On February 15, 2000, the FAA issued AD 2000-04-09, amendment 39-11591 (65 FR 9217, February 24, 1000), applicable to certain EMBRAER Model EMB-135 and EMB-145 series airplanes, to require various inspections to detect discrepancies of the elevator servo tab and spring tab hinge fittings of the horizontal stabilizer, and follow-on corrective actions, if necessary. That action was prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions required by that AD are intended to prevent the linkage of the elevator servo tab or spring tab hinge fittings from separating from the horizontal stabilizer, which could result in loss of control of the airplane.
Actions Since Issuance of Previous Rule
Since the issuance of that AD, the Departmento de Aviacao Civil (DAC), which is the airworthiness authority for Brazil, has received new information regarding the corrective action necessary to address this unsafe condition. As a result, the DAC has issued the following Brazilian airworthiness directives:
1999-09-01R2, dated May 1, 2000, supersedes Brazilian airworthiness directive 1999-09-01R1, dated October 25, 1999. This new revision was issued to specify repetitive inspection intervals and final rework of certain components. Part III of this revision specifies that, for certain Model EMB-135 and EMB-145 series airplanes, certain modifications of the elevator mass balance assembly and control column nose-up spring modifications, in accordance with Embraer Service Bulletin (S.B.) 145-27-0034, must be completed before accomplishment of the rework specified in Part III of S.B. 145-55-0022, Change 01, dated January 25, 2000.
2000-05-01, dated May 25, 2000, corrects any possible misinterpretation of the replacement procedures included in Brazilian airworthiness directive 1999-09-01R2, and in alert S.B. 145-55-A022 and S.B. 145-55-0022.
Reports indicated that loose hinge fittings were found, which was attributed to the incorrect application of the attachment fasteners to the tab upper skin. It is considered that the loss of fitting rigidity could cause damage to the other fasteners in the tab spar. Reports also indicated that some of the fasteners (which attach the spring-tab actuating arm to the tab upper skin and the servo-tab actuating linkage hinge to the tab lower skin) were not replaced with fasteners having a washer, because the collar conformation of those fasteners was found to be correct. In addition, maintenance records revealed that such fasteners may not have been replaced on certain airplanes. As a result of these findings, the DAC issued the previously referenced Brazilian airworthiness directives to clarify that all attachment fasteners must be installed with a washer, and that the fasteners must be replaced independently of the installation condition (even if the collar conformation is found to be "correct"). FAA's
Conclusions
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. The FAA has 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 Relevant Service Information
Embraer has issued the following service information:
Service Bulletin 145-55-0022, Change 02, dated May 4, 2000, adds a fiberscopic inspection in Part II of the Accomplishment Instructions to detect the presence of a washer; and installation of a washer, if necessary. Part III of this service bulletin revises certain rework procedures (including rework and installation of the elevator servo and spring tabs; and reidentification, static balancing, and installation of the elevator). This rework procedure also specifies that, for certain airplanes, the modification specified by Embraer S.B. 145-27-0034 must be accomplished before Part III of S.B. 145-55-0022, Change 02, is accomplished. Accomplishment of the actions specified in Part III of S.B. 145-55-0022, Change 02, eliminates the need for the repetitive inspections.
Service Bulletin 145-55-0024, dated May 25, 2000, adds a fiberscopic inspection of the attachment of the servo tab center hinge fitting to the tab skin in Part II of the Accomplishment Instructions of this service bulletin. This inspection specifies detecting the presence of washers under the collar bases of both attaching fasteners, in the inner side of the tab skin; and corrective actions, if necessary. Procedures include additional action to clarify certain replacement procedures that were specified inalert S.B. 145-55-A022, Change 01, dated October 7, 1999, and Change 02, dated October 8, 1999. Such action specifies that any discrepant fastener must be replaced with a new fastener having a washer, and that the action if required to be accomplished independently of the installation condition. In addition, S.B. 145-55-0024 specifies that operators report any discrepancy found during inspections of elevator spring tab and servo tab hinge fittings that are specified in Part I of the Accomplishment Instructions of the service bulletin.
Service Bulletin 145-27-0034, Change 01, dated August 5, 1998, revises procedures for replacing the elevator mass-balance weight assembly and nose-up spring. Procedures also revise static balancing and weight and balance, add new mass-balance weight and its attachment bolt, and delete the instruction for checking the backlash.
The DAC mandated compliance with the preceding service bulletins, and issued previously referenced Brazilian airworthiness directive 1999-09-01R2 in order to assure the continued airworthiness of these airplanes in Brazil.
Explanation of Requirements of Rule
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, this AD supersedes AD 2000-04-09 to continue to require various inspections to detect discrepancies of the elevator servo tab and spring tab hinge fittings of the horizontal stabilizer, and follow-on corrective actions, if necessary. This amendment clarifies certain fiberscopic inspection and replacement procedures, and corrective actions; revises the applicability of the existing AD; and adds an inspection procedure for the servo tab center hinge fittings to detect the presence of washers for both attaching fasteners, and follow-on corrective actions. This amendment also provides for optional terminating action for the repetitive inspections. In addition, this amendment requires that operators report to the manufacturer any discrepancy found during any detailed visual inspection accomplished in accordance with S.B. 145-55-0024, dated May 25, 2000. This AD requires accomplishment of actions specified in the service bulletin described previously, except as discussed below.
Differences Between This AD, Brazilian Airworthiness Directives, and Related Service Information
Operators should note that, although the previously referenced Brazilian airworthiness directives and Embraer service information specify that certain rework actions are required, this AD provides those actions as optional. The FAA has determined that such action may be required in subsequent rulemaking action to provide sufficient time for public comment.
Explanation of Changes to the Applicability of AD 2000-04-09
The applicability of AD 2000-04-09 included all of the serial numbers for Model EMB-135 and EMB-145 series airplanes, as listed in alert S.B. 145-55-A022, Change 02, dated October 8, 1999. However, this AD revises the applicability of this AD to those airplanes listed in S.B. 145-55-0022, Change 02, dated May 4, 2000, or S.B. 145-55-0024, dated May 25, 2000, and those airplanes on which the elevator servo tabs and spring tabs have been replaced in accordance with alert S.B. 145-55-A022, Change 02, dated October 8, 1999, or S.B. 145-55-0022, Change 01, dated January 25, 2000.
Interim Action
This AD is considered to be interim action. The FAA is currently considering requiring the rework of all elevator servo and spring tabs, which will constitute terminating action for the repetitive inspections required by this AD action. However, such action will be proposed in a separate rulemaking action since the compliance time for the rework is sufficiently long so that notice and opportunity for prior public comment will be practicable.
Determination of Rule's Effective Date
Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.
Comments Invited
Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this 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 under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed. 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 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 rule that might suggest a need to modify the 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 that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 2000-NM-204-AD." The postcard will be date stamped and returned to the commenter.
Regulatory Impact
The regulations adopted herein will 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 final rule does not have federalism implications under Executive Order 13132.
The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that thisemergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES."
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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 removing amendment 39-11591 (65 FR 9217, February 24, 2000), and by adding a new airworthiness directive (AD), amendment 39-11956, to read as follows: