Airworthiness Directives; Pratt & Whitney JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, -17AR, -209, -217, -217A, -217C, and -219 Turbofan Engines

The FAA is revising an existing airworthiness directive (AD) for Pratt & Whitney (PW) JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, -17AR, -209, -217, -217A, -217C, and -219 turbofan engines. That AD currently requires either replacing high pressure compressor (HPC) front hubs and HPC disks that have operated at any time with PWA 110-21 coating and that operated in certain engine models, or, visually inspecting and fluorescent penetrant inspecting (FMPI) for cracking of those parts and re-plating them if they pass inspection. This AD requires the same actions, but makes necessary corrections to inadvertent reference errors and omissions found in AD 2006-17-07, and relaxes some of the compliance times in Table 5. This AD results from our finding reference errors and omissions in AD 2006- 17-07, from determining that the AD as drafted imposed an unnecessary burden on operators if they have to immediately remove engines, and from requests to clarify compliance paragraphs. We are issuing this AD to prevent a rupture of an HPC front hub or an HPC disk that could result in an uncontained engine failure and damage to the airplane.