Published on : Saturday, April 23, 2016
The January 29 incident triggered this reaction. The Ice shed from the blades caused the blades to rub the fan case causing the engines to vibration.
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.” FAA feels that the potential for common cause failure of both engines in flight is an urgent safety issue.
AD 2016-06-08 requires revising the airplane flight manual (AFM) to provide the flight crew a new fan ice removal procedure to reduce the likelihood of engine damage due to fan ice shedding. AD 2016-06-08 also requires, for certain airplanes, reworking the fan stator module assembly on GEnx-1B PIP2 engines. 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. We are issuing this AD to correct the unsafe condition on these products.”
The FAA has evaluated the safety risk associated with this condition and has determined that in the interest of safety it is necessary to mandate three actions:
FAA has also added that “recognizing the urgency of this safety issue, this AD represents a compressed schedule to rework a large number of airplanes located around the world. Both specialized tooling and trained personnel are required on-site to perform the rework at various maintenance facilities around the world. To complete the work, 29 airlines will need to reallocate 176 airplanes from revenue service to maintenance in order to conduct the (on-wing) rework. The FAA has determined that 150 days is the minimum time to rework one engine per airplane on the entire fleet.
Issuing an NPRM would require time to allow for public comment, and time for the FAA to consider and respond to those comments. As a result, the time allowed for the operators to perform the engine rework would be significantly reduced from 150 days, owing to the time that elapsed during the notice and comment period.
As a result, the considerable reduction in allowable compliance time would require operators to perform the rework significantly out of sequence with the maintenance schedule plan. In some cases, airplanes could be grounded. Thus, the reduced compliance time could substantially disrupt certain operators. The FAA considers that this is neither practicable nor in the public interest.
Boeing and GE have worked with the FAA on the plan and wish to fully resolve the issue. GE recommended corrective action to operators on April 1. The mandated work is already well under way, Boeing said, with more than 40 Dreamliner engine reworks completed, so far. The FAA airworthiness directive requires the airlines to perform GE’s recommendations within 150 days. Pilots flying 787 who haven’t gone rework have been ordered to undergo ice removal procedure.
When pilots touch 12,500 feet or above pilots are advised to rev each engine at 85% of full throttle every five minutes. FAA is known to make safety regulations and safety processes are often carried out for better functioning of aircrafts.