Operators of Airbus A380s with Engine Alliance GP7200 powerplants are being ordered to conduct an urgent inspection of the engines' fan hubs for damage.
The US FAA's emergency directive follows the uncontained failure of a GP7200 which, it says, had accumulated 3,527 cycles since new.
It describes the powerplant as a "relatively high cycle engine". The directive requires removal of the fan if damage or defects are found during the one-time visual inspection.
Investigators have been probing the uncontained GP7200 fan failure on an Air France A380 over Greenland on 30 September. The aircraft, bound for Los Angeles, diverted to Goose Bay in Canada.
The directive is intended to prevent failure of the fan hub, damage to the engine, and potential damage to the airframe.
Transportation Safety Board of Canada, in a preliminary bulletin, says the Air France A380 sustained "substantial damage" to the starboard outboard engine inlet during fan separation, and visible damage to slats and fairings either side of the powerplant.
Components have been located in Greenland while a runway inspection, says the bulletin, discovered debris on the arrival runway at Goose Bay.
Operators must conduct the engine inspection within two weeks if the fan hub has logged at least 3,500 cycles.
This deadline extends to five weeks for fans with 2,000-3,500 cycles, and eight weeks for all others.
It states that the inspections are an interim measure, because the cause of the fan failure has yet to be determined.