Some Boeing 737 NG planes have cracks in pickle forks. Image / Supplied
The pickle fork problem hitting operators of some Boeing 737s is growing around the world, although one airline flying the aircraft here says has rejected fresh calls to ground more planes.
Cracks on the alloy part which manages stress transferred from wings to the fuselage have been found in Indonesia's Lion Air, which reportedly found damage on 737 aircraft with fewer flights than the threshold for mandatory checks.
Qantas and Virgin Australia are the biggest operators of 737s in this region and fly them to New Zealand, but both say the new reports have no impact on the checks they have already done.
Lion Air found cracks on two 737s with fewer than 22,000 flights, leading the Australian Licensed Aircraft Engineers Association to call for all 737 NG aircraft to be inspected urgently, the Sydney Morning Herald reported today.
But Qantas doesn't operate the 737-900s - the model that Lion Air found cracks in. And it is restating its position that it has done more than what is required by regulators. Asked whether it would extend checks to all 75 of its 737s, a spokesman said it had responded to that last week.
Qantas has 33 of the affected NG (next generation) planes and found hairline cracks in three of them near one of eight bolts.
''We are awaiting parts from Boeing which we should have in the next few weeks. They should be all be repaired and back in the air by Christmas.''
The checks and repairs had no impact on its transtasman services and ''a minimal'' impact on domestic services in Australia.
All aircraft that flew the Tasman complied with the requirements of the safety regulators, the spokesman said.
Virgin Australia said it would follow any further directives issued by the Australian and US regulators ''as a matter of priority'' and would work with Boeing to continue the inspections within the required timeframes.
The airline has inspected all aircraft above 18,000 cycles, of which it has six. No issues were identified.
It has almost 80 737s in its fleet and said all would be inspected during routine heavy maintenance checks before they were due under the current directive.
Pickle forks in planes resemble in appearance and are named after the utensil used to pierce and handle pickled onions and gherkins.
The "pickle fork" was supposed to last the lifetime of the air frame (90,000 cycles - takeoffs and landing), but cracks were discovered in airplanes with less than 30,000 cycles.
Ryanair is the latest airline to find cracks on a small number of planes.
More than 50 cracks worldwide have been found in the aircraft, the workhorse of many airlines' fleets.
Air New Zealand used to fly 737s on domestic routes but by the end of 2015 these had been replaced by Airbus A320s.
The pickle fork problem is another blow for Boeing which is still dealing with the fallout from fatal crashes of its new model 737, the 737 MAX, which remains grounded.
''Boeing regrets the impact this issue is having on our 737NG customers worldwide and we are working around the clock to provide the support needed to return all airplanes to service as soon as possible.''