The US Federal Aviation Administration has issued an urgent safety directive over the latest General Electric Co engines fitted on Boeing Co's 787 Dreamliner jets.
The directive follows the failure of a GEnx-1B PIP2 engine, part of a family of engines plagued by issues related to icing. In the incident, which occurred on 29 January, ice on the fan of engine blades of a Dreamliner jet broke loose.
Airlines operating the jets have been directed to either repair them or swap out at least one with an older model.
"Ice shed from the fan blades ... causing the blades to rub against the fan case, resulting in engine vibration," GE Aviation spokesman Rick Kennedy told CNN.
According to the FAA document, "Susceptibility to heavy fan blade rubs, if not corrected, could result in engine damage and a possible in-flight non-restartable power loss of one or both engines."
''The potential for common cause failure of both engines in flight is an urgent safety issue,'' the FAA said in its order.
The high-efficiency GEnx engine developed for wide-body aircraft, had faced issues with icing earlier.
In 2013, airlines were ordered by the authority to avoid flying 787 and 747-8 planes equipped with the GE engines near thunderstorms in high-altitude cruise flight.
According to the FAA, even in those sub-freezing temperatures, moisture from the storms could enter the engines and form dangerous ice.
The latest issue was not related to the 2013 situation. The incident which occurred at 20,000 feet altitude, was lower than previous icing issues that had been seen with the engine model.
Meanwhile, Boeing and GE had conducted a joint investigation into the issue and along with the FAA had worked out a plan to fully resolve it, Boeing said Friday.
According to Boeing, the mandated work was already well under way, with over 40 Dreamliner engine reworks completed, so far. Under the FAA's airworthiness directive airlines are required to carry out GE's recommendations within 150 days.
For pilots flying 787s that had not yet undergone the rework, the FAA had ordered an in-flight ice removal procedure.
In case of suspected ice buildup above 12,500 feet, or when the indicator light confirmed it, pilots had been advised to rev each engine at 85 per cent of full throttle every five minutes.