Airworthiness directives: CFM International,
[Federal Register: December 13, 1999 (Volume 64, Number 238)]
[Proposed Rules]
[Page 69428-69430]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr13de99-22]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 99-NE-57-AD]
RIN 2120-AA64
Airworthiness Directives; CFM International CFM56-2, -2A, 2B, -3, -3B, and -3C Series Turbofan Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
SUMMARY: This document proposes the adoption of a new airworthiness directive (AD) that is applicable to CFM International CFM56-2, -2A, - 2B, -3, -3B, and -3C series turbofan engines. This proposal would require a one-time eddy current inspection (ECI) for cracks in the bolt holes of high pressure turbine (HPT) front rotating air seals. This proposal 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 the proposed 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.
DATES: Comments must be received by January 12, 2000.
ADDRESSES: Submit comments to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 99-NE-57-AD, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may also be sent via the Internet using the following address: ``9-ane-adcomment@faa.gov''. Comments sent via the Internet must contain the docket number in the subject line. Comments may be inspected at this location between 8:00 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays.
The service information referenced in the proposed rule may be obtained from CFM International, Technical Publications Department, 1 Neumann Way, Cincinnati, OH 45215; telephone (513) 552-2800, fax (513) 552-2816. This information may be examined at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA.
FOR FURTHER INFORMATION CONTACT: James Rosa, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone (781) 238- 7152, fax (781) 238-7199.
SUPPLEMENTARY INFORMATION:
Comments Invited
Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications should identify the Rules Docket number and be submitted to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received.
Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filedin the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 99NE-57-AD.'' The postcard will be date stamped and returned to the commenter.
Availability of NPRMs
Any person may obtain a copy of this NPRM by submitting a request to the FAA, New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 99-NE-57-AD, 12 New England Executive Park, Burlington, MA 01803-5299.
Discussion
The Federal Aviation Administration (FAA) has received a report of an uncontained engine failure on a CFM International Model CFM56-3 turbofan engine. An investigation revealed a crack in a bolt hole of the high pressure turbine (HPT) front rotating air seal due to machining anomalies. The manufacturer has identified other HPT front rotating air seals by serial number (S/N) that may have the same anomalies. This condition, if not corrected, could result in cracks in the bolt holes of HPT front rotating air seals, which can lead to an uncontained engine failure and damage to the aircraft.
Service Information
The FAA has reviewed and approved the technical contents of the following CFM International Service Bulletins (SBs): CFM56-2 SB 72-869, dated November 12, 1999; CFM56-2A SB 72-470, dated November 12, 1999, CFM56-2B SB 72-611, dated November 12, 1999, and CFM56-3/3B/3C SB 72- 922, dated November 12, 1999. These SBs describe the procedures for eddy current inspections (ECI) for cracks in the bolt holes of HPT front rotating air seals caused by machining anomalies. Additionally, these SBs identify by S/N the HPT front rotating air seals that may have the same anomalies.
[[Page 69429]]
Proposed Actions
Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would require a one-time ECI for cracks in the bolt holes of HPT front rotating air seals. The compliance intervals are based upon risk analysis. The actions would be required to be accomplished in accordance with the SBs described previously.
Economic Analysis
There are approximately 121 engines of the affected design in the worldwide fleet. The FAA estimates that 13 engines installed on aircraft of US registry would be affected by this proposed AD, that it would take approximately 300 work hours per engine to accomplish the proposed actions, and that the average labor rate is $60 per work hour. Based on these figures, the total cost impact of the proposed AD on US operators is estimated to be $234,000.
Regulatory Impact
This proposal does not have federalism implications, as defined in Executive Order No. 13132, because it would not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. Accordingly, the FAA has not consulted with state authorities prior to publication of this proposal.
For the reasons discussed above, I certify that this proposed regulation (1) is not a ``significant regulatory action'' under Executive Order 12866; (2) is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Safety.
The Proposed Amendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:
PART 39--AIRWORTHINESS DIRECTIVES
-
The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
-
Section 39.13 is amended by adding the following new airworthiness directive:
CFM International: Docket No. 99-NE-57-AD.
Applicability: 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.
Compliance: Required as indicated, unless accomplished previously.
To prevent 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:
One-Time Eddy Current Inspections (ECI) Based Upon Engine Model and Thrust Ratings
(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:
CFM56-3 Series
(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 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.
Compliance Times for (a)(1), (a)(2), and (a)(3)
(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.
Compliance Times for (a)(5) and (a)(6)
(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
[[Page 69430]]
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.
Uninstalled Parts
(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.
CFM56-2 Series
(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.
Uninstalled Parts
(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.
CFM56-2A Series
(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.
Uninstalled Parts
(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.
CFM56-2B Series
(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.
Uninstalled Parts
(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.
Replace Cracked Parts
(16) Prior to further flight, replace cracked HPT front rotating air seals with serviceable parts.
Definition
(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.
Alternative Methods of Compliance
(c) 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 (ECO). Operators shall submit their request through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, ECO.
Note 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the ECO.
Ferry Flights
(d) 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 aircraft to a location where the inspection requirements of this AD can be accomplished.
Issued in Burlington, Massachusetts, on December 7, 1999. David A. Downey, Assistant Manager, Engine and Propeller Directorate, Aircraft Certification Service.
[FR Doc. 99-32194Filed12-10-99; 8:45 am]
BILLING CODE 4910-13-P
