South Korea grounds 13 737NGs with 'pickle fork' cracks

South Korea is the latest country to ground a number of Boeing 737NG found to have structural cracks, following worldwide inspections of the popular narrowbody.

The Ministry of Land, Infrastructure and Transport (MOLIT) inspected 100 737NGs and found that 13 contain cracks. Nine of these were identified in a first round of inspection in October and had clocked more than 30,000 flight cycles.

Four more were discovered with cracks, after a second round of inspections was completed on 10 November. These aircraft recorded between 20,000 to 30,000 flight cycles, says MOLIT.

Upon discovering the cracks, MOLIT notified Boeing, which then sent a team to South Korea on 31 October to commence repair work. The affected aircraft will all be repaired by January 2020, and each aircraft takes about two weeks, the ministry adds.

MOLIT did not specify which airlines operated the affected 737NG aircraft. Cirium fleets data indicates that South Korean carriers operate 153 737NGs, the bulk of them 737-800s.

At the heart of the inspections is a piece of hardware known as a "pickle fork", which connects the wing to the aircraft fuselage. Cracking of the hardware could result in structural failure, which affects the structure integrity of the aircraft and results in loss of control.

Regulators had urged airlines operating 737NGs with more than 30,000 flight cycles to inspect their aircraft immediately for cracks. Aircraft that have logged 22,600-30,000 cycles should be inspected within the next 1,000 cycles.

South Korea’s MOLIT has also put in place further measures in response to the latest spate of cracking incidents.

For instance, carriers taking delivery of new 737NGs must check for cracks before registering the aircraft in South Korea.

737NGs that have passed inspections this time round will also be “thoroughly managed” by MOLIT’s aviation safety inspector and will be re-inspected within the next 3,500 flight cycles.

South Korea joins several other countries in the Asia-Pacific region to ground 737NGs over pickle fork cracks.

Australia’s Qantas has grounded three 737-800s found to have cracks, while Indonesia has also grounded three, two of them operated by Sriwijaya Air and the third by Garuda Indonesia.

Media reports also state that Lion Air found structural cracks on two 737NGs with less than 22,000 flight cycles. The Indonesian low-cost carrier has yet to respond to FlightGlobal’s request for comment.