AD FAA-2013-0447

We are superseding emergency airworthiness directive (AD) 2013-14-51 for General Electric Company (GE) GE90-110B1 and GE90-115B turbofan engines with affected transfer gearbox assembly (TGB) radial gearshafts installed. AD 2013-14-51 was sent previously to all known U.S. owners and operators of GE90-110B1 and GE90-115B turbofan engines. AD 2013-14-51 prohibited operation of an airplane if more than one installed engine has an affected TGB radial gearshaft. This AD contains the same prohibition as AD 2013-14-51 and also prohibits operation of any airplane 60 days after the effective date of this new AD if any installed engine has an affected TGB radial gearshaft. This new AD also revises the applicability by adding GE90- 76B, GE90-77B, GE90-85B, GE90-90B, GE90-94B, and GE90-113B turbofan engine models and adds a mandatory terminating action. This new AD was prompted by reports of three failures of TGB radial gearshafts which resulted in in-flight shutdowns (IFSDs). We are issuing this new AD to prevent failure of the TGB radial gearshaft, which could result in IFSD of one or more engines, loss of thrust control, and damage to the airplane.