04-15790. Airworthiness Directives; Empresa Brasileira de Aeronautica S.A. (EMBRAER) Model EMB-135 and -145 Series 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 certain EMBRAER Model EMB-135 and -145 series airplanes. This proposed AD would require measuring the fillet radius dimension of the trunnion fitting webs of the wings; and reworking the fillet radius of the trunnion fitting web in order to increase the radius, doing related investigative actions, and doing applicable corrective action, if necessary. This proposed AD is prompted by a report indicating that trunnion fittings of the wings have been manufactured with a web fillet radius smaller than the minimum required by the design data, which may induce the occurrence of fatigue cracks at the root of the trunnion fillet radius and adjacent structures (e.g., spar and ribs). We are proposing this AD to detect and correct fatigue cracking of the wing trunnion fittings or adjacent structure, which could result in failure of the main landing gear, consequent damage to surrounding structure, and possible loss of control of the airplane during landing.

DATES:

We must receive comments on this proposed AD by August 12, 2004.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD.

• 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.
• By fax: [phone].
• 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.

You can get the service information identified in this proposed AD from Empresa Brasileira de Aeronautica S.A. (EMBRAER), P.O. Box 343—CEP 12.225, Sao Jose dos Campos—SP, Brazil.

You may examine the contents of this AD docket on the Internet at http://dms.dot.gov,, or at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, on the plaza level of the Nassif Building, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

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

SUPPLEMENTARY INFORMATION:

Docket Management System (DMS)

The FAA has implemented new procedures for maintaining AD dockets electronically. As of May 17, 2004, new AD actions are posted on DMS and assigned a docket number. We track each action and assign a corresponding directorate identifier. The DMS AD docket number is in the form “Docket No. FAA-2004-99999.” The Transport Airplane Directorate identifier is in the form “Directorate Identifier 2004-NM-999-AD.” Each DMS AD docket also lists the directorate identifier (“Old Docket Number”) as a cross-reference for searching purposes.

Comments Invited

We invite you to submit any written relevant data, views, or arguments regarding this proposed AD. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2004-18582; Directorate Identifier 2003-NM-35-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments submitted by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, 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 proposed AD. Using the search function of our docket website, 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.

We are reviewing the writing style we currently use in regulatory documents. We are interested in your comments on whether the style of this document is clear, and your suggestions to improve the clarity of our communications that affect you. You can get more information about plain language at http://www.faa.gov/​language and http://www.plainlanguage.gov.

Examining the Docket

You may examine the AD docket 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 [phone]) is located on the plaza level of the Nassif Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the DMS receives them.

Discussion

The Departmento de Aviacao Civil (DAC), which is the airworthiness authority for Brazil, notified us that an unsafe condition may exist on certain EMBRAER Model EMB-135 and -145 series airplanes. The DAC advises that the trunnion fittings of the wings have been manufactured with a Web fillet radius smaller than the minimum required by the design data. This may induce fatigue cracks at the root of the trunnion fillet radius and adjacent structures (e.g., spar and ribs). Such fatigue cracks, if not detected and corrected, could result in failure of the main landing gears (MLG), consequent damage to surrounding structure, and possible loss of control of the airplane during landing.

Relevant Service Information

EMBRAER has issued Service Bulletin 145-57-0034, Change 01, dated January 9, 2002. The service bulletin describes procedures for measuring the fillet radius dimension of the trunnion fitting webs of the wings; and reworking the fillet radius of the trunnion fitting web in order to increase the radius, doing related investigative actions, and doing applicable corrective actions, if necessary. The related investigative action involves performing a dye-penetrant inspection on the reworked area for cracks. The applicable corrective actions involve contacting EMBRAER for technical disposition. We have determined that accomplishment of the actions specified in the service information will adequately address the unsafe condition. The DAC mandated the service information and issued Brazilian airworthiness directive 2001-12-03R1, effective February 4, 2002, to ensure the continued airworthiness of these airplanes in Brazil.

FAA's Determination and Requirements of the Proposed AD

These airplane models are manufactured in Brazil and are type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the DAC has kept the FAA informed of the situation described above. We have examined the DAC's findings, evaluated all pertinent information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Therefore, we are proposing this AD, which would require measuring the fillet radius dimension of the trunnion fitting webs of the wings; and reworking the fillet radius of the trunnion fitting web in order to increase the radius, doing related investigative actions, and doing applicable corrective actions, if necessary. The proposed AD would require you to use the service information described previously to perform these actions, except as discussed under “Differences Between the Proposed AD and the Service Bulletin.”

Differences Between Proposed AD and Service Bulletin

Operators should note that, although the service bulletin specifies that operators may contact the manufacturer for disposition of certain repair conditions, this proposed AD would require operators to repair those conditions in accordance with a method approved by either the FAA or the DAC (or its delegated agent). In light of the type of repair that would be required to address the unsafe condition, and consistent with existing bilateral airworthiness agreements, we have determined that, for this proposed AD, a repair approved by either the FAA or the DAC would be acceptable for compliance with this proposed AD.

In addition, unlike the procedures described in the service bulletin, this proposed AD would not permit further flight if cracks are detected in the trunnion fitting of the main landing gear. We have determined that, because of the safety implications and consequences associated with such cracking, any cracked trunnion fitting must be repaired before further flight.

Costs of Compliance

This proposed AD would affect about 60 airplanes of U.S. registry. The proposed measurement would take about 2 work hours per airplane, at an average labor rate of $65 per work hour. Based on these figures, the estimated cost of the proposed AD for U.S. operators is $7,800, or $130 per airplane.

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 proposed AD. See the ADDRESSES section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• 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 (AD):

Empresa Brasileira De Aeonautica S.A. (EMBRAER): Docket No. FAA-2004-18582; Directorate Identifier 2003-NM-35-AD.

Comments Due Date

(a) The Federal Aviation Administration must receive comments on this AD action by August 12, 2004.

Affected ADs

(b) None.

Applicability

(c) This AD applies to EMBRAER Model EMB-135 and -145 series airplanes, as listed in EMBRAER Service Bulletin 145-57-0034, Change 01, dated January 9, 2002; certificated in any category.

Unsafe Condition

(d) This AD was prompted by a report indicating that trunnion fittings of the wings have been manufactured with a web fillet radius smaller than the minimum required by the design data, which may induce the occurrence of fatigue cracks at the root of the trunnion fillet radius and adjacent structures (e.g., spar and ribs). We are issuing this AD to detect and correct fatigue cracking of the wing trunnion fittings or adjacent structure, which could result in failure of the main landing gear, consequent damage to surrounding structure, and possible loss of control of the airplane during landing.

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

(f) The term “service bulletin,” as used in this AD, means the Accomplishment Instructions of EMBRAER Service Bulletin 145-57-0034, Change 01, dated January 9, 2002.

Measurement

(g) Before the accumulation of 2,000 total flight cycles, or within 500 flight hours after the effective date of this AD, whichever occurs later, measure the fillet radius dimension of the trunnion fitting webs of the wings in accordance with paragraph 3.(C), “Part I,” of the service bulletin.

(1) If the fillet radius value is equal to or greater than 0.1969 inches (5 mm), no further action is required by this AD.

(2) If a fillet radius value is less than 0.0394 inches (1 mm), before further flight, do the actions specified in paragraph (h) of this AD.

(3) If the fillet radius value is equal to or greater than 0.0394 inch (1 mm), but less than 0.1969 inch (5 mm), before the accumulation of 4,000 total flight cycles, or within 500 flight hours after the effective date of this AD, whichever occurs later, do the actions specified in paragraph (h) of this AD.

Rework and Further Corrective Actions, if Necessary

(h) Rework the fillet radius of the trunnion fitting web to increase the radius, do related investigative actions, and do applicable corrective actions by accomplishing all the actions specified in paragraph 3.(D), “Part II,” of the service bulletin. Do the actions in accordance with the service bulletin, except as provided by paragraph (i) of this AD. Any applicable corrective actions must be done before further flight.

(1) If the final fillet radius is less than 0.1969 inch (5 mm) and the radius limit contour is reached, before further flight, repair in accordance with a method approved by either the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate; or the Departmento de Aviacao Civil (DAC) (or its delegated agent).

(2) If the final fillet radius is equal to or greater than 0.1969 inches (5 mm), before further flight, shot-peen the reworked area in accordance with paragraph 3.(E), “Part III,” of the service bulletin.

(i) If any crack is found in the structure during the related investigative action required by paragraph (h) of this AD, before further flight, repair in accordance with either the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate; or the DAC (or its delegated agent).

Credit for Previous Revisions of Service Bulletin

(j) Except as provided by paragraphs (h)(1) and (i) of this AD, measurements and rework of the fillet radius done before the effective date of this AD in accordance with EMBRAER Service Bulletin 145-57-0034, dated October 11, 2001, are acceptable for compliance with the requirements of this AD.

Alternative Methods of Compliance (AMOC)

(k) The Manager, International Branch, 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.

Related Information

(l) Brazilian airworthiness directive 2001-12-03R1, effective February 4, 2002, also addresses the subject of this AD.

Issued in Renton, Washington, on July 6, 2004.

Kevin M. Mullin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.