Boeing has discovered 38 of its aircraft with 'pickle fork' cracks, having inspected 810 of the company’s 737 NG jets. The planes will now be grounded until the structural cracks are repaired, and replacement parts are received by the company.

Pickle fork

The pickle fork refers to the part of the aircraft that attaches the main fuselage of the plane to its wing structure, playing a key role in maintaining and managing the force of the aircraft.

Urgent inspections of the Boeing aircraft had been ordered by the US government when Indonesia’s Sriwijaya Air was forced to ground two planes. US regulators initially called for 165 of the older 737 Ngs to be inspected, but many more have gone under the microscope as the issue widens.

Aircraft that have been active for over 30,000 flights are being examined currently, but the authorities want this to be extended to a much larger group of the aircraft in the coming months.

In an official comment on the problem, the FAA told Reuters that “a small number of aircraft based in the United States have been removed from service while Boeing develops instructions for customers to repair or replace the affected parts.”

Boeing 737, Pickle Fork Cracks, Southwest Airlines
The cracks were detected on two of Southwest's Boeing 737 aircraft. Photo: Southwest Airlines

FAA announcement

The FAA further announced that “is working with the manufacturer and other international aviation safety regulators to better understand the factors that led to the formation of the cracks.”

Southwest Airlines confirmed that it has grounded two aircraft and that it intends to update the public at some point next week. “We do not have a timeline for when the airplanes will be returned to service, we are working with Boeing to schedule the upcoming repairs,” spokesperson Brandy King commented.

Brazilian carrier Gol has also grounded 11 planes as investigations continue. A spokesman for the company revealed that the issue would impact on approximately 3% of its customers between now and December 15.

737 NG pickle forks
GOL will be adding more 737 MAX aircraft to its fleet. Photo: Boeing

The NG version of the 737 has been in production since the 1990s. Boeing is steadily replacing this aircraft with the updated 737 MAX, but this model has been grounded since March following two fatal crashes. Boeing has stated, though, that the aircraft should be operational again in January.

Technical experts at Boeing are currently examining the affected aircraft, with repairs expected to take several weeks.

Pressure and force

While it is not known precisely why the Boeing 737 aircraft have developed cracks in their pickle forks, it is understood that the excessive pressure and force that airliners experience can cause metal fatigue. It is therefore not unusual for regulators to order inspections on particular aspects of an aircraft.

Boeing has endured a difficult year commercially following the grounding of its 737 MAX aircraft. Sales of aircraft from European rival Airbus have far outstripped Boeing's performance, and this latest pickle fork issue will be extremely unwelcome at a challenging time for the legendary aircraft manufacturer.