AD 78-16-05

78-16-05 PRATT & WHITNEY AIRCRAFT: Amendment 39-3274. Applies to all Pratt & Whitney Aircraft JT9D turbofan engines not incorporating an annular strainer element, in accordance with Pratt & Whitney Service Bulletin 4860 dated March 16, 1978, or later FAA approved revision, in the No. 4 bearing compartment.

Compliance is required as indicated.

To preclude failures of sixth stage turbine disks due to a plugged No. 4 bearing compartment oil scavenge tube, inspect the inside of the No. 4 bearing compartment sump for coke in accordance with the provisions of Pratt & Whitney Alert Service Bulletin No. 4826, dated October 17, 1977, or later FAA approved revision, in accordance with the following schedule:

Engines with No. 4 bearing compartments having more than 6000 hours time in service since new or the last cleaning per ASB 4826:

1. Must have a daily visual tailpipe check for oil leakage from the No. 4 bearing compartment. If leakage is noted, the compartment must be inspected prior to further flight. The daily visual check may be discontinued after accomplishing the compartment inspection noted below. A flight crewmember may perform the daily check.

NOTE: For the purpose of this AD, compliance with the daily visual check may be shown by recording accomplishment in accordance with FAR 121.380 or by amending the manual required by FAR 121.133 to include the check.

2. Must have the compartment inspected within the next 1500 hours time in service after the effective date of this AD, unless already accomplished, and every 5000 hours time in service thereafter.

Engines having unacceptable coke formation in the forward portion of the No. 4 compartment sump area, as defined in Figure 2 of ASB 4826, must have the sump and compartment oil scavenge tube cleaned in accordance with the JT9D Engine Manual, P/N 646028, Section 72-53-00, prior to further flight.

Upon request of the operator, an equivalent method of compliance with the requirements of this AD may be approved by the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration, New England Region.

Upon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Engineering and Manufacturing Branch, New England Region, may adjust the initial inspection interval specified in this AD to permit compliance at an established inspection period of the operator if the request contains substantiating data to justify the increase for that operator.

The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by this directive, who have not already received these documents from the manufacturer, may obtain copies upon request to Pratt & Whitney Aircraft, Division of United Technologies Corporation, 400 Main Street, East Hartford, Connecticut 06108. These documents may also be examined at the Federal Aviation Administration, New England Region, 12 New England Executive Park, Burlington, Massachusetts, and at FAA Headquarters, 800 Independence Avenue, S.W., Washington, D.C. A historical file on this AD, which includes the incorporated material in full, is maintained by the FAA at its Headquarters in Washington, D.C., and at FAA, New England Region Headquarters, Burlington, Massachusetts.

This amendment becomes effective September 12, 1978.