AD 2017-23-09

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc., Model CL-600-2A12 (CL-601 Variant) and CL-600-2B16 (CL-601-3A, CL-601-3R, and CL-604 Variants) airplanes. This AD was prompted by a determination that the bushing holes on the engine mount rib might not conform to the engineering drawings and that certain inspections of the engine mount rib must be included in the airworthiness limitations section (ALS) of the Instructions for Continued Airworthiness (ICA). This AD requires revising the maintenance or inspection program to incorporate certain airworthiness limitation items (ALIs). We are issuing this AD to address the unsafe condition on these products.

Final rule.

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0 1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

Sec. 39.13 [Amended]

0 2. The FAA amends Sec. 39.13 by adding the following new airworthiness directive (AD):

2017-23-09 Bombardier, Inc.: Amendment 39-19103; Docket No. FAA- 2017-0338; Product Identifier 2016-NM-153-AD.

(a) Effective Date

This AD is effective December 26, 2017.

(b) Affected ADs

None.

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(c) Applicability

This AD applies to the Bombardier, Inc., airplanes identified in paragraphs (c)(1), (c)(2), and (c)(3) of this AD, certificated in any category.
(1) Bombardier, Inc., Model CL-600-2A12 (CL-601) airplanes, having serial numbers (S/Ns) 3001 through 3066 inclusive.
(2) Bombardier, Inc., Model CL-600-2B16 (CL-601-3A and CL-601-3R Variants) airplanes, having S/Ns 5001 through 5194 inclusive.
(3) Bombardier, Inc., Model CL-600-2B16 (CL-604 Variant) airplanes having S/Ns 5301 through 5665 inclusive, and S/Ns 5701 through 5990 inclusive.

(d) Subject

Air Transport Association (ATA) of America Code 05, Periodic inspections.

(e) Reason

This AD was prompted by a determination that the bushing holes on the engine mount rib may not conform to the engineering drawings and that certain inspections of the engine mount rib must be included in the airworthiness limitations section (ALS) of the Instructions for Continued Airworthiness (ICA). We are issuing this AD to detect and correct failure of an engine mount rib. Failure of an engine mount rib could compromise the structural integrity of the engine mount and could lead to subsequent detachment of an engine.

(f) Compliance

Comply with this AD within the compliance times specified, unless already done.(g) Maintenance or Inspection Program Revision

Within 60 days after the effective date of this AD: Revise the maintenance or inspection program, as applicable, to incorporate inspections for fatigue cracking of the engine mount rib and corrective actions, as applicable, in accordance with a method approved by the Manager, New York ACO Branch, FAA.
Note 1 to paragraph (g) of this AD: Guidance can be found in Tasks 54-10-00-106 and 54-50-00-103 of Chapter 5 of the Bombardier Time Limits/Maintenance Checks (TLMC) Manual PSP 601-5 (for Model CL-600-2A12 (CL-601 Variant) airplanes); Bombardier TLMC Manual PSP 601A-5 (for CL-600-2B16 (CL-601-3A and CL-601-3R Variants) airplanes); Bombardier TLMC Manual CL-604 (for Model CL-600-2B16 (CL-604 Variant) airplanes, S/Ns 5301 through 5665 inclusive); and Bombardier TLMC Manual CL-605 (for Model CL-600-2B16 (CL-604 Variant) airplanes, S/Ns 5701 through 5990).

(h) No Alternative Actions and/or Intervals

After the maintenance orinspection program has been revised as required by paragraph (g) of this AD, no alternative actions (e.g., inspections) and/or intervals may be used, unless the actions and/or intervals are approved as an AMOC in accordance with the procedures specified in paragraph (i)(1) of this AD.

(i) Other FAA AD Provisions

The following provisions also apply to this AD:
(1) Alternative Methods of Compliance (AMOCs): The Manager, New York ACO Branch, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the certification office, send it to ATTN: Program Manager, Continuing Operational Safety, FAA, New York ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7300; fax 516-794-5531. Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office.
(2) Contacting the Manufacturer: For any requirement in this AD to obtain corrective actions from a manufacturer, the action must be accomplished using a method approved by the Manager, New York ACO Branch, FAA; or Transport Canada Civil Aviation (TCCA); or Bombardier, Inc.'s TCCA Design Approval Organization (DAO). If approved by the DAO, the approval must include the DAO-authorized signature.

(j) Related Information

(1) Refer to Mandatory Continuing Airworthiness Information (MCAI) Canadian Airworthiness Directive CF-2015-09R1, dated June 29, 2015, for related information. This MCAI may be found in the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2017-0338.
(2) For more information about this AD, contact Aziz Ahmed, Aerospace Engineer, Airframe and Mechanical Systems Section, New York Aircraft ACO Branch, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7329; fax 516-794-5531.

(k) Material Incorporated by Reference

None.

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain Bombardier, Inc., Model CL-600-2A12 (CL-601 Variant) and CL-600-2B16 (CL-601-3A, CL-601- 3R, and CL-604 Variants) airplanes. The NPRM published in the Federal Register on June 14, 2017 (82 FR 27219) (``the NPRM''). The NPRM was prompted by a determination that the bushing holes on the engine mount rib might not conform to the engineering drawings and that certain inspections of the engine mount rib must be included in the ALS of the ICA. The NPRM proposed to require revising the maintenance or inspection program to incorporate certain ALIs. We are issuing this AD to detect and correct failure of an engine mount rib. Failure of an engine mount rib could compromise the structural integrity of the engine mount and could lead to subsequent detachment of an engine.
Transport Canada Civil Aviation (TCCA), which is the aviation authority for Canada, has issued Canadian Airworthiness Directive CF- 2015-09R1, dated June 29, 2015 (referred to after this as the Mandatory Continuing Airworthiness Information, or ``the MCAI''), to correct an unsafe condition for certain Bombardier, Inc., Model CL-600-2A12 (CL- 601 Variant) and CL-600-2B16 (CL-601-3A, CL-601-3R, and CL-604 Variants) airplanes. The MCAI states:

The aeroplane manufacturer has determined that the bushing holes on the engine mount rib may not conform to the engineering drawings. Non-conforming bushing holes could increase loading on adjacent fasteners, resulting in premature fatigue cracking of the engine mount rib.
In addition, it was also discovered that the inspection requirements for the engine mount rib were not listed in the Airworthiness Limitations Section of the Instructions for Continued Airworthiness.
Failure of the engine mount rib could compromise the structural integrity of the engine mount and could lead to subsequent detachment of an engine.
A new Time Limits/Maintenance Checks (TLMC) Airworthiness Limitations (AWL) task is introduced to ensure that any fatigue cracking of the engine mount rib is detected and corrected.
The original issue of this [Canadian] AD mandated the incorporation of a new TLMC AWL task [into the maintenance or inspection program, as applicable].
Revision 1 of this [Canadian] AD is issued to remove model CL- 600-1A11 (600) aeroplanes from the Applicability section of the [Canadian] AD since this model was incorrectly included in the original issue.

You may examine the MCAI in the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2017- 0338.

Comments

We gave the public the opportunity to participate in developing this AD. The following presents the comments received on the NPRM and the FAA's response to each comment.

Requests To Revise Applicability

Bombardier, Inc. (Bombardier) and NetJets Inc. (NetJets) requested that we revise paragraph (c)(3) of the proposed AD. The commenters explained that the Applicability should specify Model CL-600-2B16 (CL- 604 Variant) airplanes having serial numbers (S/Ns) 5301 through 5665 inclusive, and S/Ns 5701 through 5990 inclusive; instead of Model CL- 600-2B16 (CL-604 Variant) airplanes, having S/Ns 5301 through 5665 inclusive, and S/Ns 5701 and subsequent.
Bombardier stated that ``Challenger 650'' is a marketing designation for Model CL-600-2B16 (604 Variant) airplanes starting at S/N 6050, and ``Challenger 605'' is a marketing designation for Model CL-600-2B16 (604 Variant) airplanes having S/Ns 5701 to 5990. Bombardier and NetJets stated that future Model CL-600-2B16 (CL-604 Variant) airplanes having serial numbers subsequent to S/N 5990 do not require the proposed actions, explaining that task 54-50-00-103 (inspections of the engine mount rib) was first incorporated into the Time Limits/Maintenance Checks (TLMC) manual for Challenger 650 airplanes. Therefore, Bombardier asserts that operators of Challenger 650 airplanes should not be required to comply with the AD.
We agree with the commenters' requests. We have coordinated with TCCA and have verified that Model CL-

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600-2B16 (CL-604 Variant) airplanes having serial numbers subsequent to S/N 5990 should not be subject to the required actions. We have changed paragraph (c)(3) of this AD accordingly.

Requests To Clarify Method of Compliance (MOC) for Maintenance/ Inspection Program Revision

Bombardier requested that more details be provided on how to meet the intent of paragraph (g) of the proposed AD, which specifies contacting the FAA for a MOC for revising the maintenance or inspection program to incorporate maintenance tasks. Bombardier suggested that the AD should specify the revisions in which the tasks were incorporated into the TLMC manual. Bombardier also suggested that this would prevent operators with a proper TLMC from being subject to a future AD. Bombardier stated that the AD should specify the tasks to be incorporated in the maintenance schedule, in order to provide operators with a sufficient level of detail on the revisions to be made to their maintenance or inspection program.
NetJets requested that we identify the specific tasks that are to be incorporated into the maintenance or inspection program. NetJets noted that the MCAI provides the specific task numbers.
We partially agree. We agree that operators need to know which actions must be incorporated into their maintenance or inspection programs. Therefore, we have revised paragraph (g) of this AD to identify the actions that must be incorporated.
We do not agree to identify specific TLMC revisions in this AD. The service information specified in Note 1 to paragraph (g) of this AD provides guidance on the required actions. However, to specify the service information in paragraph (g) of this AD would require it to be incorporatedby reference in this AD. The service information identified in this AD does not meet the Office of the Federal Register's criteria for materials incorporated by reference. Therefore, we have not changed this AD in this regard.

Conclusion

We reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting this AD with the changes described previously and minor editorial changes. We have determined that these minor changes:
Are consistent with the intent that was proposed in the NPRM for correcting the unsafe condition; and
Do not add any additional burden upon the public than was already proposed in the NPRM.
We also determined that these changes will not increase the economic burden on any operator or increase the scope of this AD.

Costs of Compliance

We estimate that this AD affects 129 airplanes of U.S. registry. We estimate the following costs to comply with this AD:

EstimatedCosts ----------------------------------------------------------------------------------------------------------------
Cost per Cost on U.S.
Action Labor cost Parts cost product operators ---------------------------------------------------------------------------------------------------------------- Revision of maintenance or 1 work-hour x $85 per $0 $85 $10,965
inspection program. hour = $85. ----------------------------------------------------------------------------------------------------------------

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. ``Subtitle VII: Aviation Programs,'' describes in more detail the scope of the Agency's authority.
We are issuing this rulemaking under the authority described in ``Subtitle VII, Part A, Subpart III, Section 44701: General requirements.'' Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.
This AD is issued in accordance with authority delegated by the Executive Director, Aircraft Certification Service, as authorized by FAA Order 8000.51C. In accordance with that order, issuance of ADs is normally a function of the Compliance and Airworthiness Division, but during this transition period, the Executive Director has delegated the authority to issue ADs applicable to transport category airplanes to the Director of the System Oversight Division.

Regulatory FindingsWe determined that this AD will not have federalism implications under Executive Order 13132. This AD will 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.
For the reasons discussed above, I certify that this AD:
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);
3. Will not affect intrastate aviation in Alaska; and
4. 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.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.