AD 73-23-05

73-23-05 GENERAL ELECTRIC: Amdt. 39-1742 as amended by Amendment 39-1775. Applies to Models CJ610-1, -4, -5, -6 and J85-GE-17B turbojet and CF700-2C turbofan engines.

Compliance required as indicated.

1. Inspect first stage turbine discs, P/N 634E583P4 and P/N 634E583P4Y, (Wheel Assembly P/N 841B690P6) for cracks and a minimum radius of .015 inch in the forward rabbet radius and for cracks and a minimum radius of .020 inch in the aft rabbet radius in accordance with the following schedule. Use the procedures outlined in General Electric Alert Service Bulletin No. (CJ610) A72-70, or (CF700) A72-70, or later FAA approved revision or equivalent inspection method approved by the Chief, Engineering and Manufacturing Branch, New England Region, Federal Aviation Administration.

a. Inspect turbine discs with 2300 or more total cycles on the effective date of this AD as follows:

(1) Within next 10 cycles if not previously inspected in accordance with G.E. Alert Service Bulletins No. A72-70, or later FAA approved revisions.

(2) Prior to accumulation of 800 cycles since last inspection if previously inspected in accordance with G.E. Alert Service Bulletins No. A72-70, or later FAA approved revisions. Discs in excess of both 2300 total cycles, and 800 cycles since last inspection must be inspected within the next 50 cycles.

b. Inspect turbine discs with less than 2300 total cycles on the effective date of this AD, in accordance with G.E. Alert Service Bulletin No. (CJ610) A72-70 or (CF700) A72-70, or later FAA approved revisions prior to the accumulation of 2310 cycles or every 800 cycles since last inspection, whichever comes later, it discs have been previously inspected in accordance with G.E. Alert Service Bulletin A72-70.

2. Remove from service all first stage turbine discs in accordance with the following schedule.

a. Remove turbine discs with 3090 or less total cycles on the effective date of this AD, from service priorto the accumulation of 3100 cycles.

b. Remove turbine discs with more than 3090 total cycles on the effective date of the AD, from service prior to the accumulation of 10 additional cycles.

3. Inspect second stage turbine discs, P/N 646C596P1, for cracks and a minimum radius of .020 inch in the forward rabbet radius in accordance with the following schedule. Use the procedures outlined in General Electric Alert Service Bulletin No. (CJ610) A72-80, or (CF700) A72-80, or later FAA approved revision or equivalent inspection method approved by the Chief, Engineering and Manufacturing Branch, New England Region, Federal Aviation Administration.

a. Inspect turbine discs with 2800 or more cycles on the effective date of this AD, in accordance with General Electric Alert Service Bulletin No. (CJ610) A72-80, or (CF700) A72-80, or later FAA approved revisions within the next 10 cycles.

b. Inspect turbine discs with 2201 or more cycles on the effective date of this AD, inaccordance with General Electric Alert Service Bulletin No. (CJ610) A72-80, or (CF700) A72-80, or later FAA approved revisions within the next 100 cycles or at 2810 cycles whichever occurs first.

c. Inspect turbine discs with 2200 or less cycles on the effective date of this AD, in accordance with General Electric Alert Service Bulletin No. (CJ610) A72-80, or (CF700) A72-80, or later FAA approved revisions at first overhaul or at 2300 cycles whichever occurs first.

4. For the purposes of this AD, a cycle is defined as that set forth in the subject Alert Service Bulletins.

5. Discs with less than the specified radius or which exhibit the specified point-type flourescent indications or cracks are to be replaced with like parts which meet the specified minima for radii and criteria for size and location of point-type flourescent indications and cracks.

This supersedes Amendment 39-855 (34 F.R. 15467), AD 69-20-08.

Amendment 39-1742 became effective November 20,1973.

This Amendment 39-1775 becomes effective upon publication in the Federal Register.