More Boeing 737 NGs Checked For Wing Base Cracks


Early this month, we reported that Boeing asked airlines operating the Boeing 737 Next Generation series to examine their aircraft for ‘pickle fork’ cracks. Qantas and Southwest have unfortunately found cracks on their aircraft, and sent them for urgent maintenance.

Qantas 737-800. Photo: Vismay Bhadra via Wikimedia

What are pickle fork cracks?

If you missed the initial news, maintenance crews working on Boeing 737 NG aircraft for Indonesia’s Sriwijaya Air discovered two of their oldest aircraft to have cracks where the wings meet the fuselage of the aircraft. This section of the aircraft (the pickle fork) holds the most stress on the aircraft and is the most likely place for wear and tear.

Boeing decided to look into the earliest Boeing 737 next-generation models to see if the problem was more widespread.

Introduced in 1997, the Boeing 737 Next-Generation aircraft offered significant internal upgrades and greater fuel efficiency than the classic generation aircraft before them.

They discovered that the problem seemed to be apparent in aircraft over 30,000 flights or cycles as its term. This investigation of 810 aircraft led to the grounding of 38 more that had the issue. The crack issue is easily fixed at a cost of around $400,000 per aircraft. The plane will be taken out of service for some time but, naturally, safety is the number one priority.

The FAA announced during this issue that they are “working with the manufacturer and other international aviation safety regulators to better understand the factors that led to the formation of the cracks.”


As a precaution, airlines that operate the 737 models extensively decided to do their own investigation… revealing some troubling findings.

Southwest Airlines Boeing 737
Southwest operates a huge fleet of 737s. Photo: Southwest Airlines

Cracks found on younger models

According to, Australian airline Qantas found cracks on a 737 with only 26,700 cycles, a good 3,300 before it’s supposed to be checked over. Likewise, Southwest found cracks on their aircraft with around 28,500 cycles and has had to ground three aircraft.


Qantas immediately took the plane out of rotation (which, to be fair, was easy as it was in maintenance anyway during this time), and has pledged to inspect the other 33 aircraft in their fleet with over 22,000 flights.

Qantas’ rival Virgin Australia, who also operates the Boeing 737 NG series, has claimed to media that they have already inspected their aircraft and found no cracks. Southwest rivals American Airlines and United have checked their fleets of Boeing 737 NG aircraft (they have 304 and 330 respectively) and not found any issues with the aircraft.

No cracks have been found on United’s 737 fleet. Photo: United Airlines.

What happens from here?

It seems that this issue is found with these aircraft before 30,000 flights and thus could happen at any time beyond 25,000 flights.

Boeing has issued a statement that any aircraft that has flown more than 22,500 cycles should be inspected for pickle fork cracks every 1,000 thereafter during normal maintenance. And you bet airlines are going to follow these instructions.

Boeing is continuing to inspect all Boeing 737 NG aircraft in the world with over 22,600 cycles. So far they had inspected all 800 with over 30,000 and have looked over approx one-third of all over 22,600.

“Depending on the results of these assessments, additional inspections or repairs may be required” – Boeing statement

What do you think? Is this problem widespread or just wear and tear? Let us know in the comments.