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Proposed Rule

Airworthiness Directives; Dornier Model 328-300 Series 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.

Start Preamble

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 Dornier Model 328-300 series airplanes. This proposal would require, for certain airplanes, a one-time torque test (inspection) of the attachment bolts of the forward engine mount vibration isolators to determine if the bolts are adequately torqued, and corrective action, if necessary. For all airplanes, this proposal would prohibit installation of an attachment bolt on the forward engine mount vibration isolators, unless the attachment bolt is torqued within certain limits. These actions are necessary to prevent failure of the engine mount, which could result in separation of the engine from the airplane. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by October 15, 2001.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-174-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. 2001-NM-174-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 for Windows or ASCII text.

The service information referenced in the proposed rule may be obtained from Fairchild Dornier, Dornier Luftfahrt GmbH, P.O. Box 1103, D-82230 Wessling, Germany. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Tom Groves, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-1503; fax (425) 227-1149.

End Further Info End Preamble Start Supplemental Information

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 2001-NM-174-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. 2001-NM-174-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The Luftfahrt-Bundesamt (LBA), which is the airworthiness authority for Germany, notified the FAA that an unsafe condition may exist on certain Dornier Model 328-300 series airplanes. The LBA advises that, during an engine replacement, it was discovered that a certain section of the Aircraft Maintenance Manual (AMM) provides incorrect torque values for the attachment bolts of the forward engine mount vibration isolators. Because this discrepancy exists in the AMM, it is probable that any airplane on which a forward engine mount has been removed or replaced since the airplane was manufactured has attachment bolts that have been inadequately torqued. This condition, if not corrected, could result in failure of the engine mount, which could result in separation of the engine from the airplane.

Explanation of Relevant Service Information

Dornier has issued Service Bulletin SB-328J-71-109, dated March 26, 2001, including Aircraft Maintenance Manual Start Printed Page 47902(AMM) Temporary Revision (TR) 71-130, dated March 8, 2001. The service bulletin describes procedures for a one-time torque test (which the service bulletin refers to as an inspection) of the attachment bolts of the forward engine mount vibration isolators on the left- and right-hand sides of the airplane, to determine if the bolts are adequately torqued, and corrective action, if necessary. If any bolt on a vibration isolator is inadequately torqued, the corrective action involves replacing all bolts on the affected isolator. Procedures for such replacement include performing a visual inspection to determine the condition of components of the vibration isolator, removing the existing bolts and washers that attach the forward engine mount vibration isolators to the engine, installing new bolts to reattach the forward engine mount vibration isolators to the engine, and torquing the new bolts to adequate torque values. Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition.

The LBA classified this service bulletin as mandatory and issued German airworthiness directive 2001-163, dated June 14, 2001, in order to assure the continued airworthiness of these airplanes in Germany.

For the convenience of operators, the service bulletin includes TR 71-130, dated March 8, 2001, which includes revised torque values for the attachment bolts of the forward engine mount vibration isolators.

FAA's Conclusions

This airplane model is manufactured in Germany 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 LBA has kept the FAA informed of the situation described above. The FAA has examined the findings of the LBA, 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 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, the proposed AD would require, for certain airplanes, accomplishment of the actions specified in the service bulletin described previously, except as discussed below. For all airplanes, the proposed AD would prohibit installation of an attachment bolt on the forward engine mount vibration isolators, unless the attachment bolt is torqued within certain limits.

Difference Between This Proposed AD and the Foreign AD

The foreign AD specifies a compliance time of 2,500 flight cycles after the first removal or reinstallation of the forward engine mount vibration isolator for the inspection of the attachment bolts of the forward engine mount vibration isolators to determine if the bolts are adequately torqued, and corrective action, if necessary. The FAA finds that, since some airplanes may have already passed this threshold, it is necessary to allow a grace period for compliance with this proposed AD, so that no airplane will be grounded upon the effective date of the AD. Therefore, this proposed AD would require accomplishment of the proposed actions within 2,500 flight cycles after the first removal or reinstallation of the forward engine mount vibration isolator, or within 30 days after the effective date of this AD, whichever comes later.

Difference Between This Proposed AD and the Service Bulletin

As part of the corrective actions for any inadequately torqued bolt on a vibration isolator, the service bulletin specifies a visual inspection to determine the condition of components of the vibration isolator. However, the service bulletin does not specifically state what type of visual inspection must be done or what corrective actions must be done if any components of the vibration isolator are damaged. Review of Aircraft Maintenance Manual Job Instruction Card 71-20-00, which the service bulletin refers to as an additional source of service information for accomplishment of this inspection, show that a detailed visual inspection and replacement of any damaged vibration isolator component with a new component is necessary. Therefore, paragraph (b) of this proposed AD clarifies that the procedures for replacement of the attachment bolts for the vibration isolator include a detailed visual inspection to determine the condition of vibration isolator components and replacement of any damaged components with new ones. Also, Note 2 of the proposed AD defines a detailed visual inspection.

Cost Impact

The FAA estimates that 36 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 2 work hours per airplane to accomplish the proposed actions, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $4,320, or $120 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 proposed 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.

Start List of Subjects

List of Subjects in 14 CFR Part 39

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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:

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PART 39—AIRWORTHINESS DIRECTIVES

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

Start Authority

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

End Authority
[Amended]

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

Dornier Luftfahrt GMBH: Docket 2001-NM-174-AD.

Applicability: Model 328-300 series airplanes, on which a forward engine mount vibration isolator has been removed or reinstalled since the date of manufacture of the airplane, certificated in any category.

Note 1:

This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been otherwise modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (d) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent failure of the engine mount, which could result in separation of the engine from the airplane, accomplish the following:

One-Time Inspection

(a) For airplanes on which a forward engine mount vibration isolator has been removed or reinstalled prior to the effective date of this AD: Within 2,500 flight cycles after the first removal or reinstallation of a forward engine mount vibration isolator, or within 30 days after the effective date of this AD, whichever comes later, do a one-time torque test (inspection) of the attachment bolts of the forward engine mount vibration isolators on the left- and right-hand sides of the airplane to determine if the bolts are adequately torqued, according to Dornier Service Bulletin SB-328J-71-109, dated March 26, 2001, including Aircraft Maintenance Manual (AMM) Temporary Revision (TR) 71-130, dated March 8, 2001.

Replacement of Bolts

(b) During the inspection required by paragraph (a) of this AD, if the torque value of any attachment bolt is found to be outside the limits specified in Dornier Service Bulletin SB-328J-71-109, dated March 26, 2001, including AMM TR 71-130, dated March 8, 2001: Before further flight, do all actions associated with replacing all bolts on the vibration isolator on which the improperly torqued bolt was found (including performing a detailed visual inspection to determine the condition of components of the vibration isolator and replacement of any damaged components with new components, removing the existing bolts and washers that attach the forward engine mount vibration isolators to the engine, installing new bolts to reattach the forward engine mount vibration isolators to the engine, and torquing the new bolts to adequate torque values), according to the service bulletin.

Note 2:

For the purposes of this AD, a detailed visual 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.”

Torque Requirements

(c) For all airplanes: As of the effective date of this AD, no one may install an attachment bolt on the forward engine mount vibration isolators on any airplane, unless the attachment bolt is torqued within the limits specified in Dornier 328-300 AMM TR 71-130, dated March 8, 2001.

Alternative Methods of Compliance

(d) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, International Branch, ANM-116.

Note 3:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.

Special Flight Permits

(e) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

Note 4:

The subject of this AD is addressed in German airworthiness directive 2001-163, dated June 14, 2001.

Start Signature

Issued in Renton, Washington, on September 7, 2001.

Vi L. Lipski,

Manager, Transport Airplane Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. 01-23070 Filed 9-13-01; 8:45 am]

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