

I do not know...

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2 hours ago, boestar said:

I still maintain that the 737 airframe has surpassed its viability.

The airframe should be discontinued and replaced with a clean slate design aircraft.

Boeing has proven that there are limitations on adding new technology engines and systems to the aircraft without significant issues.  time to retire it.

Not saying I disagree with you, but what do you do with the existing aircraft and the 4,000 or so orders for the Max, not to mention the planning that must have been done in anticipation of taking delivery? Something of a "too big to fail" situation ??? 🙄

 

Edited by Innuendo

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1 hour ago, Innuendo said:

Not saying I disagree with you, but what do you do with the existing aircraft and the 4,000 or so orders for the Max, not to mention the planning that must have been done in anticipation of taking delivery? Something of a "too big to fail" situation ??? 🙄

 

Perhaps the US Military will take them on. 😀😀

image.png.8f739025ac7a0d98af326393c6928dfa.png

Military models[edit]

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https://simpleflying.com/southwest-737-pickle-fork-cracks/

Pickle Fork Cracks On Two Boeing 737 Aircraft

It’s more bad news for Southwest Airlines as it has been revealed some of its aircraft have been identified to have pickle fork cracks. The discovery has caused the American airline to ground two of its Boeing 737 NG aircraft.

Pickle forks on Southwest Airlines aircraft

The issue was reported to the FAA and Boeing on Tuesday this week. A spokesperson for the airline told KOMO News that the cracking was found during an examination of all its Boeing 737 NG in compliance with an Airworthiness Directive issued by the Federal Aviation Administration (FAA). The spokesperson confirmed:

“During our inspections of the high-cycle NGs, we did not find abnormalities on the vast majority of our inspected fleet but did identify signs of cracking on two aircraft. Southwest removed the aircraft from our operation and reported the findings to Boeing and the FAA. The aircraft will remain out of our schedule until the maintenance items have been fully resolved, and we do not have a return to service timeline for the aircraft.”

The issue with pickle fork cracks is that the entire structural integrity of the aircraft is at risk. It was essential for Southwest Airlines to remove these aircraft since pickle fork cracking can cause additional stress, torque and improper management of aerodynamic forces. Had this issue not been detected, the results of pickle fork breakage could have been catastrophic.

How will this impact Southwest?

This development in the tale of the Boeing 737 does not bode well for Southwest. It has already experienced cancellations of an estimated 30,000 flights since the 737 MAX grounding which it says has cost its members around $100 million. What will this mean for Southwest’s services?

The grounding of two of Southwest’s 737 NG appears to be a repeat of the bad luck it has already faced thanks to Boeing. The grounding will see flights canceled, schedules reshuffled as well as likely paying for replacement aircraft or pickle fork repairs.

But already the 737 pickle fork directive has cost the airline. A 2-hour inspection and subsequent report are estimated to cost about $170 per aircraft. And Southwest Airlines says its Technical Operations team still have more aircraft to investigate.

It is not yet clear which of Southwest Airlines’ 737 NG have been removed from service or how many of the four pickle forks have been identified on each aircraft as cracked. Southwest Airlines have not issued a statement about the case.The grounding has already cost the airline and there is uncertainty about the future.

The FAA’s pickle fork directive

The FAA last week issued an Airworthiness Directive for 1,911 aircraft to be examined with potential pickle fork issues. Cracks were identified in the pickle fork component on a Boeing 737 NG during a passenger to freighter conversion. It was reported to Boeing and the FAA and proved not to be an isolated instance. Pickle fork cracks were then identified on numerous other aircraft including Southwest’s own.

The FAA’s directive was issued for Boeing 737-600, -700, -700C, -800, -900, and -900ER series aircraft. Those which had completed 30,000 flight cycles were to be examined within seven days. The pickle fork – the component attaching the wing structure to the main aircraft fuselage – is manufactured to last 90,000 flight cycles. But issues have now been found on aircraft which have done far less mileage.

Southwest operates some 752 Boeing 737 according to Planespotters.

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15 hours ago, Innuendo said:

Not saying I disagree with you, but what do you do with the existing aircraft and the 4,000 or so orders for the Max, not to mention the planning that must have been done in anticipation of taking delivery? Something of a "too big to fail" situation ??? 🙄

 

lets see what the fallout is after the fact.  I am just saying STOP selling the thing and make something better and of this century.  Every product (except toilet paper) has its life cycle.  the 737 has reached the end.

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2 hours ago, boestar said:

lets see what the fallout is after the fact.  I am just saying STOP selling the thing and make something better and of this century.  Every product (except toilet paper) has its life cycle.  the 737 has reached the end.

You know that’s not going to happen. 

I believe though that it’s the end of the big orders. I doubt they will build all that’s ordered now and will start a clean sheet aircraft after the dust is settled. It’s really not a bad aircraft just has too many compromises inherent to its age. 

It’s really the same problem that Airbus has with the A320 series just not so pronounced. Some carrier, perhaps even Southwest is going to make a huge order for the A220 and that’s when things will get interesting. 🤔

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