WASHINGTON • US aviation giant Boeing has ordered airlines around the world to address a "fragility" problem, after a landing gear panel broke off from a passenger jet following take-off, and fell in a Shanghai suburb.

The sheet of metal, weighing 60kg, plunged 3,700m to the ground shortly after Air France Flight 111 took off from Shanghai and headed for Paris last Monday, Boeing said last Saturday.

No one was injured in the Boeing 777 incident, which saw the panel smash into the roof of a factory.

The triangular metal part was marked "Made in Canada" and serial numbers were printed on it, the Shanghai Morning Post reported last week.

Boeing spokesman Chris Villiers said: "We've been working real closely with our customers and have provided guidance on how to make any maintenance required.

"It does not affect the structural integrity of the landing gear nor the safety of the flight."

He said that Boeing was treating the incident "with utmost concern and urgency".

The panel, which Mr Villiers stressed was not part of the landing gear structure itself, is one of the parts that open and close as the landing gear deploys.

The problem has to do with the fasteners that hold the panel in place.

Boeing has issued a service bulletin to the fleet, providing instructions on how to resolve the issue, Agence France-Presse reported yesterday.

In a statement, Boeing said: "We have implemented the change for airplanes produced in our factories."

More than 1,100 Boeing 777 aircraft are in service with dozens of airlines around the world.

Air France and Boeing both acknowledged that they had been aware for some time of the "fragility" of the metal attached to the plane's landing gear known as the "drag strut door", Hong Kong's Sunday Morning Post reported.

Air France said that the loss of the panel did not affect the aircraft's airworthiness, adding: "The flight continued to Paris without incident."

Air France has launched an inspection of 66 Boeing 777 jets delivered between 1998 and 2008, the Sunday Morning Post said.

The airline's spokesman Cecile Baudin-Hardin said: "Other airlines have also experienced problems with the fragility of this part."

The Sunday Morning Post cited aviation expert David Learmount of Flight Global as saying: "Air France is aware of it, Boeing is aware of it. Boeing is probably looking for some kind of fix, then it looks at it and says a fix will be so costly, we'll have to charge the fix to the airlines as well.

"Actually, having the odd failure - since the failures are so few - does that justify the expense of making a modification which itself might have its problems?"