Airworthiness Directives; Empresa Brasileira de Aeronautica S.A. (EMBRAER) Model EMB-120 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain EMBRAER Model EMB-120 series airplanes. This proposal would require repetitive inspections for cracks or evidence of damage/distortion of the anti-skid drive coupling clips for the hubcaps of the main landing gear (MLG) wheels; repetitive measurement of the gap and height dimensions of the coupling clips; corrective actions, if necessary; and eventual replacement of all coupling clips with new, improved coupling clips. This action is necessary to prevent excessive gaps in the anti-skid drive coupling clips for the hubcaps of the MLG, which could result in momentary loss of the normal braking system at low speeds, and reduced controllability of the airplane. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by May 6, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-79-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 (425) 227-1232. Comments may also be sent via the Internet using the following address: 9-anm-nprmcomment@faa.gov. Comments sent via fax or the Internet must contain “Docket No. 2003-NM-79-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 (425) 227-2125; fax (425) 227-1149.

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-79-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-79-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The Departmento de Aviacao Civil (DAC), which is the airworthiness authority for Brazil, notified the FAA that an unsafe condition may exist on certain EMBRAER Model EMB-120 series airplanes. The DAC advises that it received reports of momentary loss of normal braking during low speed taxiing. In two of the reported incidents there was a complete loss of normal braking in all four main landing gear (MLG) wheels. Investigation revealed an excessive gap in the anti-skid drive coupling clips for the hubcaps of the inboard and outboard MLG wheels. These excessive gaps may impair the proper coupling of the clips with the anti-skid wheel speed transducer shaft, causing a temporary loss of normal braking in all four main wheels. This condition, if not corrected, could result in momentary loss of the normal braking system at low speeds and reduced controllability of the airplane.

Explanation of Relevant Service Information

EMBRAER has issued Service Bulletin 120-32-0088, Revision 01, dated October 1, 2003, which describes procedures for the following actions:

• A visual inspection for cracks, damage, distortion or broken-off pieces of the anti-skid drive coupling clips for the hubcaps of the inboard and MLG wheels.
• Measurement of the “G” (gap) and “H” (height) dimensions of the coupling clips to ensure they are within the tolerances specified in Figure 1 of the service bulletin; and repetitive measurement of dimension “G” at every wheel or transducer change.
• For certain airplanes, a one-time re-inspection of the anti-skid drive coupling clips for the affected MLG wheel hubcap at the next MLG wheel change, per Part II of the service bulletin.

The service bulletin also describes procedures for the following corrective actions:

• Replacement of any coupling clip having evidence of cracks, damage, distortion, or broken-off pieces; or having a measurement of dimension “H” that is outside the specified tolerance; with a new, improved part.
• Adjustment of any clip with dimension “G” outside the specified tolerance.
• Replacement of any clip where dimension “G” cannot be adjusted to the specified tolerance.
• Eventual replacement of all coupling clips with new, improved clips at the next C-check.

Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition. The DAC classified this service bulletin as mandatory and issued Brazilian airworthiness directive 2003-01-01, dated February 6, 2003, to ensure the continued airworthiness of these airplanes in Brazil.

FAA's Conclusions

This airplane model is manufactured in Brazil and is 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 us informed of the situation described above. We have examined the findings of the DAC, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Explanation of Requirements of Proposed AD

Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design registered in the United States, the proposed AD would require accomplishment of the actions specified in the service bulletin described previously, except as discussed below.

Difference Between the Brazilian Airworthiness Directive, the Service Bulletin, and the Proposed AD

Paragraph (c) of the Brazilian airworthiness directive recommends that no later than March 30, 2003, the installation procedures for the MLG be revised to include a mandatory visual inspection for cracks, evident damage, distortion or broken-off pieces, of the anti-skid drive coupling clips for the MLG wheel hubcap; and a complete clip dimensional verification including the gap and the height. This proposed AD does not include a requirement to revise the installation procedures for the MLG wheels. However, paragraph (a) of this proposed AD does require repetitive general visual inspections and repetitive measurements of dimensions “G” and “H” of the anti-skid drive coupling at every wheel change or wheel speed transducer change.

The service bulletin states that if the measurement of dimension “G” of any anti-skid drive coupling clip is out of the tolerance specified in the service bulletin, and the clip can be adjusted to the specified tolerance, one re-inspection is necessary at the next MLG wheel change per Part II of the service bulletin. The service bulletin also contains a note stating that dimension “G” should be checked at every wheel or transducer change. This proposed AD does not include such a requirement; however, as previously mentioned, paragraph (a) of this proposed AD does require repetitive measurements of dimensions “G” and “H” of the anti-skid drive coupling at every wheel change or wheel speed transducer change.

Clarification of Inspection Terminology

The service bulletin specifies a visual inspection of the MLG wheel hubcap clips for cracks, evident damage, distortion, or broken-off pieces. This proposed AD requires a general visual inspection. A note has been added to define that inspection.

Cost Impact

We estimate that 220 airplanes of U.S. registry would be affected by this proposed AD.

It would take approximately 2 work hours per airplane to do the proposed general visual inspection and measurement of dimensions “G” and “H”, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of the proposed actions on U.S. operators is estimated to be $28,600, or $130 per airplane, per inspection cycle.

It would take approximately 1 work hour per airplane to do the proposed replacement of the coupling clips, at an average labor rate of $65 per work hour. Required parts would cost approximately $600 per airplane. Based on these figures, the cost impact of the proposed action on U.S. operators is estimated to be $146,300, or $665 per airplane.

The cost impact figures discussed above are 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.