Boeing warns of potential wing faults in some 737 – 600,700,800 and 900

(BBC) – Boeing has warned airlines about potential flaws on the wings of some 737 aircraft, including on the new-generation 737 Max that was grounded after two crashes.

The company has identified possible faulty parts on more than 300 aircraft worldwide. The parts, called wing slats, help reduce drag on take-off and landing.

Affected parts may be susceptible to premature failure or cracks, the US aviation regulator said.

Working with the Federal Aviation Administration, Boeing said it has reached out to airlines that fly 737 planes, advising them to inspect their slat track assemblies on Max and NG aircraft. The 737 NG series includes the 737-600, -700, -800 and -900 planes.

Leading edge slats are an aerodynamic control surface that extend from the front of the wing. Some the tracks may not meet manufacturing standards and may need to be replaced, Boeing and the FAA said. They said if the parts are found to be defective, airlines should replace them before returning the planes to service.

The faulty parts could fail prematurely or crack. The FAA said a part failure would not bring down a plane, but it could damage an aircraft while in flight.

Boeing has sent out a service bulletin and the FAA will issue an airworthiness directive requiring airlines to inspect and repair its slat track assemblies within 10 days.

The company discovered the problem Friday, when Boeing was meeting with the parts supplier. Boeing employees noticed some of the parts were not heat treated, which led them to believe there might be a safety issue.

News of the potentially faulty wing parts prompted a 1.6% fall in Boeing’s share price at the start of trading, but the stock partially recovered to finish 0.8% down.

Boeing is working on a software fix that will allow the Max to begin flying again, but differences have arisen between the US and Canada on how to train pilots on the software after the update.

Washington believes training on computers or tablets is sufficient for seasoned pilots, but Ottawa wants to require training on flight simulators.

Other regulators around the world are trying to work on a coordinated plan to get the Max back into the skies.