AD 2000-04-23

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Dornier Model 328-100 and -300 series airplanes. This action requires repetitive inspections to detect cracking of the trailing edge of the rudder spring tab, and follow-on actions, if necessary. For certain airplanes, this action provides for optional terminating action for the repetitive inspections. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified in this AD are intended to prevent cracking of the rudder spring tab, which could result in reduced flutter margin and consequent loss of control of the airplane.

Final rule; request for comments

2000-04-23 DORNIER LUFTFAHRT GMBH: Amendment 39-11606. Docket 2000-NM-59-AD.

Applicability: Model 328-100 series airplanes, serial numbers 3005 through 3119 inclusive; and Model 328-300 series airplanes, serial numbers 3108 through 3123 inclusive, and 3125 through 3128 inclusive; certificated in any category.

NOTE 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been 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 (e) 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 cracking of the rudder spring tab, which could result in reduced flutter margin and consequent loss of control of the airplane, accomplish the following:

Initial Inspection
(a) Within 14 days after the effective date of this AD, perform a detailed visual inspection to detect cracking of the trailing edge of the rudder spring tab, in accordance with Figure 1 of Dornier Alert Service Bulletin ASB-328-55-028 (for Model 328-100 series airplanes) or ASB-328J-55-002 (for Model 328-300 series airplanes), both dated October 29, 1999; as applicable.

(1) If no crack is detected, accomplish the actions specified by paragraphs (a)(1)(i) and (a)(1)(ii) of this AD.

(i) Prior to further flight, install high-speed tape on the trailing edge, in accordance with the applicable alert service bulletin.

(ii) Within 60 flight hours or15 days after installation of the tape, whichever occurs first, perform a general visual inspection to detect discrepancies of the tape (including improper seat and damage), in accordance with the applicable alert service bulletin.

(A) If no discrepancy is found, repeat the general visual inspection of the tape thereafter at intervals not to exceed 60 flight hours or 15 days, whichever occurs first, until the requirements of paragraph (b) of this AD have been accomplished.

(B) If any discrepancy is found, prior to further flight, replace the tape with new tape, and repeat the general visual inspection of the tape thereafter at intervals not to exceed 60 flight hours or 15 days, whichever occurs first, until the requirements of paragraph (b) of this AD have been accomplished.

(2) If any crack is detected, prior to further flight, replace the spring tab with a new spring tab, in accordance with the applicable alert 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."

NOTE 3: For the purposes of this AD, a general visual inspection is defined as: "A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or drop-light, and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked."

RepetitiveInspection
(b) Within 400 flight hours after the effective date of this AD; or within 400 flight hours after tab replacement in accordance with paragraph (a)(2) of this AD, if required; whichever occurs later: Perform a detailed visual inspection to detect cracking of the trailing edge of the rudder spring tab, in accordance with Figure 2 of Dornier Alert Service Bulletin ASB-328-55-028 (for Model 328-100 series airplanes) or ASB-328J-55-002 (for Model 328-300 series airplanes), both dated October 29, 1999; as applicable. Accomplishment of the requirements of this paragraph within the compliance time required for paragraph (a) of this AD constitutes terminating action for the requirements of paragraph (a) of this AD.

(1) If no crack is detected, repeat the detailed visual inspection required by paragraph (b) of this AD at intervals not to exceed 400 flight hours.

(2) If any crack is detected, prior to further flight, replace the spring tab with a new spring tab, in accordance with the applicable alert service bulletin. Thereafter, repeat the detailed visual inspection required by paragraph (b) of this AD at intervals not to exceed 400 flight hours.

Optional Terminating Action
(c) For Model 328-100 series airplanes: Accomplishment of the pressure test inspection of the spring tab, and applicable corrective actions, in accordance with Dornier Service Bulletin SB-328-55-307, dated December 1, 1999, constitutes terminating action for the requirements of paragraphs (a) and (b) of this AD.

Spares
(d) As of the effective date of this AD, no person shall install on any airplane a spring tab, part number (P/N) 001A554A1706-000 (for Model 328-100 series airplanes) or P/N 001A554A1706-000 (for Model 328-300 series airplanes), unless that spring tab has been inspected in accordance with the requirements of this AD.

Alternative Methods of Compliance
(e) 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 4: 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
(f) 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.

Incorporation by Reference
(g) The actions shall be done in accordance with Dornier Alert Service Bulletin ASB-328-55-028 (for Model 328-100 series airplanes), dated October 29, 1999; or Dornier Alert Service Bulletin ASB-328J-55-002 (for Model 328-300 series airplanes), dated October 29, 1999. 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 FAIRCHILD DORNIER, DORNIER Luftfahrt GmbH, P.O. Box 1103, D-82230 Wessling, 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.

NOTE 5: The subject of this AD is addressed in German airworthiness directives 2000-002 (for Model 328-100 series airplanes) and 2000-001 (for Model 328-300 series airplanes), both dated January 13, 2000.

(h) This amendment becomes effective on March 22, 2000.

The Luftfahrt-Bundesamt (LBA), which is the airworthiness authority for Germany, notified the FAA that an unsafe condition may exist on certain Dornier Model 328-100 and -300 series airplanes. The LBA advises that it has received a report of 14 cracked rudder spring tabs found during production. Investigation conducted by the manufacturer revealed that the source of the cracks was the shape of the spring tab mold. When the mold was closed during production, layers of the spring tab at the trailing edge were partially exposed and subsequently improperly ground off in the paint shop, destroying one or more layers of the trailing edge. Further investigation by the manufacturer indicated that a spring tab having a crack longer than 750 millimeters would have so little stiffness that the spring tab could flutter. This condition, if not corrected, could result in loss of control of the airplane.

Explanation of Relevant Service Information
Dornier hasissued Alert Service Bulletins ASB-328-55-028 (for Model 328-100 series airplanes) and ASB-328J-55-002 (for Model 328-300 series airplanes), both dated October 29, 1999. These alert service bulletins describe procedures for an initial detailed visual inspection to detect cracking of a 2-inch length of the trailing edge of the rudder spring tab. Follow-on actions for a crack-free spring tab include the installation of high-speed tape on the trailing edge, repetitive visual checks of the tape to detect discrepancies (improper seat and damage), and replacement of discrepant tape with new tape. Corrective actions for a cracked spring tab include replacement with a new spring tab. These alert service bulletins further describe procedures for subsequent, more extensive, repetitive detailed visual inspections to detect cracking of the trailing edge of the rudder spring tab, and replacement of any cracked spring tab with a new spring tab.

The LBA classified these service bulletins as mandatory and issued German airworthiness directives 2000-002 (for Model 328-100 series airplanes) and 2000-001 (for Model 328-300 series airplanes), both dated January 13, 2000, in order to ensure the continued airworthiness of these airplanes in Germany.

Dornier has also issued Service Bulletin SB-328-55-307, dated December 1, 1999, which describes procedures for a one-time pressure test inspection, and permanent repair of any cracked spring tab. Accomplishment of these actions would eliminate the need for the repetitive inspections specified by Dornier Alert Service Bulletin ASB-328-55-028.

FAA's Conclusions
These airplane models are manufactured in Germany 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 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 prevent cracking of the rudder spring tab, which could result in reduced flutter margin and consequent reduced structural integrity and loss of control of the airplane. This AD requires accomplishment of the actions specified in the alert service bulletins described previously, except as discussed below. For Model 328-100 series airplanes, this AD also provides for an optional repair, which, if accomplished, would terminate the repetitive inspection requirement.

Differences Between the Rule and Relevant Service Information
Operators should note that, unlike the procedures described in the alert service bulletins, this AD does not permit further flight if any cracking is detected in the spring tab. The FAA has determined that, because of the safety implications and consequences associated with such cracking, any subject spring tab that is found to be cracked must be replaced prior to further flight.

Whereas this AD provides for optional terminating action for Model 328-100 series airplanes, German airworthiness directive 2000-002 offers no such provision. However, the FAA has since been advised by the LBA and Dornier that terminating action is available for Model 328-100 series airplanes. Therefore, the FAA has determined that, for these airplanes, accomplishment of the pressure test inspection, and permanent repair of any cracked spring tab, as specified by Dornier Service Bulletin SB-328-55-307, dated December 1, 1999, is acceptable for terminating action for the repetitive inspections specified by Alert Service Bulletin ASB-328-55-028.

The alert service bulletins recommend that the tape checks be repeated at every line check and that the repetitive detailed visual inspection be repeated at every A-check; however, the repetitive intervals required by this AD are specified in terms of flight hours or days, which generally correspond to operators' line check and A-check schedules. The FAA has determined that the required repetitive intervals represent the maximum interval of time allowable for the affected airplanes to continue to operate, prior to accomplishing the required inspections, without compromising safety. Because maintenance schedules may vary from operator to operator, there would be no assurance that inspections accomplished according to a particular operator's line check or A-check schedule would be accomplished during the maximum allowable intervals.

Interim Action
This is considered to be interim action for Model 328-300 series airplanes. The manufacturer has advised that it currently is developing procedures that will positively address the unsafe condition addressed by this AD for these airplanes. Once these procedures are developed, approved, and available, 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 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.

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 aself-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 2000-NM-59-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 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.

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