AD 97-24-01

This amendment adopts a new airworthiness directive (AD) that is applicable to all Dornier Model 328-100 series airplanes. This action requires repetitive inspections to detect migration or damage of
the bushings of the main landing gear (MLG) trailing arm, and replacement of any damaged or displaced bushing. This amendment is prompted by reports indicating that damagedor displaced bushings have
been found on several MLG trailing arms of Dornier Model 328-100 series airplanes. The actions specified in this AD are intended to prevent failure of the bushings of the MLG trailing arm, which could result in
collapse of the MLG during landing.

Final rule

97-24-01 DORNIER: Amendment 39-10208. Docket 97-NM-284-AD.
Applicability: All Model 328-100 series airplanes, 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 (f) 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 bushings of the main landing gear (MLG) trailing arm, which could result in collapse of the MLG during landing, accomplish the following:

(a) For airplanes that have accumulated 3,000 total flight hours or more as of the effective date of this AD: Within 7 days after the effective date of this AD, conduct an external visual inspection to detect damage or migration of the bushings of each MLG trailing arm, in accordance with Section 2.B(1) of Dornier Alert Service Bulletin ASB-328-32-019, dated September 17, 1997.

(b) For airplanes that have accumulated less than 3,000 total flight hours as of the effective date of this AD: Prior to accumulation of 3,000 total flight hours, or within 300 flight hours after the effective date of this AD, whichever occurs later, conduct a detailed visual inspection to detect damage of the bushings of each MLG trailing arm, in accordance with Section 2.B(2) of Dornier Alert Service Bulletin ASB-328-32-019, dated September 17, 1997.

(c) If no damage or migration is detected during the inspection required by paragraph (a) or (b) of this AD within 300 flight hours after the inspection, and thereafter at intervals not to exceed 300 flight hours, conduct a detailed visual inspection to detect damage of the bushings of each MLG trailing arm, in accordance with Section 2.B(2) of Dornier Alert Service Bulletin ASB-328-32-019, dated September 17, 1997.

(d) If any damage or migration is detected during any inspection required by paragraph (a), (b), or (c) of this AD, prior to further flight, replace any affected bushing in accordance with Section 2.B(2) of Dornier Alert Service Bulletin ASB-328-32-019, dated September 17, 1997. Thereafter, except as provided by paragraph (e) of this AD, continue to inspect the bushings in accordance with paragraph (c) of this AD.

(e) For airplanes on which all bushings of both MLG trailing arms have been replaced in accordance with Dornier Alert Service Bulletin ASB-328-32-019, datedSeptember 17, 1997: Within 3,000 flight hours after replacement of the bushings, and thereafter at intervals not to exceed 300 flight hours, inspect the new bushings in accordance with paragraph (c) of this AD.

(f) 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, FAA, Transport Airplane Directorate. 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 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.

(g) 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.

(h) The inspection and replacement shall be done in accordance with Dornier Alert Service Bulletin ASB-328-32-019, dated September 17, 1997. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Dornier Deutsche Aerospace, P.O. Box 1103, D-82230 Wessling, Federal Republic of Germany. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(i) This amendment becomes effective on December 3, 1997.

The Luftfahrt-Bundesamt (LBA), which is the airworthiness authority for Germany, recently notified the FAA that an unsafe condition may exist on all Dornier Model 328-100 series
airplanes. The LBA advises that fatigue damaged or displaced bushings have been found on several main landing gear (MLG) trailing arms. This condition, if not corrected, could result in collapse of the MLG during
landing.

Explanation of Relevant Service Information

Dornier has issued Alert Service Bulletin ASB-328-32-019, dated September 17, 1997, which describes procedures for repetitive visual inspections to detect damage or migration of the bushings of the MLG trailing arm, and replacement of any damaged or displaced bushing. The LBA advises that it considers this alert service bulletin to be mandatory, and that it is in the process of issuing a German airworthiness directive to assure the continued airworthiness of these airplanes in Germany.

FAA's ConclusionsThis 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 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 is being issued to require accomplishment of the actions specified in the alert service bulletin described previously, except as discussed below.

Differences Between This AD and the Related Service Bulletin

Operators should note that, unlike the procedures described in Dornier Alert Service Bulletin ASB-328-32-019, dated September 17, 1997, this AD does not permit further flight if damage or migration of the bushings is found. The FAA has determined that, because of the safety implications and consequences associated with such damage, any bushing that is found to be damaged or displaced must be replaced prior to further flight.

Interim Action

This AD is considered to be interim action until final action is identified, at which time the FAA may consider additional rulemaking.

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 thatinvolves 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.
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 97-NM-284-AD.'' The postcard will be date stamped and returned to the commenter.

Regulatory Impact

The regulations adopted herein will not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation ofa Federalism Assessment.
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 this emergency 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.

Sec. 39.13 [Amended]

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