Airworthiness Directive · Amendment 39-11632 · CFM International CFM56-2, -2A, -2B, -3, -3B, and -3C Series Turbofan Engines
CFM International CFM56-2, -2A, -2B, -3, -3B, and -3C Series Turbofan Engines
CFM International (CFMI) CFM56-2, -2A, -2B, -3, -3B, and -3C series turbofan engines, installed on but not limited to McDonnell Douglas DC-8 series, Boeing 737 series, as well as Boeing E-3, E-6, and KC-135 (Military) series airplanes.
Note 1: This airworthiness directive (AD) applies to each engine identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For engines that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (c) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
This amendment adopts a new airworthiness directive (AD) that is applicable to CFM International CFM56-2, -2A, -2B, -3, -3B, and -3C series turbofan engines. This amendment requires a one-time eddy current inspection (ECI) for cracks in the bolt holes of high pressure turbine (HPT) front rotating air seals. This amendment is prompted by reports of machining anomalies in a bolt hole that led to an HPT front rotating air seal failure. The actions specified by this AD are intended to detect cracks in the bolt holes of HPT front rotating air seals, which can lead to an uncontained engine failure and damage to the aircraft.
To detect cracks in the bolt holes of high pressure turbine (HPT) front rotating air seals, which can lead to an uncontained engine failure and damage to the aircraft, accomplish the following:
(a) Perform a one-time ECI for cracks in the bolt holes of HPT front rotating air seals, part number 1282M72P03, and, if necessary, replace with serviceable parts, as follows:
(1) For CFM56-3-B1 engine nameplate models with HPT front rotating air seals listed by serial number (S/N) in paragraph 1.A(1), Effectivity, of CFMI CFM56-3/3B/3C Service Bulletin (SB) 72-922, dated November 12, 1999, inspect in accordance with the procedures described in Paragraph 2, Accomplishment Instructions, of that SB, and in accordance with the intervals listed in paragraph (a)(4)(i) or (a)(4)(ii) of this AD, as applicable.
(2) For CFM56-3B-2 models with maximum thrust limited to 20,100 or 18,500 pounds by the flight management computer (FMC) and aircraft flight manual (AFM), with HPT front rotating air seals listed by S/N in paragraph 1.A(1), Effectivity, of CFMI CFM56-3/3B/3C SB 72-922, dated November 12, 1999, inspect in accordance with the procedures described in Paragraph 2, Accomplishment Instructions, of that SB, and in accordance with the intervals listed in paragraph (a)(4)(i) or (a)(4)(ii) of this AD, as applicable.
(3) For CFM56-3C-1 models with maximum thrust limited to 20,100 or 18,500 pounds by the FMC and AFM, with HPT front rotating air seals listed by S/N in paragraph 1.A(1), Effectivity, of CFMI CFM56-3/3B/3C SB 72-922, dated November 12, 1999, inspect in accordance with the procedures described in Paragraph 2, Accomplishment Instructions, of that SB, and in accordance with the intervals listed in paragraph (a)(4)(i) or (a)(4)(ii), as applicable.
(4) Use the following compliance times for the engine models listed in paragraphs (a)(1), (a)(2), and (a)(3) of this AD:
(i) For HPT front rotating air seals with less than 10,000 cycles since new (CSN) on the effective date of this AD, inspect at the next engine shop visit after accumulating 4,000 CSN, not to exceed 13,000 CSN.
(ii) For HPT front rotating air seals with 10,000 CSN or more on the effective date of this AD, inspect at the next engine shop visit prior to accumulating 3,000 cycles-in-service (CIS) after the effective date of this AD, or prior to accumulating 20,000 CSN, whichever occurs first.
(5) For CFM56-3B-2 engine nameplate models, with HPT front rotating air seals listed by S/N in paragraph 1.A(1), Effectivity, of CFMI CFM56-3/3B/3C SB 72-922, dated November 12, 1999, inspect in accordance with the procedures described in Paragraph 2, Accomplishment Instructions, of that SB, and in accordance with the intervals listed in paragraphs (a)(7)(i), or (a)(7)(ii) of this AD, as applicable.
(6) For CFM56-3C-1 models with maximum thrust limited to 22,100 pounds by the FMC and AFM, with HPT front rotating air seals listed by S/N in paragraph 1.A(1), Effectivity, of CFMI CFM56-3/3B/3C SB 72-922, dated November 12, 1999, inspect in accordance with the procedures described in Paragraph 2, Accomplishment Instructions, of that SB, and in accordance with the intervals listed in paragraphs (a)(7)(i), or (a)(7)(ii) of this AD, as applicable.
(7) Use the following compliance times for the engine models listed in paragraphs (a)(5) and (a)(6) of this AD:
(i) For HPT front rotating air seals with less than 9,800 CSN on the effective date of this AD, inspect at the next engine shop visit after accumulating 4,000 CSN, not to exceed 12,800 CSN.
(ii) For HPT front rotating air seals with 9,800 CSN or more on the effective date of this AD, inspect at the next engine shop visit prior to accumulating 3,000 CIS after the effective date of this AD, or prior to accumulating 15,800 CSN, whichever occurs first.
(8) For CFM56-3C-1 engine nameplate models, with HPT front rotating air seals listed by S/N in paragraph 1.A(1), Effectivity, of CFMI CFM56-3/3B/3C SB 72-922, dated November 12, 1999, inspect in accordance with the procedures described in Paragraph 2, Accomplishment Instructions, of that SB, as follows:
(i) For HPT front rotating air seals with less than 9,100 CSN on the effective date of this AD, inspect at the next engine shop visit after accumulating 4,000 CSN, not to exceed 12,100 CSN.
(ii) For HPT front rotating air seals with 9,100 CSN or more on the effective date of this AD, inspect at the next engine shop visit prior to accumulating 3,000 CIS after the effective date of this AD, or prior to accumulating 15,100 CSN, whichever occurs first.
(9) Prior to installation in CFM56-3/3B/3C series engines, inspect uninstalled parts listed by S/N in paragraph 1.A(1), Effectivity, of CFMI CFM56-3/3B/3C SB 72-922, dated November 12, 1999, in accordance with Paragraph 2, Accomplishment Instructions, of that SB.
(10) For CFM56-2 engine nameplate models, with HPT front rotating air seals listed by S/N in paragraph 1.A(1), Effectivity, of CFMI CFM56-2 SB 72-869, dated November 12, 1999, inspect in accordance with the procedures described in Paragraph 2, Accomplishment Instructions, of that SB, as follows:
(i) For HPT front rotating air seals with less than 9,100 CSN on the effective date of this AD, inspect at the next engine shop visit after accumulating 4,000 CSN, not to exceed 10,100 CSN.
(ii) For HPT front rotating air seals with 9,100 CSN or more on the effective date of this AD, inspect at the next engine shop visit prior to accumulating 1,000 CIS after the effective date of this AD, or prior to accumulating 13,100 CSN, whichever occurs first.
(11) Prior to installation in CFM56-2 series engines, inspect uninstalled parts listed by S/N in paragraph 1.A(1), Effectivity, of CFMI CFM56-2 SB 72-869, dated November 12, 1999, in accordance with Paragraph 2, Accomplishment Instructions, of that SB.
(12) For CFM56-2A engine nameplate models, with HPT front rotating air seals listed by S/N in paragraph 1.A(1), Effectivity, of CFM56-2A SB 72-470, dated November 12, 1999, inspect in accordance with the procedures described in Paragraph 2, Accomplishment Instructions, of that SB, after accumulating 3,000 CSN but before accumulating 6,000 CSN.
(13) Prior to installation in CFM56-2A series engines, inspect uninstalled parts listed by S/N in paragraph 1.A(1), Effectivity, of CFMI CFM56-2A SB 72-470, dated November 12, 1999, in accordance with the procedures described in Paragraph 2, Accomplishment Instructions, of that SB.
(14) For CFM56-2B engine nameplate models, with HPT front rotating air seals listed by S/N in paragraph 1.A(1), Effectivity, of CFM56-2B SB 72-611, dated November 12, 1999, inspect in accordance with the procedures described in Paragraph 2, Accomplishment Instructions, of that SB, after accumulating 3,000 CSN but before accumulating 6,000 CSN.
(15) Prior to installation in CFM56-2B series engines, inspect uninstalled parts listed by S/N in paragraph 1.A(1), Effectivity, of CFMI CFM56-2B SB 72-611, dated November 12, 1999, in accordance with the procedures described in Paragraph 2, Accomplishment Instructions, of that SB.
(16) Prior to further flight, replace cracked HPT front rotating air seals with serviceable parts.
(b) For the purpose of this AD, an engine shop visit is defined as the next time, after the effective date of this AD, an engine is in the shop for the purpose of maintenance or inspection.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
