AD NUMBER: 2012-02-07

PRODUCT: General Electric Company (GE) CF6-45 and CF6-50 series turbofan engines with certain low-pressure turbine (LPT) rotor stage 3 disks installed.
SUBJECT: Airworthiness Directive 2012-02-07
ACTION: Final rule.

SUMMARY: The FAA is superseding two existing airworthiness directives (ADs) for General Electric Company (GE) CF6-45 and CF6-50 series turbofan engines with certain low-pressure turbine (LPT) rotor stage 3 disks installed.

The existing ADs currently require inspections of high-pressure turbine (HPT) and LPT rotors, engine checks, and vibration surveys. This new AD retains the requirements of the two ADs being superseded, adds an optional LPT rotor stage 3 disk removal after a failed HPT blade borescope inspection (BSI) or a failed engine core vibration survey, establishes a new lower life limit for the affected LPT rotor stage 3 disks, and requires removing these disks from service at times determined by a drawdown plan.

This AD was prompted by the determination that a new lower  life limit for the LPT rotor stage 3 disks is necessary. The FAA is issuing this AD to prevent critical lifelimited rotating engine part failure, which could result in an uncontained engine failure and damage to the airplane.

DATES: This AD is effective March 6, 2012.

FMI: AD