04-16681. Airworthiness Directives; Empresa Brasileira de Aeronautica S.A. (EMBRAER) Model EMB-135 and EMB-145 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Supplemental notice of proposed rulemaking; reopening of comment period.

SUMMARY:

This document revises an earlier proposed airworthiness directive (AD), applicable to certain EMBRAER Model EMB-135 and EMB-145 series airplanes, that would have required inspection of the housings of the main landing gear (MLG) leg strut bushings; repair of the housings if necessary; and replacement of the MLG leg strut bushings with new bushings. This new action revises the proposed rule by requiring inspection of additional MLG leg strut bushings; removing the requirement to replace the MLG leg strut bushings; and clarifying that related investigative and corrective actions must be accomplished. The actions specified by this new proposed AD are intended to prevent corrosion of the housings of the MLG leg strut bushings and consequent failure of the MLG. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by August 16, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-85-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to [phone]. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via fax or the Internet must contain “Docket No. 2003-NM-85-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 or 2000 or ASCII text.

The service information referenced in the proposed rule may be obtained from Empresa Brasileira de Aeronautica S.A. (EMBRAER), P.O. Box 343—CEP 12.225, Sao Jose dos Campos—SP, Brazil. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT:

Dan Rodina, Aerospace Engineer; International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this action may be changed in light of the comments received.

Submit comments using the following format:

• Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
• For each issue, state what specific change to the proposed AD is being requested.
• Include justification (e.g., reasons or data) for each request.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2003-NM-85-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-85-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to add an airworthiness directive (AD), applicable to certain EMBRAER Model EMB-135 and EMB-145 series airplanes, was published as a notice of proposed rulemaking (NPRM) in the Federal Register on December 31, 2003 (68 FR 75468). That NPRM would have required inspection of the housings of the main landing gear (MLG) leg strut bushings; repair of the housings if necessary; and replacement of the MLG leg strut bushings with new bushings. That NPRM was prompted by a report that corrosion was discovered on the housings of certain MLG leg strut bushings due to water accumulation in the holes of those bushings. That condition, if not corrected, could result in failure of the MLG.

Explanation of New Relevant Service Information

Since the issuance of the original NPRM, EMBRAER has issued Service Bulletin 145-32-0066, Change 03, dated April 19, 2004. (The original NPRM refers to Change 01 of that service bulletin, dated August 15, 2002, as the appropriate source of service information for the proposed actions.) Change 03 of the service bulletin identifies additional part numbers and serial numbers of MLG leg struts that are affected by that service bulletin. Change 03 of the service bulletin describes procedures for an inspection for corrosion of the housings of the MLG leg strut bushings; and related investigative and corrective actions; which are similar to those described in Change 01 of the service bulletin. The procedures for investigative and corrective actions include removing any corrosion; enlarging the diameter of the bushing housing, if necessary; performing a dye-penetrant inspection of the housings for further sign of corrosion, if necessary; reworking and installing the bushings; and applying corrosion-inhibiting compound to the bushing housings. The Departmento de Aviacao Civil, which is the airworthiness authority for Brazil, has approved this service bulletin.

EMBRAER Service Bulletin 145-32-0066, Change 03, refers to Embraer Liebherr Equipamentos do Brasil S.A. (ELEB) Service Bulletin 2309-2006-32-01, Revision 03, dated April 19, 2004, as an additional source of service information for the inspection and repair of the MLG leg strut bushings. The ELEB service bulletin is included within the EMBRAER service bulletin.

Comments

Interested persons have been afforded an opportunity to participate in the making of this amendment. The FAA has duly considered the comments received.

Request To Revise Applicability Statement

Several commenters request that we revise the applicability statement of the original NPRM to eliminate certain airplane serial numbers. The commenters note that defining the applicability in terms of installed MLG leg strut part numbers results in airplanes that are not affected by the original NPRM being included in the applicability. The commenters point out that the bushing housings on certain airplane serial numbers have already received corrosion protection, and thus should not be subject to the proposed actions. Other airplane serial numbers have received, in production, a modification equivalent to that in EMBRAER Service Bulletin 145-32-0066, Change 01.

We partially agree with the commenters' requests. We agree to revise the manner in which the applicability is stated in this supplemental NPRM, so that it more closely matches the effectivity of the service bulletin. Thus, instead of listing the affected MLG leg strut part numbers, the applicability statement of this supplemental NPRM refers to the table under the heading “Affected component” in paragraph 1.B., “Effectivity,” of EMBRAER Service Bulletin 145-32-0066, Change 03, as the source for affected MLG leg strut part and serial numbers.

However, we do not agree to revise the applicability statement to exclude certain airplane serial numbers. The service bulletin notes that the MLG leg struts are line replaceable units. Thus, an affected MLG leg strut may have been removed from the airplane on which it was delivered and subsequently installed on an airplane outside the serial number range specified in the service bulletin.

Request To Remove Replacement Requirement

One commenter, the airplane manufacturer, requests that we remove the requirement to replace the MLG leg strut bushings, which is specified in paragraph (b) of the original NPRM. The commenter states that the new bushings are not necessary to prevent corrosion because, although water can accumulate in the holes of the leg strut bushings, the primary cause of the unsafe condition is lack of corrosion protection in the housings. Thus, the application of corrosion protection in the housings, as described in the service bulletin, eliminates the need to replace the bushings. We concur and have omitted paragraph (b) of the original NPRM from this supplemental NPRM.

Request To Provide Credit for Actions Accomplished Previously

One commenter requests that we revise the original NPRM to give credit for accomplishment of the proposed actions per EMBRAER Service Bulletin 145-32-0066, dated January 8, 2002.

We concur. We have reviewed the original issue of the service bulletin and find that the procedures therein are substantively similar to those in Change 01. Accordingly, we have added a new paragraph (b) to this supplemental NPRM to give credit for actions accomplished before the effective date of the AD per the original issue, Change 01, or Change 02 of the service bulletin. (As explained previously, paragraph (b) of the original NPRM has been omitted from this supplemental NPRM. Thus, adding a new paragraph (b) does not necessitate the re-identification of subsequent paragraphs.)

Explanation of Additional Change to Original NPRM

We have revised paragraph (a) of the original NPRM to clarify that, if no corrosion is found, all applicable actions specified in the service bulletin (e.g., applying corrosion-inhibiting compound) must be done to comply with the intent of the proposed AD.

We have also revised the estimated number of work hours stated in the Cost Impact section of this supplemental NPRM from 7 to 14, to reflect the estimate contained in the EMBRAER service bulletin.

Conclusion

Since certain changes described previously expand the scope of the originally proposed rule, we have determined that it is necessary to reopen the comment period to provide additional opportunity for public comment.

Cost Impact

We estimate that 75 airplanes of U.S. registry would be affected by this proposed AD.

It would take approximately 14 work hours per airplane to accomplish the proposed inspection of the bushing housings for corrosion, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of the proposed inspection on U.S. operators is estimated to be $68,250, or $910 per airplane.

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.

Regulatory Impact

The regulations proposed herein 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. Therefore, it is determined that this proposal would not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that this proposed regulation (1) is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39—AIRWORTHINESS DIRECTIVES

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. Section 39.13 is amended by adding the following new airworthiness directive:

Empresa Brasileira De Aeronautica S.A. (EMBRAER): Docket 2003-NM-85-AD.

Applicability: Model EMB-135 and EMB-145 series airplanes, certificated in any category, equipped with a main landing gear (MLG) leg strut having a part number (P/N) and serial number (S/N) listed in the table under the heading “Affected component” in paragraph 1.B., “Effectivity,” of EMBRAER Service Bulletin 145-32-0066, Change 03, dated April 19, 2004.

Compliance: Required as indicated, unless accomplished previously.

To prevent corrosion of the housings of the main landing gear (MLG) leg strut bushings and consequent failure of the MLG, accomplish the following:

Inspection and Investigative and Corrective Actions

(a) Within 5,500 flight hours after the effective date of this AD, perform a detailed inspection of the housings of the MLG leg strut bushings for corrosion per the Accomplishment Instructions of EMBRAER Service Bulletin 145-32-0066, Change 03, dated April 19, 2004.

(1) If no corrosion is found, before further flight, do all applicable actions in and per the Accomplishment Instructions of the service bulletin.

(2) If any corrosion is found, before further flight, do all applicable investigative and corrective actions in and per the Accomplishment Instructions of the service bulletin.

Note 1:

For the purposes of this AD, a detailed inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”

Note 2:

EMBRAER Service Bulletin 145-32-0066, Change 03, dated April 19, 2004, refers to Embraer Liebherr Equipamentos do Brasil S.A. (ELEB) Service Bulletin 2309-2006-32-01, Revision 03, dated April 19, 2004, as an additional source of service information for the inspection and repair of the MLG leg strut bushings. The ELEB service bulletin is included within the EMBRAER service bulletin.

Inspections Accomplished Per Previous Issue of Service Bulletin

(b) Inspections and related investigative and corrective actions, accomplished before the effective date of this AD per EMBRAER Service Bulletin 145-32-0066, dated January 8, 2002; Change 01, dated August 15, 2002; or Change 02, dated February 26, 2004; are considered acceptable for compliance with the corresponding action specified in this AD.

Alternative Methods of Compliance

(c) In accordance with 14 CFR 39.19, the Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA, is authorized to approve alternative methods of compliance for this AD.

Note 3:

The subject of this AD is addressed in Brazilian airworthiness directive 2002-12-01, effective January 6, 2003.

Issued in Renton, Washington, on July 9, 2004.

Kevin M. Mullin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.