AD 2016-19-17

We are superseding Airworthiness Directive (AD) 2010-23-19 for certain Bombardier, Inc. Model CL-600-2C10 (Regional Jet Series 700, 701, and 702) airplanes, Model CL-600-2D15 (Regional Jet Series 705) airplanes, and Model CL-600-2D24 (Regional Jet Series 900) airplanes. AD 2010-23-19 required repetitive inspections for damage of the main landing gear (MLG) inboard doors and fairing, and corrective actions if necessary. This new AD requires repetitive inspections for damage of the MLG inboard doors, MLG fairing, and adjacent structures of the MLG inboard doors, and corrective actions if necessary; replacement of the MLG fairing seal; and a terminating action involving increasing the clearances between the MLG fairing and MLG door. This new AD also adds one airplane and removes others from the applicability. This AD was prompted by reports of the MLG failing to fully extend. We are issuing this AD to prevent loss of controllability of the airplane during landing.

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 removing Airworthiness Directive (AD) 2010-23-19, Amendment 39-16508 (75 FR 68695, November 9, 2010), and adding the following new AD:

2016-19-17 Bombardier, Inc.: Amendment 39-18666; Docket No. FAA- 2015-8471; Directorate Identifier 2013-NM-153-AD.

(a) Effective Date

This AD is effective November 17, 2016.

(b) Affected ADs

This AD replaces AD 2010-23-19, Amendment 39-16508 (75 FR 68695, November 9, 2010) (``AD 2010-23-19'').

(c) Applicability

This AD applies to the Bombardier, Inc. airplanes identified in paragraphs (c)(1) and (c)(2) of this AD, certificated in any category.(1) Model CL-600-2C10 (Regional Jet Series 700, 701, & 702) airplanes, having serial numbers (S/Ns) 10002 through 10333 inclusive.
(2) Model CL-600-2D15 (Regional Jet Series 705) and CL-600-2D24 (Regional Jet Series 900) airplanes, having S/Ns 15001 through 15284 inclusive.

(d) Subject

Air Transport Association (ATA) of America Code 32: Landing gear.

(e) Reason

This AD was prompted by reports of the main landing gear (MLG) failing to fully extend. We are issuing this AD to prevent loss of controllability of the airplane during landing.

(f) Compliance

Comply with this AD within the compliance times specified, unless already done.

(g) Retained Repetitive Inspections and Corrective Actions, With New Service Information and Revised Repair Instructions

(1) This paragraph restates the requirements of paragraph (g) of AD 2010-23-19, with new service information. For airplanes having S/ Ns 10003 through 10313 inclusive, 15001 through 15238 inclusive, and 15240 through 15255 inclusive: Within 50 flight cycles after November 24, 2010 (the effective date of AD 2010-23-19), do the inspections specified in paragraphs (g)(1)(i) through (g)(1)(iv) of this AD, in accordance with ``PART A--Inspection of the MLG Inboard Doors, MLG Fairing and Adjacent Structure,'' of the Accomplishment Instructions of Bombardier Alert Service Bulletin A670BA-32-030, Revision A, dated October 22, 2010; or Bombardier Alert Service Bulletin A670BA-32-030, Revision D, dated August 6, 2013; as applicable. As of the effective date of this AD, use only Bombardier Alert Service Bulletin A670BA-32-030, Revision D, dated August 6, 2013, to accomplish the actions required by this paragraph. Repeat the inspections thereafter at intervals not to exceed 600 flight hours.
(i) Do a detailed inspection for damage (including wear lines, cracks, fraying, tears, and evidence of chafing) of the rubber seal of the MLG fairing.
(ii) Do a detailed inspection for damage(including missing and broken rollers, loose and missing fasteners, and damaged and missing stops) of the MLG inboard doors, and for damage along the edge of the MLG inboard door adjacent to the MLG fairing.
(iii) Do a detailed inspection of the MLG fairing for damage (including missing forward and aft stops, and loose and missing fasteners), and for damage along the edge of the MLG fairing adjacent to the MLG door.
(iv) Do a detailed inspection for damage (including missing stops, loose and missing fasteners, and missing wedges) of the stops and wedges on the forward and aft spars.
(2) This paragraph restates the requirements of paragraph (h) of AD 2010-23-19, with revised service information. For airplanes not identified in paragraph (g)(1) of this AD, excluding the airplane having S/N 10002, and excluding airplanes having MLG fairing seals having part numbers (P/Ns) CC670-39244-5 and CC670-39244-6: Within 600 flight hours after November 24, 2010 (the effective date of AD 2010-23-19), do the inspections specified in paragraphs (g)(2)(i) through (g)(2)(iv) of this AD, in accordance with ``PART A-- Inspection of the MLG Inboard Doors, MLG Fairing and Adjacent Structure,'' of the Accomplishment Instructions of Bombardier Alert Service Bulletin A670BA-32-030, Revision A, dated October 22, 2010; or Bombardier Alert Service Bulletin A670BA-32-030, Revision D, dated August 6, 2013. As of the effective date of this AD, use only Bombardier Alert Service Bulletin A670BA-32-030, Revision D, dated August 6, 2013, to accomplish the actions required by this paragraph. Repeat the inspections thereafter at intervals not to exceed 600 flight hours.
(i) Do a detailed inspection for damage (including wear lines, cracks, fraying, tears, and evidence of chafing) of the rubber seal of the MLG fairing.

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(ii) Do a detailed inspection for damage (including missing and broken rollers, loose and missing fasteners, and damaged and missing stops) of the MLG inboard doors, and for damage along the edge of the MLG inboard door adjacent to the MLG fairing.
(iii) Do a detailed inspection of the MLG fairing for damage (including missing forward and aft stops, and loose and missing fasteners), and for damage along the edge of the MLG fairing adjacent to the MLG door.
(iv) Do a detailed inspection for damage (including missing stops, loose and missing fasteners, and missing wedges) of the stops and wedges on the forward and aft spars.
(3) This paragraph restates the requirements of paragraph (i) of AD 2010-23-19, with revised service information. If damage to only the rubber seal on the MLG fairing is found during any inspection required by paragraph (g)(1) or (g)(2) of this AD, before further flight, do either action specified in paragraph (g)(3)(i) or (g)(3)(ii) of this AD.
(i) Replace the rubber seal on the MLG fairing with a new rubber seal, in accordance with ``PART B--Replacement of the Forward Rubber Seal on the MLG Fairing,'' of the Accomplishment Instructions of Bombardier Alert Service Bulletin A670BA-32-030, Revision A, dated October 22, 2010; or the Accomplishment Instructions of Bombardier Alert Service Bulletin A670BA-32-030, Revision D, dated August 6, 2013. As of the effective date of this AD, use only Bombardier Alert Service Bulletin A670BA-32-030, Revision D, dated August 6, 2013, to accomplish the actions required by this paragraph.
(ii) Remove the MLG inboard door, in accordance with ``PART C-- Removal of MLG Inboard Door,'' of the Accomplishment Instructions of Bombardier Alert Service Bulletin A670BA-32-030, Revision A, dated October 22, 2010; or Bombardier Alert Service Bulletin A670BA-32- 030, Revision D, dated August 6, 2013. For airplanes on which the MLG inboard door is re-installed, do the installation of the MLG inboard door in accordance with ``PART D--Installation of MLG Inboard Door,'' of the Accomplishment Instructions of Bombardier Alert Service Bulletin A670BA-32-030, Revision A, dated October 22, 2010; or Bombardier Alert Service Bulletin A670BA-32-030, Revision D, dated August 6, 2013. As of the effective date of this AD, use only Bombardier Alert Service Bulletin A670BA-32-030, Revision D, dated August 6, 2013, to accomplish the actions required by this paragraph.
(4) This paragraph restates the requirements of paragraph (j) of AD 2010-23-19, with revised repair instructions. If damage other than the damage identified in paragraph (g)(3) of this AD is found during any inspection required by paragraph (g)(1) or (g)(2) of this AD, before further flight, contact the Bombardier Regional Aircraft Customer Response Center for repair instructions and do the repair; or repair using a method approved by the Manager, New York Aircraft Certification Office (ACO), ANE-170, FAA; or Transport Canada Civil Aviation (TCCA); or Bombardier, Inc.'s TCCA Design Approval Organization (DAO). As of the effective date of this AD, if damage other than the damage identifiedin paragraph (g)(3) of this AD is found during any inspection required by paragraph (g)(1) or (g)(2) of this AD, before further flight, repair using a method approved by the Manager, New York Aircraft Certification Office (ACO), ANE-170, FAA; or TCCA; or Bombardier, Inc.'s TCCA DAO.

(h) New Inspections of MLG Fairing Seal Having P/N CC670-39244-1 or CC670-39244-2

For airplanes on which an MLG fairing seal having P/N CC670- 39244-1 or P/N CC670-39244-2 is installed: At the applicable time specified in paragraph (i)(1) of this AD, do the inspections specified in paragraphs (h)(1) through (h)(4) of this AD, in accordance with the Accomplishment Instructions of Bombardier Alert Service Bulletin A670BA-32-030, Revision D, dated August 6, 2013, except as specified in paragraph (o) of this AD. Repeat the inspections thereafter at the time specified in paragraph (i)(2) of this AD.
(1) Do a detailed inspection for damage (including cracking, cuts, and tears in the material (fabric/rubber)) of the MLG fairing and seal.
(2) Do a detailed inspection for damage (including missing and broken rollers, loose and missing fasteners, and damaged and missing stops) of the MLG inboard doors, and for damage along the edge of the MLG inboard door adjacent to the MLG fairing.
(3) Do a detailed inspection of the MLG fairing for damage (including missing forward and aft stops, and loose and missing fasteners), and for damage (including, but not limited to, corrosion, cracking, and dents) along the edge of the MLG fairing adjacent to the MLG door.
(4) Do a detailed inspection for damage (including missing stops, loose and missing fasteners, and missing wedges) of the stops and wedges on the forward and aft spars.

(i) New Compliance Times for the Actions Required by Paragraph (h) of This AD

This paragraph specifies the compliance times for the actions required by paragraph (h) of this AD.
(1) The initial compliance time is specified in paragraphs (i)(1)(i)and (i)(1)(ii) of this AD.
(i) For airplanes having S/Ns 10002 through 10313 inclusive; 15001 through 15238 inclusive; and S/Ns 15240 through 15255 inclusive: Within 50 flight cycles after the effective date of this AD.
(ii) For all other airplane serial numbers: Within 600 flight hours after the effective date of this AD.
(2) Repeat the inspections specified in paragraph (h) of this AD at the earlier of the times specified in paragraphs (i)(2)(i) and (i)(2)(ii) of this AD.
(i) Repeat the inspections within 200 flight hours after the effective date of this AD. Repeat the inspections thereafter at intervals not to exceed 200 flight hours.
(ii) Repeat the inspections within 600 flight hours after the most recent inspection done in accordance with the requirements of AD 2010-23-19. Repeat the inspections thereafter at intervals not to exceed 200 flight hours.

(j) New Corrective Actions

(1) If any damage to the MLG fairing seal is found during any inspection required by paragraph (h) of this AD: Before further flight, do the actions specified in paragraph (j)(1)(i) or (j)(1)(ii) of this AD, except as specified in paragraph (o) of this AD.
(i) Before further flight, remove the MLG inboard doors, in accordance with Part C of the Accomplishment Instructions of Bombardier Alert Service Bulletin A670BA-32-030, Revision D, dated August 6, 2013. For airplanes on which the MLG inboard door is re- installed, do the installation of the MLG inboard door in accordance with Part D of the Accomplishment Instructions of Bombardier Alert Service Bulletin A670BA-32-030, Revision D, dated August 6, 2013.
(ii) Before further flight, replace the MLG fairing seals, in accordance with Part E of the Accomplishment Instructions of Bombardier Alert Service Bulletin A670BA-32-030, Revision D, dated August 6, 2013. Within 200 flight hours after installing the MLG fairing seals, do the actions required by paragraph (h) of this AD.
(2) If any damage other than that specified in paragraph (j)(1) of this AD is found, or if parts or fasteners are found missing, during any inspection required by paragraph (h) of this AD, before further flight, repair using a method approved by the Manager, New York ACO, ANE-170, FAA; or TCCA; or Bombardier, Inc.'s TCCA DAO.

(k) New Replacement of MLG Fairing Seals

Within 2,500 flight hours or 12 months, whichever occurs first, after the effective date of this AD: Replace any MLG fairing seals having P/Ns CC670-39244-1 and CC670-39244-2 with P/Ns CC670-39244-5 and CC670-39244-6, respectively, in accordance with Part E of the Accomplishment Instructions of Bombardier Alert Service Bulletin A670BA-32-030, Revision D, dated August 6, 2013, except as specified in paragraph (o) of this AD.

(l) New MLG Fairing Seal Post-Replacement Inspections

Within 600 flight hours after installing fairing seals having P/ Ns CC670-39244-5 or CC670-39244-6: Do the inspections specified in paragraphs (h)(1) through(h)(4) of this AD, in accordance with the Accomplishment Instructions of Bombardier Alert Service Bulletin A670BA-32-030, Revision D, dated August 6, 2013. If any damage to the MLG fairing seal is found during any inspection required by this paragraph: Before further flight, do the applicable actions specified in paragraph (j)(1) or (j)(2) of this AD. If no damage is found during any inspection required by this paragraph, repeat the inspections specified in paragraphs (h)(1) through (h)(4) of this AD thereafter at intervals not to exceed 600 flight hours, except as provided in paragraph (m) of this AD.

(m) New Exception to MLG Fairing Seal Post-Replacement Inspections

After accomplishment of the initial inspections specified in paragraph (l) of this AD, removal of the MLG inboard door, in accordance with the Accomplishment

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Instructions of Bombardier Alert Service Bulletin A670BA-32-030, Revision D, dated August 6, 2013, defers the repetitive inspections required by paragraph (l) of this AD until the MLG inboard door is re-installed. For airplanes on which the MLG inboard door is re- installed, do the installation of the MLG inboard door in accordance with the Accomplishment Instructions of Bombardier Alert Service Bulletin A670BA-32-030, Revision D, dated August 6, 2013, except as specified in paragraph (o) of this AD; and before the accumulation of 600 flight hours on the MLG inboard door since the actions required by paragraph (k) of this AD were accomplished, do the inspections specified in paragraph (l) of this AD, and repeat the inspections thereafter at the applicable time specified in paragraph (l) of this AD.

(n) New Terminating Modification

Within 6,600 flight hours or 36 months, whichever occurs first after the effective date of this AD: Modify the airplane by increasing the clearance between the left and right MLG fairings and the left and right MLG doors; and do all applicable related investigative and corrective actions; in accordance with the Accomplishment Instructions of Bombardier Service Bulletin 670BA-32- 040, Revision F, dated February 11, 2016, including Appendix A, Revision A, and Appendix B, Revision B, both dated July 12, 2014, except as provided by paragraph (o) of this AD. Do all applicable related investigative and corrective actions before further flight. If an MLG door has been removed, the modification may be delayed until the MLG door is re-installed in accordance with the Accomplishment Instructions of Bombardier Alert Service Bulletin A670BA-32-030, Revision D, dated August 6, 2013. Accomplishing this modification terminates the requirements of paragraphs (g) through (m) of this AD for that MLG door.

(o) Exceptions to Bombardier Service Information

Where Bombardier Alert Service Bulletin A670BA-32-030, Revision D, dated August 6, 2013; and Bombardier Service Bulletin 670BA-32- 040, Revision F, dated February 11, 2016, including Appendix A, Revision A, and Appendix B, Revision B, dated July 12, 2014; specify to contact the Bombardier Customer Response Center for an analysis or to get an approved disposition, repair using a method approved by the Manager, New York ACO, ANE-170, FAA; or TCCA; or Bombardier, Inc.'s TCCA DAO.

(p) Credit for Previous Actions

(1) This paragraph restates the provisions of paragraph (l) of AD 2010-23-19, with additional service information. This paragraph provides credit for the actions required by paragraph (g) of this AD, if those actions were performed before November 24, 2010 (the effective date of AD 2010-23-19), using Bombardier Alert Service Bulletin A670BA-32-030, dated October 18, 2010; or Bombardier Alert Service Bulletin A670BA-32-030, Revision A, dated October 22, 2010.
(2) This paragraph provides credit for the corresponding actions required by paragraphs (g)(1), (g)(2), (g)(3)(i), (g)(3)(ii), (h), (j)(1), (k), (l), (m), and (n) of this AD, if those actions were performed before the effective date of this AD using the service information specified in paragraph (p)(2)(i), (p)(2)(ii), or (p)(2)(iii) of this AD.
(i) Bombardier Alert Service Bulletin A670BA-32-030, Revision A, including Appendix A, dated October 22, 2010.
(ii) Bombardier Alert Service Bulletin A670BA-32-030, Revision B, dated November 3, 2011.
(iii) Bombardier Alert Service Bulletin A670BA-32-030, Revision C, dated March 13, 2013.
(3) This paragraph provides credit for the corresponding actions required by paragraph (n) of this AD, if those actions were performed before the effective date of this AD using the service information specified in paragraph (p)(3)(i), (p)(3)(ii), (p)(3)(iii), (p)(3)(iv), or (p)(3)(v) of this AD.
(i) Bombardier Service Bulletin 670BA-32-040, Revision A, dated March 13, 2013.
(i) Bombardier Service Bulletin 670BA-32-040, Revision B, dated August 6, 2013.
(iii) Bombardier Service Bulletin 670BA-32-040, Revision C, dated November 1, 2013.
(iv) Bombardier Service Bulletin 670BA-32-040, Revision D, dated July 2, 2014.
(v) Bombardier Service Bulletin 670BA-32-040, Revision E, dated November 13, 2014.

(q) Other FAA AD Provisions

The following provisions also apply to this AD:
(1) Alternative Methods of Compliance (AMOCs): The Manager, New York ACO, ANE-170, 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 ACO, send it to ATTN: Program Manager, Continuing Operational Safety, FAA, New York ACO, 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: As of the effective date of this AD, 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, ANE-170, FAA; or TCCA; or Bombardier, Inc.'s TCCA DAO. If approved by the DAO, the approval must include the DAO-authorized signature.

(r) Related Information

(1) Refer to Mandatory Continuing Airworthiness Information (MCAI) Canadian Airworthiness Directive CF-2010-36R1, dated July 18, 2013, 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-2015-8471.
(2) Service information identified in this AD that is not incorporated by reference is available at the addresses specified in paragraphs (s)(3) and (s)(4) of this AD.

(s) Material Incorporated by Reference

(1) The Director of the Federal Register approved the incorporation byreference (IBR) of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) You must use this service information as applicable to do the actions required by this AD, unless this AD specifies otherwise.
(i) Bombardier Alert Service Bulletin A670BA-32-030, Revision D, dated August 6, 2013.
(ii) Bombardier Service Bulletin 670BA-32-040, Revision F, dated February 11, 2016, including the following appendices.
(A) Appendix A, Revision A, dated July 12, 2014.
(B) Appendix B, Revision B, dated July 12, 2014.
(3) For service information identified in this AD, contact Bombardier, Inc., 400 C[ocirc]te-Vertu Road West, Dorval, Qu[eacute]bec H4S 1Y9, Canada; telephone 514-855-5000; fax 514-855- 7401; email thd.crj@aero.bombardier.com; Internet http://www.bombardier.com.
(4) You may view this service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. For information on the availability of this materialat the FAA, call 425-227-1221.
(5) You may view this service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2010-23-19, Amendment 39-16508 (75 FR 68695, November 9, 2010) (``AD 2010-23-19''). AD 2010-23-19 applied to certain Bombardier, Inc. Model CL-600-2C10 (Regional Jet Series 700, 701, and 702) airplanes, Model CL-600-2D15 (Regional Jet Series 705) airplanes, and Model CL-600-2D24 (Regional Jet Series 900) airplanes. The NPRM published in the Federal Register on January 20, 2016 (81 FR 3038) (``the NPRM''). The NPRM was prompted by reports of the MLG failing to fully extend. The NPRM proposed to continue to require repetitive inspections for damage of the MLG inboard doors and fairing, and corrective actions if necessary. The NPRM also proposed to require repetitive inspections for damage of the MLG inboard doors, MLG fairing, and adjacent structures of the MLG inboard doors, and corrective actions if necessary; replacement of the MLG fairing seal; anda terminating action involving increasing the clearances between the MLG fairing and MLG door. The NPRM also proposed to add one airplane and remove others from the applicability. We are issuing this AD to prevent loss of controllability of the airplane during landing.
Transport Canada Civil Aviation (TCCA), which is the aviation authority for Canada, has issued Airworthiness Directive CF-2010-36R1, dated July 18, 2013 (referred to after this as the Mandatory Continuing Airworthiness Information, or ``the MCAI''), to correct an unsafe condition on certain Bombardier, Inc. Model CL-600-2C10 (Regional Jet Series 700, 701, and 702) airplanes, Model CL-600-2D15 (Regional Jet Series 705) airplanes, and Model CL-600-2D24 (Regional Jet Series 900) airplanes. The MCAI states:

Two cases of main landing gear (MLG) failure to fully extend have been reported. An MLG failing to extend may result in an unsafe asymmetric landing configuration.
Preliminary investigation has shown that interference between the MLG door and the MLG fairing seal prevented the MLG door from opening.
This [Canadian] AD mandates the [detailed] inspection [for damage] and rectification [corrective action], as required, of the MLG fairing and seal, MLG door, and adjacent structures.
Data collected from the Original Issue of this [Canadian] AD shows potential deficiencies with the inspection. This [Canadian] AD is revised to update the applicability section and to introduce additional mitigating actions and the terminating action [a modification that includes related investigative actions, and corrective action if necessary].

The unsafe condition is the loss of controllability of the airplane during landing. Damage includes the following:
For the MLG fairing seal: Cracks, cuts, or tears in the material of the MLG

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fairing seal, and cuts in the material base.
For the MLG inboard doors: Missing or broken rollers on the MLG inboard door, missing stops, looseor missing fasteners from the stops, and damage (including, but not limited to, corrosion, cracking, and dents) along the edge of the MLG inboard door adjacent to the MLG fairing.
For the MLG fairing: Missing forward and aft stops, loose or missing fasteners from the forward and aft stops, and damage (including, but not limited to, corrosion, cracking, and dents) along the edge of the MLG fairing adjacent to the MLG inboard door.
For the stops and wedges on the forward and aft spars: Missing stops, loose or missing fasteners from the stops, missing wedges, and loose or missing fasteners from the wedges.
Corrective actions include replacement of MLG fairing seals, and increasing the clearances between the MLG fairing and MLG door.
The terminating modification involves increasing the clearance between the left and right MLG fairings and the left and right MLG doors. Related investigative actions for the terminating modification include the following inspections:
A detailedinspection of the MLG fairing for missing forward and aft stops, loose or missing fasteners from the forward and aft stops, and damage along the edge of the MLG fairing adjacent to the MLG inboard door.
A detailed visual inspection of the MLG inboard door for missing or broken rollers on the MLG inboard door, missing stops, loose or missing fasteners from the stops, and damage along the edge of the MLG inboard door adjacent to the MLG fairing.
A detailed visual inspection on the stops and wedges on the forward and aft spars for missing stops, loose or missing fasteners from the stops, missing wedges, and loose or missing fasteners from the wedges.
A liquid penetrant inspection or an eddy current inspection for cracks in the aft stop-fitting and stiffener of the forward member of the MLG inboard door.
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-2015- 8471.

Comments

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

Support for the NPRM

The Air Line Pilots Association, International (ALPA), stated that it supports the proposed requirements.

Request To Revise Preflight Check

ALPA requested that we mandate a flightcrew check of the MLG door from the rear during preflight checks of the aft portion of the MLG. ALPA stated that an informal poll of ALPA carriers suggested that there is not a universally required position from which to make such a check. ALPA suggested that including a specific MLG fairing seal check in the preflight procedures would enhance the preflight inspection.
We do not agree with the commenter's request. The door seals have numerous marks and the only way to determine if there is significant damage to the MLG door fairing and seal would be to perform a detailed inspection as specified in Bombardier Alert Service Bulletin A670BA-32- 030. Flightcrews are not trained to accomplish this inspection and would not be able to accurately assess the damage during the limited time assigned for the preflight check. Canadian AD CF-2010-36R1, dated July 18, 2013, requires increasing the clearance between the MLG fairings and the MLG doors. The effectiveness of Canadian AD CF-2010- 36R1 is being monitored, and we have no information that the required modification is not effective. As of April 2016, Bombardier In-Service- Engineering has confirmed that there have been no reports of the MLG door being jammed in the MLG fairing on airplanes that have done the actions specified in Bombardier Service Bulletin 670BA-32-040. We have not changed this AD in this regard.

Revised Service Information

Bombardier, Inc. has issued Service Bulletin 670BA-32-040, Revision F, dated February 11, 2016, including Appendix A, Revision A, and Appendix B, Revision B, both dated July 12, 2014. This service information incorporates small editorial changes, which have no effect on airplanes that have incorporated prior revisions of this service information. We have revised paragraphs (n) and (o) of this AD to reference this service information as the appropriate source of service information for accomplishing the required actions in those paragraphs. We have also added a new paragraph (p)(3)(v) to this AD to give credit for accomplishment of the actions required by paragraph (n) of this AD, if those actions were performed before the effective date of this AD using Bombardier Service Bulletin 670BA-32-040, Revision E, dated November 13, 2014.

Clarification of Revised Repair Instruction

We have clarified the revised repair instructions in paragraph (g)(4) of this AD by specifying that, as of the effective date of this AD, if damage other than the damage identified in paragraph (g)(3) of this AD is found the repairs must be approved using a method approved by the Manager, New York Aircraft Certification Office (ACO), ANE-170, FAA; or Transport Canada Civil Aviation (TCCA); or Bombardier, Inc.'s TCCA Design Approval Organization (DAO).

Conclusion

We reviewed the available data, including the comment 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 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.

Related Service Information Under 1 CFR Part 51

Bombardier, Inc. has issued Alert Service Bulletin A670BA-32-030, Revision D, dated August 6, 2013, which describes procedures for an inspection of the MLG inboard doors, MLG fairing, and adjacent structure of the MLG inboard doors. This service information also describes procedures for replacing damaged MLG fairingseal(s) and for a clearance check of the MLG door or, if necessary, for removing and/or installing a MLG door.
Bombardier, Inc. has also issued Service Bulletin 670BA-32-040, Revision F, dated February 11, 2016, including Appendix A, Revision A, and Appendix B, Revision B, both dated July 12, 2014. This service information describes procedures for increasing the clearances between the fairing and the MLG inboard doors, and between the MLG fairing and adjacent structure of the MLG doors. This service information also describes procedures for adjusting the MLG doors.
This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.

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Costs of Compliance

We estimate that this AD affects 416 airplanes of U.S. registry.
The actions required by AD 2010-23-19 and retained in this AD take about 1 work-hour per product, at an average labor rate of $85 per work-hour. Based on these figures, the estimated cost of the actions that were required by AD 2010-23-19 is $85 per inspection cycle for each product.
We also estimate that it takes about 50 work-hours for each product to comply with the basic requirements of this AD. The average labor rate is $85 per work-hour. Based on these figures, we estimate the cost of this AD on U.S. operators to be $1,768,000, or $4,250 for each product.
In addition, we estimate that any necessary follow-on replacement actions would take about 24 work-hours and require parts costing $2,626, for a cost of $4,666 per product. We have no way of determining the number of aircraft that might need these actions.

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 thescope 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.

Regulatory Findings

We 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.