Qantas has grounded two more Boeing 737-800s found to have structural cracks, a day after it removed one aircraft that was found to have a similar issue from service.

Qantas has grounded two more Boeing 737-800s found to have structural cracks, a day after it removed one aircraft that was found to have a similar issue from service.

The carrier says in an update that it has completed preliminary inspections on 33 of its 737s which have higher flight cycles. Cirium fleets data shows that Qantas operates 75 737-800s.

At the heart of inspections is a structure known as a "pickle fork", which connects the wing to the fuselage of 737-800s. Cracking of the structure could result in failure, affecting the integrity of the aircraft and potentially resulting in loss of control.

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

Qantas says that the three grounded aircraft have flown around 27,000 flight cycles, but did not provide further details.

“Qantas is working with Civil Aviation Safety Authority and Boeing to resolve this issue, which involves some complex repair work. All three aircraft are expected to return to service before the end of the year,” the Oneworld carrier adds.

On 31 October, Qantas slammed what it called “alarmist” comments by its engineers’ union to ground the entire 737 fleet, saying it was "irresponsible and completely inconsistent with advice from regulators and the manufacturer".

Earlier last month, civil aviation authorities in Indonesia grounded three older 737NGs after inspections revealed similar structural cracks.