AD 70-11-03

70-11-03 PRATT & WHITNEY: Amdt. 39-993. Pratt & Whitney Aircraft JT8D series turbofan engines. Applies to Pratt & Whitney JT8D series turbofan engines, incorporating sixth stage compressor discs P/N 586906 (wide rim) which have encountered previous sixth stage blade failures and were not subsequently reworked in accordance with P&WA Service telegram SE:RWJ: 9-6-24-1 dated 24 June 1969.

Compliance required as indicated.

To preclude sixth stage compressor rotor disc failures as the result of disc rim front face galling caused by blade retention tangs, accomplish the following:

a. For engines incorporating any of the previously listed sixth stage compressor rotor disc:

1. With 1200 hours or more in service since a 6th stage compressor blade failure, within the next 600 hours in service after the effective date of this AD replace the suspect sixth stage compressor disc with a new, used or a disc reworked in a manner approved by Chief, Engineering and ManufacturingBranch, Eastern Region, New York.

2. With 1200 hours or less in service since a 6th stage compressor blade failure, prior to accumulation of 1800 hours time in service since 6th stage blade failure replace the suspect sixth stage compressor disc with a new, used or disc reworked in a manner approved by Chief, Engineering Branch, Eastern Region, New York.

b. For the purposes of this AD a blade failure is defined as one in which any portion of the blade root is separated from the blade.

c. Upon submission of substantiating data by an owner or operator through an FAA Maintenance Inspector, the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration, Eastern Region, may adjust the compliance time.

This amendment is effective June 12, 1970.