93-19-02 R1 PRATT & WHITNEY: Amendment 39-9038. Docket 92-ANE-33. Revises AD 93-19-02, Amendment 39-8695.
Applicability: Pratt & Whitney (PW) JT9D-3A, -7, -7H, -7A, -7AH, -7F, -7J, -20, and -20J turbofan engines installed on but not limited to Boeing 747 series, Airbus A300 series, and McDonnell Douglas DC-10 series aircraft.
Compliance: Required as indicated, unless accomplished previously.
To prevent diffuser case rupture and an uncontained engine failure, accomplish the following:
(a) For those diffuser cases that have not been inspected in accordance with PW Alert Service Bulletin (ASB) No. 6076, Revision 1, dated August 20, 1992, initially inspect the diffuser case for cracks in accordance with the intervals and requirements described in paragraphs (d), (f), (g), (i), (j), (k), or (l) of this AD, as applicable.
(b) For those diffuser cases that have not been inspected in accordance with PW ASB No. 6076, Revision 1, dated August 20, 1992, inspect the diffuser case rear rail along the shell wall at Boss 6 for weld repair size in accordance with PW ASB No. 6076, Revision 1, dated August 20, 1992, at the next M flange separation of the high pressure turbine case after the effective date of this AD. Diffuser cases with weld repairs in the rear rail along the shell wall of axial length greater than or equal to 1.5 inches at Boss 6 must not be returned to service. If the weld length is less than 1.5 inches, inspect in accordance with the new criteria, improved technique, intervals, and requirements defined in the Accomplishment Instructions of PW Service Bulletin (SB) No. 5591, Revision 7, dated August 25, 1992.
NOTE: Additional information regarding weld repair requirements for the diffuser case rear rail is contained in PW JT9D Engine Manual, Part Number 686028, dated September 1, 1993.
(c) For those diffuser cases that have been inspected in accordance with PW ASB No. 6076, Revision 1, dated August 20, 1992, accomplish the following:(1) For diffuser cases that have weld repairs in the rear rail along the shell wall at Boss 6 of axial length greater than or equal to 1.5 inches, remove from service and replace with a serviceable part prior to further flight.
(2) For diffuser cases that have weld repairs in the rear rail along the shell wall at Boss 6 of axial length less than 1.5 inches, initially inspect the diffuser case for cracks in accordance with the intervals and requirements described in paragraphs (d), (f), (g), (i), (j), (k), or (l) of this AD, as applicable.
(3) For diffuser cases that have no weld repairs in the rear rail along the shell wall at Boss 6, initially inspect the diffuser case for cracks in accordance with the intervals and requirements described in paragraphs (e), (g), (h), (i), (j), (k), or (l) of this AD, as applicable.
(d) For those diffuser cases that have been inspected in accordance with PW SB No. 5591, Revision 4, dated March 6, 1986, that contained rear rails with no cracks at any boss location at the last ECI, and have a weld repair in the rear rail along the shell wall at Boss 6, perform an initial ECI of the diffuser case rear rail for cracks in accordance with the new criteria and improved technique defined in the Accomplishment Instructions of PW SB No. 5591, Revision 7, dated August 25, 1992, as follows:
(1) For diffuser cases with greater than 275 cycles in service (CIS) since the last ECI performed in accordance with PW SB No. 5591, Revision 4, dated March 6, 1986, on the effective date of this AD, perform an ECI in accordance with the new criteria and improved technique defined in the Accomplishment Instructions PW SB No. 5591, Revision 7, dated August 25, 1992, prior to accumulating 500 CIS since the last ECI performed in accordance with PW SB No. 5591, Revision 4, dated March 6, 1986, or prior to accumulating 75 CIS after the effective date of this AD, whichever occurs first.
(2) For diffuser cases with less than or equal to 275 CISsince the last ECI performed in accordance with PW SB No. 5591, Revision 4, dated March 6, 1986, on the effective date of this AD, perform an ECI in accordance with the new criteria and improved technique defined in the Accomplishment Instructions of PW SB No. 5591, Revision 7, dated August 25, 1992, prior to accumulating 350 CIS since the last ECI performed in accordance with PW SB No. 5591, Revision 4, dated March 6, 1986.
(e) For those diffuser cases that have been inspected in accordance with PW SB No. 5591, Revision 4, dated March 6, 1986, that contained rear rails with no cracks at any boss location at the last ECI, and have no weld repairs in the rear rail along the shell wall at Boss 6, perform an ECI of the diffuser case rear rail for cracks in accordance with the new criteria and improved technique defined in the Accomplishment Instructions of PW SB No. 5591, Revision 7, dated August 25, 1992, prior to accumulating 500 CIS since the last ECI performed in accordance with PW SB No. 5591, Revision 4, dated March 6, 1986.
(f) For those diffuser cases that have been inspected in accordance with PW SB No. 5591, Revision 4, dated March 6, 1986, that contained rear rails with "A" cracks at Boss 6 at the last ECI, and have a weld repair in the rear rail along the shell wall at Boss 6, perform an ECI of the diffuser case rear rail for cracks in accordance with the new criteria and improved technique defined in the Accomplishment Instructions of PW SB No. 5591, Revision 7, dated August 25, 1992, prior to accumulating 300 CIS since the last ECI performed in accordance with PW SB No. 5591, Revision 4, dated March 6, 1986, or prior to accumulating 60 CIS after the effective date of this AD, whichever occurs first.
(g) For those diffuser cases that have been inspected in accordance with PW SB No. 5591, Revision 4, dated March 6, 1986, that contained rear rails with "A" cracks at any boss location other than at Boss 6 at the last ECI, with or without weld repairs in the rear rail along the shell wall at Boss 6, perform an ECI of the diffuser case rear rail for cracks in accordance with the new criteria and improved technique defined in the Accomplishment Instructions of PW SB No. 5591, Revision 7, dated August 25, 1992, prior to accumulating 300 CIS since the last ECI performed in accordance with PW SB No. 5591, Revision 4, dated March 16, 1986.
(h) For those diffuser cases that have been inspected in accordance with PW SB No. 5591, Revision 4, dated March 6, 1986, that contained rear rails with "A" cracks at Boss 6 at last ECI, and have no weld repairs at Boss 6, perform an ECI of the diffuser case rear rail for cracks in accordance with the new criteria and improved technique defined in the Accomplishment Instructions of PW SB No. 5591, Revision 7, dated August 25, 1992, prior to accumulating 300 CIS since the last ECI performed in accordance with PW SB No. 5591, Revision 4, dated March 6, 1986.
(i) For those diffuser cases that havebeen inspected in accordance with PW SB No. 5591, Revision 4, dated March 6, 1986, and contained rear rails with "B" cracks at Boss 6 at last ECI, with or without weld repairs in the rear rail along the shell wall at Boss 6, remove from service and replace with a serviceable part prior to accumulating 5 CIS after the effective date of this AD.
(j) For those diffuser cases that have been inspected in accordance with PW SB No. 5591, Revision 4, dated March 6, 1986, and contained rear rails with "B" cracks at any boss location other than Boss 6 at last ECI, with or without weld repairs in the rear rail along the shell wall at Boss 6, perform an ECI of the diffuser case rear rail for cracks in accordance with the new criteria and improved technique defined in the Accomplishment Instructions of PW SB No. 5591, Revision 7, dated August 25, 1992, prior to accumulating 75 CIS since the last ECI performed in accordance with PW SB No. 5591, Revision 4, dated March 6, 1986.
(k) For those diffuser cases that have been inspected in accordance PW SB No. 5591, Revision 4, dated March 6, 1986, and contained rear rails with "C" cracks at Boss 6 at last ECI, with or without weld repairs in the rear rail along the shell wall at Boss 6, remove from service and replace with a serviceable part prior to further flight.
(l) For those diffuser cases that have been inspected in accordance with PW SB No. 5591, Revision 4, dated March 6, 1986, and contain rear rails with "C" cracks at any boss location other than Boss 6 at last ECI, with or without weld repairs in the rear rail along the shell wall at Boss 6, remove from service and replace with a serviceable part as follows:
(1) For shell wall cracks of greater than or equal to 2 inches, remove from service and replace with a serviceable part prior to further flight.
(2) For shell wall cracks of less than 2 inches, remove from service and replace with a serviceable part within 5 CIS after the effective date of this AD.
(m)Thereafter, perform repetitive ECI of the diffuser case rear rail for cracks in accordance with the new criteria, improved technique, intervals, requirements, and removal from service criteria defined in the Accomplishment Instructions of PW SB No. 5591, Revision 7, dated August 25, 1992.
(n) For those diffuser cases that have been weld repaired at any boss location, at the next K flange separation of the diffuser case after the effective date of this AD, perform a one-time x-ray inspection of the diffuser case rear rail and sides of all bosses for weld quality in accordance with PW SB No. 6088, dated August 5, 1992, prior to installation of the diffuser case. Remove any weld defects within the inspection zone in accordance with PW SB No. 6088, dated August 5, 1992, prior to installation of the diffuser case.
(o) For those diffuser cases with rear rails that have been weld repaired at any boss location, incorporate the modifications described in PW SB No. 5805, Revision 6, dated September 15, 1993, at the next removal of the diffuser case for repair after the effective date of this AD.
(p) Installation of an improved diffuser case in accordance with PW SB No. 6105, Revision 2, dated May 14, 1993, constitutes terminating action to the inspections and modifications required by this AD.
(q) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Engine Certification Office. The request should be forwarded through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office.
NOTE: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Engine Certification Office.
(r) Except for diffuser cases that have cracks that require removal prior to further flight, special flight permits may beissued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished. For diffuser cases that have cracks that require removal prior to further flight, on aircraft that are eligible for an engine-inoperative ferry, special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished with one engine inoperative.
(s) The inspections and modifications shall be done in accordance with the following PW service bulletins:
Document No.
Pages
Revision
Date
SB No. 5591
1-3
7
August 25, 1992
4-9
6
August 14, 1992
10
7
August 25, 1992
11-12
6
August 14, 1992
13
7
August 25, 1992
14-15
6
August 14, 1992
16
7
August 25, 1992
17-19
6
August 14, 1992
Total pages: 19
SB No. 5805
1-4
6
September 15, 1993
5
Original
April 20, 1988
6-72
6
September 15, 1993
Total pages: 72
ASB No. 6076
1-5
1
August 20, 1992
6-19
Original
July 31, 1992
Total pages: 19
SB No. 6088
1-11
Original
August 5, 1992
Total pages: 11
SB No. 6105
1
2
May 14, 1993
2-7
Original
January 15, 1993
8
1
April 14, 1993
9
2
May 14, 1993
10-15
Original
January 15, 1993
16
2
May 14, 1993
17-18
Original
January 15, 1993
19
2
May 14, 1993
20-46
Original
January 15, 1993
47
1
April 14, 1993
48
2
May 14, 1993
49-56
Original
January 15, 1993
Total pages: 56.
This incorporation by reference was approved previously by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51 as of October 18, 1993 (58 FR 51212, October 1, 1993). Copies may be inspected at the FAA, New England Region, Office of the Assistant Chief Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.