2021-08053. Airworthiness Directives; MHI RJ Aviation ULC (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for MHI RJ Aviation ULC Model CL-600-2C10 (Regional Jet Series 700, 701 & 702), CL-600-2C11 (Regional Jet Series 550), CL-600-2D15 (Regional Jet Series 705), CL-600-2D24 (Regional Jet Series 900), and CL-600-2E25 (Regional Jet Series 1000) airplanes. This proposed AD was prompted by reports and a design review indicating that there could be possible corrosion on the main landing gear (MLG) outer cylinder at the interface with the gland nut on the shock strut installation and on the forward and aft trunnion pins in the MLG dressed shock strut assembly. This proposed AD would require detailed inspections for corrosion on the MLG outer cylinder assemblies, certain MLG dressed shock strut assemblies, and the MLG outer cylinder at the gland nut threads, thread relief groove, and chamfer; a detailed inspection for the presence of corrosion-inhibiting compound (CIC) on the MLG forward and aft trunnion pins and grease adapter assemblies; applicable corrective actions; application of primer, paint, and CIC as applicable; re-identification of certain part numbers; and marking of the MOD STATUS field of the nameplate of certain parts. The FAA is proposing this AD to address the unsafe condition on these products.

DATES:

The FAA must receive comments on this proposed AD by June 4, 2021.

ADDRESSES:

You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:

• Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: [phone].
• Mail: U.S. Department of Transportation, Docket Operations,M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.
• Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For Bombardier service information identified in this NPRM, contact MHI RJ Aviation ULC, 12655 Henri-Fabre Blvd., Mirabel, Québec J7N 1E1 Canada; Widebody Customer Response Center North America toll-free telephone [phone] or direct-dial telephone [phone]; fax [phone]; email [e-mail]; internet https://eservices.aero.bombardier.com.

You may view this service information at the FAA, Airworthiness Products Section, Operational Safety Branch, 2200 South 216th St., Des Moines, WA. For information on the availability of this material at the FAA, call 206-231-3195.

Examining the AD Docket

You may examine the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-0309; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this NPRM, any comments received, and other information. The street address for Docket Operations is listed above.

FOR FURTHER INFORMATION CONTACT:

Darren Gassetto, Aerospace Engineer, Mechanical Systems and Administrative Services Section, FAA, New York ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone [phone]; fax [phone]; email [e-mail].

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2021-0309; Project Identifier MCAI-2020-00918-T” at the beginning of your comments. The most helpful comments reference a specific portion of the proposal, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date and may amend the proposal because of those comments.

Except for Confidential Business Information (CBI) as described in the following paragraph, and other information as described in 14 CFR 11.35, the FAA will post all comments received, without change, to https://www.regulations.gov,, including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this proposed AD.

Confidential Business Information

CBI is commercial or financial information that is both customarily and actually treated as private by its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public disclosure. If your comments responsive to this NPRM contain commercial or financial information that is customarily treated as private, that you actually treat as private, and that is relevant or responsive to this NPRM, it is important that you clearly designate the submitted comments as CBI. Please mark each page of your submission containing CBI as “PROPIN.” The FAA will treat such marked submissions as confidential under the FOIA, and they will not be placed in the public docket of this NPRM. Submissions containing CBI should be sent to Darren Gassetto, Aerospace Engineer, Mechanical Systems and Administrative Services Section, FAA, New York ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone [phone]; fax [phone]; email [e-mail]. Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking.

Background

Transport Canada Civil Aviation (TCCA), which is the aviation authority for Canada, has issued TCCA AD CF-2019-17R1, dated June 18, 2020 (referred to after this as the Mandatory Continuing Airworthiness Information, or “the MCAI”), to correct an unsafe condition for MHI RJ Aviation ULC (type certificate previously held by Bombardier, Inc.) Model CL-600-2C10 (Regional Jet Series 700, 701 & 702) airplanes, Model CL-600-2C11 (Regional Jet Series 550) airplanes, Model CL-600-2D15 (Regional Jet Series 705) airplanes, CL-600-2D24 (Regional Jet Series 900) airplanes, and Model CL-600-2E25 (Regional Jet Series 1000) airplanes. You may examine the MCAI in the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-0309.

This proposed AD was prompted by reports and a design review indicating that there could be corrosion on the MLG outer cylinder assemblies and certain MLG dressed shock strut assemblies; primer was not correctly applied at the gland nut thread relief groove and chamfer areas on certain MLG outer cylinders during production; and CIC was inadvertently removed from certain MLG forward and aft trunnion pins and grease adapter assemblies during maintenance. The FAA is proposing this AD to address undetected corrosion on the MLG forward and aft trunnion pins, and the gland nut interface on certain MLG outer cylinders, which could result in an MLG collapse. See the MCAI for additional background information.

Related Service Information Under 1 CFR Part 51

Bombardier has issued the following service information.

• Service Bulletin 670BA-32-024, Revision C, dated February 11, 2015, which describes procedures for a detailed visual inspection of the MLG outer cylinder assemblies and dressed shock strut assemblies for corrosion of the outer cylinder gland nut thread interface and relief area, and corrective actions including repair and corrosion removal.
• Service Bulletin 670BA-32-034, Revision B, dated December 21, 2018, which describes procedures for a detailed visual inspection of the inside diameter of the MLG trunnion pins for discrepancies including the condition of paint and CIC and evidence of corrosion, and corrective actions including replacement and rework of the trunnion pins as applicable.
• Service Bulletin 670BA-32-039, dated February 29, 2012, which describes procedures for inspections of the inner diameter of the MLG forward and aft trunnion pins for discrepancies including corrosion and inadequate CIC, and corrective actions including application of CIC and replacement of corroded forward and aft trunnion pins with serviceable parts.
• Service Bulletin 670BA-32-052, dated February 9, 2015, which describes procedures for a detailed visual inspection of the gland nut thread relief groove and chamfer surface for the condition of the protective coating and for discrepancies including evidence of corrosion or rework at the gland nut thread relief groove and chamfer surface of the MLG shock strut outer cylinder assemblies, and corrective actions including corrosion removal.

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.

FAA's Determination

This product has been approved by the aviation authority of another country, and is approved for operation in the United States. Pursuant to the FAA's bilateral agreement with the State of Design Authority, the FAA has been notified of the unsafe condition described in the MCAI and service information referenced above. The FAA is proposing this AD because the FAA evaluated all the relevant information and determined the unsafe condition described previously is likely to exist or develop on other products of the same type design.

Proposed Requirements of This NPRM

This proposed AD would require accomplishing the actions specified in the service information described previously, except as discussed under “Differences Between this Proposed AD and the MCAI or Service Information.”

Differences Between This Proposed AD and the MCAI or Service Information

Although certain service information specifies to return damaged MLG trunnion pins to Goodrich Landing Gear, that action would not be required by this proposed AD.

Costs of Compliance

The FAA estimates that this proposed AD affects 562 airplanes of U.S. registry. The FAA estimates the following costs to comply with this proposed AD:

Estimated Costs for Required Actions

Labor cost	Parts cost	Cost per product	Cost on U.S. operators
Up to 100 work-hours × $85 per hour = Up to $8,500	Up to $36,604	Up to $45,104	Up to $25,348,448.

According to the manufacturer, some or all of the costs of this proposed AD may be covered under warranty, thereby reducing the cost impact on affected operators. The FAA does not control warranty coverage for affected operators. As a result, the FAA has included all known costs in our cost estimate.

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.

The FAA is 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

The FAA determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD 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.

For the reasons discussed above, I certify this proposed regulation:

(1) Is not a “significant regulatory action” under Executive Order 12866,

(2) Would not affect intrastate aviation in Alaska, and

(3) Would 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

The Proposed Amendment

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

PART 39—AIRWORTHINESS DIRECTIVES

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

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

§ 39.13

[Amended]

2. The FAA amends § 39.13 by adding the following new airworthiness directive:

MHI RJ Aviation ULC (Type Certificate Previously Held by Bombardier, Inc.): Docket No. FAA-2021-0309; Project Identifier MCAI-2020-00918-T.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by June 4, 2021.

(b) Affected ADs

None.

(c) Applicability

This AD applies to the MHI RJ Aviation ULC (type certificate previously held by Bombardier, Inc.) airplanes, certificated in any category, specified in paragraphs (c)(1) through (3) of this AD.

(1) Model CL-600-2C10 (Regional Jet Series 700, 701 & 702) and Model CL-600-2C11 (Regional Jet Series 550) airplanes, serial numbers 10002 and subsequent.

(2) Model CL-600-2D15 (Regional Jet Series 705) airplanes and CL-600-2D24 (Regional Jet Series 900) airplanes, serial numbers 15001 and subsequent.

(3) Model CL-600-2E25 (Regional Jet Series 1000) airplanes, serial numbers 19001 and subsequent.

(d) Subject

Air Transport Association (ATA) of America Code 32, Landing Gear.

(e) Reason

This AD was prompted by reports and a design review indicating that there could be corrosion on the main landing gear (MLG) outer cylinder assemblies at the interface with the gland nut on the shock strut installation and on the forward and aft trunnion pins in the MLG dressed shock strut assemblies; primer was not correctly applied at the gland nut thread relief groove and chamfer areas on certain MLG outer cylinders during production; and corrosion-inhibiting compound (CIC) could have inadvertently been removed from certain MLG forward and aft trunnion pins and grease adapter assemblies during maintenance. The FAA is issuing this AD to address undetected corrosion on the MLG forward and aft trunnion pins, and the gland nut interface on certain MLG outer cylinders, which could result in an MLG collapse.

(f) Compliance

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

(g) Inspection and Application of Corrosion Protection for MLG Outer Cylinder Assemblies and Certain MLG Dressed Shock Strut Assemblies

For airplanes identified in paragraphs (c)(1) and (2) of this AD with MLG outer cylinder assemblies and MLG dressed shock strut assemblies having part numbers and serial numbers specified in the effectivity tables in Section 1.A.(1) of Bombardier Service Bulletin 670BA-32-024, Revision C, dated February 11, 2015 (Bombardier Service Bulletin 670BA-32-024, Revision C): At the applicable time specified in paragraph (g)(1) or (2) of this AD, do a detailed visual inspection for corrosion and all other required actions specified in, and in accordance with, Section 2., Part A, of the Accomplishment Instructions of Bombardier Service Bulletin 670BA-32-024, Revision C.

(1) For MLG assemblies that have accumulated 12,500 total flight hours or less, and have been in service for 72 months or less from entry into service or the last overhaul date: Within 6,500 flight hours or 36 months, whichever comes first, after the effective date of this AD.

(2) For MLG assemblies that have accumulated more than 12,500 total flight hours, or have been in service for more than 72 months from entry into service or the last overhaul date: Within 3,500 flight hours or 24 months, whichever occurs first, after the effective date of this AD.

(h) Inspection of Certain Other MLG Dressed Shock Strut Assemblies and Corrective Action

For airplanes identified in paragraphs (c)(1) and (2) of this AD, equipped with MLG dressed shock strut assemblies having part numbers (P/Ns) 49000-25 through 49000-46 and P/Ns 49050-15 through 49050-22, on which the MLG active dynamic seal has been replaced with the spare dynamic seal as specified in Bombardier CRJ700/705/900/1000 Aircraft Maintenance Manual (AMM), CSP B-001, Task 32-11-10-960-802, Revision 37, dated November 25, 2011, or earlier: At the applicable time specified in paragraph (h)(1) or (2) of this AD, do a detailed visual inspection of the MLG dressed shock strut assemblies for corrosion, and all applicable corrective actions, in accordance with Section 2., Part B, of the Accomplishment Instructions of Bombardier Service Bulletin 670BA-32-024, Revision C.

(1) For MLG assemblies that have accumulated 12,500 total flight hours or less, and have been in service for 72 months or less from entry into service or the last overhaul date: Within 6,500 flight hours or 36 months, whichever comes first, after the effective date of this AD.

(2) For MLG assemblies that have accumulated more than 12,500 total flight hours, or have been in service for more than 72 months from entry into service or the last overhaul date: Within 3,500 flight hours or 24 months, whichever occurs first, after the effective date of this AD.

(i) Inspection of MLG Outer Cylinder at the Gland Nut threads, Thread Relief Groove, and Chamfer and Corrective Action

For airplanes identified in paragraphs (c)(1) through (3) of this AD equipped with MLG outer cylinder assemblies having part numbers and serial numbers specified in Section 1.A., Effectivity, of Bombardier Service Bulletin 670BA-32-052, dated February 9, 2015: Within 6,500 flight hours or 36 months, whichever occurs first after the effective date of this AD: Do a detailed visual inspection, of the MLG shock strut outer cylinder assemblies and do all other required actions specified in, and, in accordance with Section 2. of the Accomplishment Instructions of Bombardier Service Bulletin 670BA-32-052, dated February 9, 2015.

(j) Inspection of Certain MLG Forward and Aft Trunnion Pins, and Corrective Action

For airplanes identified in paragraphs (c)(1) through (3) of this AD equipped with MLG forward and aft trunnion pins and grease adapter assemblies having part numbers and serial numbers specified in Section 1.A., Effectivity, of Bombardier Service Bulletin 670BA-32-034, Revision B, dated December 21, 2018: At the applicable time specified in paragraph (j)(1) or (2) of this AD, do a detailed visual inspection of the MLG forward and aft trunnion pins and do all applicable corrective actions, in accordance with Section 2.B. and paragraphs 2.C.(6) and (8) of the Accomplishment Instructions of Bombardier Service Bulletin 670BA-32-034, Revision B, dated December 21, 2018.

Note 1 to paragraph (j):

The corrective action is applicable only to MLG forward and aft trunnion pins having P/Ns 49101-9, -11, and -13 reworked from P/Ns 49101-1, -5, and -7, as specified in the procedures in Goodrich Service Bulletin 49101-32-47, any revision. The corrective action is not applicable to MLG forward and aft trunnion pins having P/Ns 49101-9, -11, and -13 that were installed as original equipment or purchased from Goodrich Landing Gear.

(1) For MLG forward and aft trunnion pins and grease adapter assemblies that have not had the procedures specified in Goodrich Service Bulletin 49101-32-47, any revision, incorporated, at the applicable time specified in paragraph (j)(1)(i) or (ii) of this AD.

(i) For MLG forward and aft trunnion pins that have accumulated 10,000 total flight hours or less, and have been in service 60 months or less from the entry into service or last overhaul date: Within 6,500 flight hours or 36 months, whichever occurs first, after the effective date of this AD.

(ii) For MLG forward and aft trunnion pins that have accumulated more than 10,000 total flight hours, or have been in service for more than 60 months from entry into service or last overhaul date: Within 3,000 flight hours or 24 months, whichever occurs first, after the effective date of this AD.

(2) For MLG forward and aft trunnion pins that have had the procedures specified in Goodrich Service Bulletin 49101-32-47, any revision, incorporated: Within 6,500 flight hours or 36 months, whichever occurs first, after the effective date of this AD.

(k) Inspection of Certain Other MLG Trunnion Pins Having P/Ns 49101-9, 49101-11, and 49101-13, Maintained Using Certain Maintenance Instructions

For airplanes identified in paragraphs (c)(1) through (3) of this AD equipped with MLG forward and aft trunnion pins havingP/Ns 49101-9, 49101-11, and 49101-13 that were maintained in accordance with the tasks identified in paragraphs (k)(1) through (4) of this AD: Within 6,500 flight hours or 36 months after the effective date of this AD, whichever occurs first, do a detailed visual inspection of the MLG forward and aft trunnion pins, and do all applicable corrective actions, in accordance with Section 2. of the Accomplishment Instructions of Bombardier Service Bulletin 670BA-32-039, dated February 29, 2012.

(1) Bombardier CRJ700/705/900/1000 AMM, CSP B-001, Task 32-11-05-400-801 A01, Revision 31, dated March 20, 2010, or earlier.

(2) Bombardier CRJ700/705/900/1000 AMM, CSP B-001, Task 32-11-05-400-801 A02, Revision 34, dated November 20, 2010, or earlier.

(3) Bombardier CRJ700/705/900/1000 AMM, CSP B-001, Task 32-11-05-400-804 A01, Revision 35, dated March 20, 2011, or earlier.

(4) Bombardier CRJ700/705/900/1000 AMM, CSP B-001, Task 32-11-05-400-805 A01, Revision 35, dated March 20, 2011, or earlier.

Note 2 to paragraph (k):

The corrective action described in this paragraph is not applicable to MLG forward and aft trunnion pins having P/Ns 49101-9, -11, and -13 reworked from P/Ns 49101-1, -5, and -7 as specified in the procedures in Goodrich SB 49101-32-47, any revision. The corrective action described in this paragraph is applicable to MLG forward and aft trunnion pins having P/Ns 49101-9, -11, and -13 installed as original equipment or purchased from Goodrich Landing Gear.

(l) Credit for Previous Actions

(1) This paragraph provides credit for actions required by paragraph (g) of this AD, if those actions were performed before the effective date of this AD using Section 2., Part A, of the Accomplishment Instructions of Bombardier Service Bulletin 670BA-32-024, Revision B, dated December 19, 2012.

(2) This paragraph provides credit for actions required by paragraph (h) of this AD if those actions were performed before the effective date of this AD using Section 2., Part B, of the Accomplishment Instructions of Bombardier Service Bulletin 670BA-32-024, Revision B, dated December 19, 2012; or Bombardier CRJ700/705/900/1000 Aircraft Maintenance Manual (AMM), CSP B-001, Task 32-11-10-960-802, Revision 38, dated March 25, 2012.

(3) This paragraph provides credit for actions required by paragraph (j) of this AD if those actions were performed before the effective date of this AD using Section 2.B. and paragraphs 2.C.(6) and (8) of the Accomplishment Instructions of Bombardier Service Bulletin 670BA-32-034, dated February 29, 2012; or Revision A, dated August 17, 2012.

(4) This paragraph provides credit for actions required by paragraph (k) of this AD, if those actions were performed before the effective date of this AD using the service information specified in paragraphs (l)(4)(i) through (iv) of this AD.

(i) Bombardier CRJ700/900/1000 Aircraft Maintenance Manual (AMM), CSP B-001, Task 32-11-05-400-801 A01, Revision 38, dated March 25, 2012.

(ii) Bombardier CRJ700/900/1000 AMM, CSP B-001, Task 32-11-05-400-801 A02, Revision 38, dated March 25, 2012.

(iii) Bombardier CRJ700/900/1000 AMM, CSP B-001, Task 32-11-05-400-804 A01, Revision 37, dated November 25, 2011, for actions specified in Section 2.B.(1) of the Accomplishment Instructions of Bombardier Service Bulletin 670BA-32-039, dated February 29, 2012.

(iv) Bombardier CRJ700/900/1000 AMM, CSP B-001, Task 32-11-05-400-805 A01, Revision 37, dated November 25, 2011, for actions specified in Section 2.B.(2) of the Accomplishment Instructions of Bombardier Service Bulletin 670BA-32-039, dated February 29, 2012.

(m) No Requirement for Return of Parts

Although certain service information referenced in this AD specifies to return damaged MLG trunnion pins to Goodrich Landing Gear, this AD does not include that requirement.

(n) 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 [phone]; fax [phone]. 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 instructions from a manufacturer, the instructions must be accomplished using a method approved by the Manager, New York ACO Branch, FAA; or Transport Canada Civil Aviation (TCCA); or MHI RJ Aviation ULC's TCCA Design Approval Organization (DAO). If approved by the DAO, the approval must include the DAO-authorized signature.

(o) Related Information

(1) Refer to Mandatory Continuing Airworthiness Information (MCAI) TCCA AD CF-2019-17R1, dated June 18, 2020, for related information. This MCAI may be found in the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-0309.

(2) For more information about this AD, contact Darren Gassetto, Aerospace Engineer, Mechanical Systems and Administrative Services Section, FAA, New York ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone [phone]; fax [phone]; email [e-mail].

(3) For Bombardier service information identified in this AD, contact MHI RJ Aviation ULC, 12655 Henri-Fabre Blvd., Mirabel, Québec J7N 1E1 Canada; Widebody Customer Response Center North America toll-free telephone [phone] or direct-dial telephone [phone]; fax [phone]; email [e-mail]; internet https://eservices.aero.bombardier.com. You may view this service information at the FAA, Airworthiness Products Section, Operational Safety Branch, 2200 South 216th St., Des Moines, WA. For information on the availability of this material at the FAA, call 206-231-3195.

Issued on April 13, 2021.

Lance T. Gant,

Director, Compliance & Airworthiness Division, Aircraft Certification Service.