AD 2021-18-13 Requires A Borescope Inspection (BSI) Or Visual Inspection Of The Combustion Outer Liner Shell

The FAA is adopting a new airworthiness directive (AD) for all General Electric Company (GE) CF34-8 model turbofan engines with a certain outer shell combustion liner (combustion outer liner shell) installed.

This AD was prompted by two in-flight engine shutdowns (IFSDs) that occurred as a result of failures of the combustion outer liner shell. This AD requires a borescope inspection (BSI) or visual inspection of the combustion outer liner shell and, depending on the results of the inspection, possible replacement of the combustion outer liner shell. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective October 22, 2021.

Supplementary Information: The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to all CF34-8C1, CF34-8C5, CF34-8C5A1, CF34-8C5B1, CF34-8C5A2, CF34-8C5A3, CF34-8E2, CF34-8E2A1, CF34-8E5, CF34-8E5A1, CF34-8E5A2, CF34-8E6, and CF34-8E6A1 model turbofan engines with a certain combustion outer liner shell installed. The NPRM published in the Federal Register on January 10, 2020 (85 FR 1292). The NPRM was prompted by reports of two IFSDs on GE CF34-8C and -8E model turbofan engines. These IFSDs were due to the cracking and collapsing of the combustion outer liner shell, which resulted in thermal distress of the high-pressure turbine and low-pressure turbine (LPT) including burn-through of the LPT case. In the NPRM, the FAA proposed to require a BSI or visual inspection of the combustion outer liner shell and, depending on the results of the inspection, possible replacement of the combustion outer liner shell. The FAA is issuing this AD to address the unsafe condition on these products.

FMI: www.regulations.gov