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Proposed Rule

Airworthiness Directives; Aerospatiale Model ATR42-200, -300, and -320 Airplanes

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

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AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Supplemental notice of proposed rulemaking (NPRM); reopening of comment period.

SUMMARY:

The FAA is revising an earlier NPRM for an airworthiness directive (AD) that applies to certain Aerospatiale Model ATR42-200, -300, and -320 airplanes. The original NPRM would have required doing repetitive inspections of the upper arms of the main landing gear (MLG) side braces for missing or inadequately bonded identification plates; replacing the upper arm if necessary; and replacing the side brace assembly with a modified part. The original NPRM resulted from an operator who reported experiencing an unlock warning for the MLG on the right side of the airplane. This action revises the original NPRM by proposing to require doing an ultrasonic inspection of the upper arm of the MLG side brace for any defects and related investigative/corrective actions if necessary, instead of replacing the upper arm if necessary. This action also adds airplanes to the applicability. We are proposing this supplemental NPRM to prevent cracking of the upper arms of the side braces of the MLG, which could result in failure of the MLG during landing and possible damage to the airplane and injury to the flightcrew and passengers.

DATES:

We must receive comments on this supplemental NPRM by January 9, 2006.

ADDRESSES:

Use one of the following addresses to submit comments on this supplemental NPRM.

  • DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
  • Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
  • Mail: Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590.
  • Fax: (202) 493-2251.
  • Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Contact Aerospatiale, 316 Route de Bayonne, 31060 Toulouse, Cedex 03, France, for service information identified in this proposed AD.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Tom Rodriguez, Aerospace Engineer, International Branch, ANM-116, Transport Airplane Directorate, FAA, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-1137; fax (425) 227-1149.

End Further Info End Preamble Start Supplemental Information

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any relevant written data, views, or arguments regarding this supplemental NPRM. Include the docket number “Docket No. FAA-2005-20220; Directorate Identifier 2004-NM-152-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this supplemental NPRM. We will consider all comments received by the closing date and may amend this supplemental NPRM in light of those comments.

We will post all comments submitted, without change, to http://dms.dot.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this supplemental NPRM. Using the search function of that Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov.

Examining the Docket

You may examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone (800) 647-5227) is located on the plaza level in the Nassif Building at the DOT street address stated in ADDRESSES. Comments will be available in the AD docket shortly after the Docket Management System receives them.

Discussion

We proposed to amend 14 CFR part 39 with a notice of proposed rulemaking (NPRM) for an airworthiness directive (AD) (the “original NPRM”). The original NPRM applies to certain Aerospatiale Model ATR42-200, -300, and -320 airplanes. The original NPRM was published in the Federal Register on February 1, 2005 (70 FR 5081). The original NPRM proposed to require doing repetitive inspections of the upper arms of the main landing gear (MLG) side braces for missing or inadequately bonded identification plates; replacing the upper arm if necessary; and replacing the side brace assembly with a modified part.

Relevant Service Information

Since the original NPRM was issued, Messier-Dowty has issued Special Inspection Service Bulletin 631-32-181, Revision 2, dated June 3, 2005. (Messier-Dowty Special Inspection Service Bulletin 631-32-175, dated January 7, 2004, was referenced in the original NPRM as the appropriate source of service information for doing the repetitive inspections and replacements of the upper arms if necessary.) Revision 2 of the service bulletin describes procedures for doing repetitive visual inspections of the upper arms of the MLG side brace assemblies for missing or partially unstuck identification plates and beads of glue. If any identification plate or bead of glue is missing or partially unstuck, the service bulletin also describes procedures for doing an ultrasonic inspection of the upper arm of the MLG side brace for any defects and doing related investigative and corrective actions if necessary. The related investigative action is a visual inspection of the MLG side brace surface for any paint tears, scratches, or corrosion prior to accomplishing the ultrasonic inspection. The corrective actions include the following: Start Printed Page 73672

  • If any paint tear, scratch, or corrosion is found on the surface of the upper arm, removing the contamination prior to doing the ultrasonic inspection.
  • If the echo is less than 20%, restoring the plate areas and reidentifying the identification plate.
  • If the echo is 20% or greater, replacing the MLG side brace with an MLG side brace equipped with an airworthy upper arm.

Accomplishing the actions specified in Messier-Dowty Special Inspection Service Bulletin 631-32-181, Revision 2, and the replacements in Messier-Dowty Service Bulletin 631-32-176, Revision 1, dated June 2, 2004, is intended to adequately address the unsafe condition. (Messier-Dowty Service Bulletin 631-32-176, Revision 1, was referenced in the original NPRM as the appropriate source of service information for replacing a side brace assembly with a modified part.) The Direction Generale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, mandated the service information and issued French airworthiness directive F-2005-106, dated July 6, 2005, to ensure the continued airworthiness of these airplanes in France. French airworthiness directive F-2005-106 supersedes French airworthiness directive F-2004-006, dated January 7, 2004, which was referenced as related information in paragraph (l) of the original NPRM. French airworthiness directive F-2005-106 also adds new airplanes to the applicability. We have revised the applicability of the supplemental NPRM to match French airworthiness directive F-2005-106.

Clarification Between the Supplemental NPRM and Service Bulletin

Where Messier-Dowty Special Inspection Service Bulletin 631-32-181, Revision 2, specifies replacing a side brace with a side brace equipped with an airworthy upper arm, this supplemental NPRM proposes to replace it with a side brace equipped with an upper arm modified in accordance with Messier-Dowty Service Bulletin 631-32-176, Revision 1.

Clarification of Inspection Terminology

The “visual inspection” specified in Revision 2 of Messier-Dowty Special Inspection Service Bulletin 631-32-181 is referred to as a “general visual inspection” in this supplemental NPRM. We have included the definition for a general visual inspection in a note in the supplemental NPRM.

Clarification of Alternative Method of Compliance (AMOC) Paragraph

We have revised this supplemental NPRM to clarify the appropriate procedure for notifying the principal inspector before using any approved AMOC on any airplane to which the AMOC applies.

Comments

We have considered the following comments on the original NPRM.

Request to Use AMOC

One commenter requests that we revise the original NPRM to allow operators a means for mitigating any corrosion and reidentifying the upper arms of the MLG side braces, rather than proposing to require replacement of the upper arms. The commenter suggests that a combination of blending, coating, and a part identification method such as electro-etching would be a more appropriate solution to address the unsafe condition of the original NPRM. The commenter states that electro-etching would have minimal structural impact on the upper arms, while providing a permanent mark that can only be removed by grinding.

We partially agree. As stated previously, if any identification plate or bead of glue is missing or partially unstuck, this supplemental NPRM proposes to require doing an ultrasonic inspection of the upper arm of an MLG side brace for any defects (and doing related investigative and corrective actions if necessary), rather than proposing to replace the upper arm. Although, depending on the results of the ultrasonic inspection, operators may be required to replace the side brace assembly with a part modified in accordance with Messier-Dowty Service Bulletin 631-32-176, Revision 1. This supplemental NPRM also proposes to require modification of the side brace assemblies to terminate the repetitive visual inspections. However, under the provisions of paragraph (m) of the proposed final rule, we may consider requests for approval of an AMOC if sufficient data are submitted to substantiate that such a design change would provide an acceptable level of safety.

Request to Withdraw NPRM

The same commenter believes that the original NPRM is an overreaction to a single event, the cause of which can still be speculated upon. The commenter also believes that any potential unsafe condition can be addressed by other means. We infer the commenter requests that we withdraw the original NPRM.

We do not agree. Although the original NPRM was prompted by one report, we have identified an unsafe condition that is likely to exist or develop on other products of the same type design. The affected identification plates are located in a high stress area where they could be torn down. When an identification plate is torn down, the protective treatment on the upper arm of the MLG side brace could be damaged or stripped. Damaged or stripped protective treatment could lead to corrosion and consequent cracking of the upper arms of the MLG side braces. We have also considered the action taken by the authority of the state of design and the manufacturer's recommendation. Cracking of the upper arms of the side braces of the MLG, if not corrected, could result in failure of the MLG during landing and possible damage to the airplane and injury to the flightcrew and passengers.

FAA's Determination and Proposed Requirements of the Supplemental NPRM

The changes discussed above expand the scope of the original NPRM; therefore, we have determined that it is necessary to reopen the comment period to provide additional opportunity for public comment on this supplemental NPRM.

Costs of Compliance

The following table provides the estimated costs for U.S. operators to comply with this supplemental NPRM.

Estimated Costs

ActionWork hoursAverage labor rate per hourPartsCost per airplaneNumber of U.S.-registered airplanesFleet cost
General visual inspection, per inspection cycle1$65None$6554$3,510, per inspection cycle.
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Replacement of side brace assemblies2 (1 hour per side brace)65$0130547,020

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.

Regulatory Findings

We have 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 that the 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. 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.

We prepared a regulatory evaluation of the estimated costs to comply with this supplemental NPRM and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation.

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List of Subjects in 14 CFR Part 39

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The Proposed Amendment

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

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PART 39—AIRWORTHINESS DIRECTIVES

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

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

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[Amended]

2. The Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):

Aerospatiale: Docket No. FAA-2005-20220; Directorate Identifier 2004-NM-152-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by January 9, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Aerospatiale Model ATR42-200, -300, and -320 airplanes, certificated in any category; with main landing gear (MLG) side brace assemblies having part number (P/N) D22710000-( ) except -8, equipped with upper arms having P/N D56778-10.

Unsafe Condition

(d) This AD results from an operator who reported experiencing an unlock warning for the MLG on the right side of the airplane. We are issuing this AD to prevent cracking of the upper arms of the side braces of the MLG, which could result in failure of the MLG during landing and possible damage to the airplane and injury to the flightcrew and passengers.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Service Bulletin References

(f) The term “service bulletin,” as used in this AD, means the Accomplishment Instructions of the following service bulletins, as applicable:

(1) For the general visual inspection and ultrasonic inspection specified in paragraphs (g) and (h) of this AD, respectively: Messier-Dowty Special Inspection Service Bulletin 631-32-181, Revision 2, dated June 3, 2005; and

(2) For the replacement specified in paragraph (j) of this AD: Messier-Dowty Service Bulletin 631-32-176, Revision 1, dated June 2, 2004.

Repetitive Inspections of Identification Plates

(g) Within 2 months or 500 flight hours after the effective date of this AD, whichever is first: Do a general visual inspection of the upper arms of the MLG side braces for inadequately bonded identification plates having P/Ns D61565-1, D61566-1, D61567-1, and D61568-1 and for any missing bead of glue, in accordance with the service bulletin. Thereafter at intervals not to exceed 2 months or 500 flight hours, whichever is first: Repeat the inspection of the upper arm of the MLG side brace for any side brace assembly that has not been inspected in accordance with paragraph (h) of this AD or replaced as required by paragraph (j) of this AD.

Note 1:

For the purposes of this AD, a general visual inspection is: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to ensure visual access to all surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”

Ultrasonic Inspection, if Necessary

(h) If any identification plate having P/N D61565-1, D61566-1, D61567-1, or D61568-1 or any bead of glue is missing or found inadequately bonded during any inspection required by paragraph (g) of this AD: Within 25 flight hours since the most recent general visual inspection, do an ultrasonic inspection of the upper arm of the MLG side brace for any defects and do any related investigative and corrective actions as applicable, by doing all of the applicable actions specified in Part B.(3) of the service bulletin; except where the service bulletin specifies replacing the side brace with a side brace equipped with an airworthy upper arm, replace it with a part modified in accordance with paragraph (j) of this AD. Any corrective actions must be done before further flight after doing the ultrasonic inspection. Start Printed Page 73674

Additional Ultrasonic Inspection for Certain Airplanes

(i) For airplanes on which the ultrasonic inspection specified in paragraph (h) of this AD has been accomplished in accordance with Messier-Dowty Special Inspection Service Bulletin 631-32-181, Revision 1, dated March 16, 2005: Within 25 flight hours after the effective date of the AD, do all the applicable actions specified in paragraph (h) of this AD, in accordance with Messier-Dowty Special Inspection Service Bulletin 631-32-181, Revision 2, dated June 3, 2005.

Replacement with a Modified Side Brace Assembly

(j) At the applicable compliance time specified in paragraphs (j)(1) or (j)(2) of this AD: Remove the side brace assembly and replace it with a part modified by doing all of the actions in the service bulletin. Replacement of a side brace assembly with a modified part terminates the repetitive inspections required by paragraph (g) of this AD for that modified side brace assembly only. If the side brace assembly of the left and right MLG is replaced with a modified part, no more work is required by paragraph (g) of this AD.

(1) For airplanes on which Messier-Dowty Service Bulletin 631-32-072 has not been accomplished: Before the accumulation of 15,000 total flight cycles on a side brace assembly since new or since last overhaul, or 96 months on a side brace assembly since new or since last overhaul, whichever is first.

(2) For airplanes on which Messier-Dowty Service Bulletin 631-32-072 has been accomplished: Before the accumulation of 18,000 total flight cycles on a side brace assembly since new or since last overhaul, or 96 months on a side brace assembly since new or since last overhaul, whichever is first.

Credit for Previous Service Bulletin

(k) Replacements done before the effective date of this AD in accordance with Messier-Dowty Service Bulletin 631-32-176, dated February 26, 2004, are acceptable for compliance with the corresponding requirements of paragraph (j) of this AD.

No Reporting Requirement

(l) Although Messier-Dowty Special Inspection Service Bulletin 631-32-181, Revision 2, dated June 3, 2005, specifies to submit certain information to the manufacturer, this AD does not include that requirement.

Alternative Methods of Compliance (AMOCs)

(m)(1) The Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

(2) Before using any AMOC approved in accordance with 14 CFR 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

Related Information

(n) French airworthiness directive F-2005-106, dated July 6, 2005, also addresses the subject of this AD.

Start Signature

Issued in Renton, Washington, on December 6, 2005.

Kevin M. Mullin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. 05-23953 Filed 12-12-05; 8:45 am]

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