# AD 66-05-05: Compressor Rotor Disc - Type: Airworthiness directive - Status: Current - Products: Pratt & Whitney Division JT3D-1, JT3D-1-MC6 and JT3D-1-MC7 - Effective: February 18, 1966 - Superseded by: Nothing supersedes this AD - Product type: Engine - Amendment: 39-195 - Registered aircraft: 2 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/589019E92B20588D8625685B00603F73.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/66-05-05 ## The airworthiness directive 66-05-05 PRATT & WHITNEY: Amdt. 39-195 Part 39 Federal Register February 18, 1966. Applies to Models JT3D-1, JT3D-1-MC6, and JT3D-1-MC7 Turbofan Engines. Compliance required as indicated. To prevent failure of the second stage compressor rotor disc, accomplish the following: (a) Inspect second stage compressor rotor disc, P/N 421602, with less than 5,000 cycles on the effective date of this AD in accordance with (d) before the accumulation of 5,050 cycles and thereafter at intervals not to exceed 100 hours' time in service from the last inspection until the installation of rotor disc, P/N 405702, 457802, or 571202. (b) Inspect second stage compressor rotor disc, P/N 421602, with 5,000 or more cycles on the effective date of this AD that have been inspected using the fluorescent penetrant inspection procedures outlined in Pratt & Whitney Aircraft JT3D Overhaul Manual and the visual inspection procedures contained in Pratt & Whitney Aircraft letter dated June 15,1965, within the last 700 hours' time in service before the effective date of this AD in accordance with (d) before the accumulation of 750 hours' time in service since the fluorescent penetrant and visual inspection, and at intervals not to exceed 100 hours' time in service from the last inspection until the installation of rotor disc, P/N 405702, 457802, or 571202. (c) Inspect second stage compressor rotor disc, P/N 421602, with 5,000 or more cycles on the effective date of this AD that have not been inspected using the fluorescent penetrant inspection procedures outlined in Pratt & Whitney Aircraft JT3D Overhaul Manual and the visual inspection procedures contained in Pratt & Whitney Aircraft letter dated June 15, 1965, within the last 700 hours' time in service before the effective date of this AD in accordance with (d) within the next 50 hours' time in service after the effective date of this AD and thereafter at intervals not to exceed 100 hours' time in service from the last inspection until the installation of rotor disc, P/N 405702, 457802, or 571202. (d) Inspect for cracks front and rear sides of the inner portion of second stage compressor rotor disc web visible through the number one hub bore, using a strong light and a glass of at least three power or an FAA- approved equivalent inspection procedure. If any indication of a crack is found, remove the engine before further flight and disassemble for confirmation of the crack. If no cracks are found, the engine may be returned to service. Replace any cracked disc before further flight. (e) Remove from service second stage compressor rotor disc, P/N 421602, before the accumulation of 16,000 hours' time in service. (f) Remove from service second stage compressor rotor disc, P/N 571202 (which is a disc, P/N 421602, that has been modified by Pratt & Whitney Aircraft), before the accumulation of 16,000 hours' time in service as P/N 421602 and P/N 571202 combined. (g) For the purpose of this AD, the number of cycles equals the number of flights that involve an engine operating sequence consisting of engine starting, takeoff operation, landing, and engine shutdown. The number of cycles may be determined by actual count or, subject to acceptance by the assigned FAA maintenance inspector, may be calculated by dividing each second stage compressor rotor disc's hours' time in service by the operator's fleet average time per flight (involving an engine operating sequence, consisting of engine starting, takeoff operation, landing, and engine shutdown) for air planes equipped with Pratt & Whitney Model JT3D-1 Series turbofan engines. (h) Upon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Engineering and Manufacturing Branch, FAA Eastern Region, may adjust the repetitive inspection intervals specified in this AD to permit compliance at an established inspection period of the operator if the request contains substantiatingdata to justify the increase for that operator. (Pratt & Whitney Aircraft telegram to operators of JT3D-1, JT3D-1-MC6 and JT3D-1-MC7 turbofan engines dated December 10, 1965, pertains to this subject.) This directive effective February 18, 1966. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS 1E8](https://openairdocs.org/tcds/1E8): Pratt & Whitney Division; names 3 of 11 models: JT3D-1-MC6, JT3D-1-MC7, JT3D-1 ## Registered aircraft it may apply to (OpenAirDocs) Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment. - Aircraft: 2 (0 by airframe model, 2 by engine model) - Makers: Mcdonnell Douglas 2 Models with the most aircraft: - [Pratt & Whitney JT3D series](https://openairdocs.org/engine/pratt-whitney-jt3d-series): 2 aircraft (engine model) All 1 models: https://openairdocs.org/ad/66-05-05/models.md Every aircraft: https://openairdocs.org/ad/66-05-05/aircraft.md Its text cites no advisory circulars or STCs. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.