Cologne - The European Aviation Safety Agency has recently issued an emergency AD (Airworthiness Directive) briefing the users of a little group of Rolls Royce Trent 1000 engines to assure that no twin-engined airliner has both turbines from the troubled party.

The directive says that any airline which operates an airplane with two of the same class of turbines should set apart them to diminish the danger of a double in-flight shutdown. The Trent 1000 engines are mainly installed on the Boeing 787s and the AD addresses to 15 specific drivers. Previously this month, 11 787-9 of Air New Zealand was nailed down following two incidents involving Trent 1000s.

The company said the incidents were related to issues with intermediate pressure turbine blades on the first version of the engine. The EASA directive issued on December 21 also stated that after a shut down of a Trent 1000 turbine due to in-flight vibrations, an airline carrier (unnamed in the directive) returned to the departure airport. A post-flight elaborate engine examination uncovered that an intermediate pressure turbine blade was missing in the stem. Another detailed analysis uncovered that breaking away occurred as a result of corrosion.

Rolls Royce stated that the directive mandates actions that are taken by the company as part of the continual development of the active engine management program.