AD 2000-07-04

This amendment adopts a new airworthiness directive (AD), applicable to certain Dornier Model 328-100 series airplanes, that requires repetitive tests of the flight idle backup system of the propeller control system; repetitive inspections to determine the level of wear of the pins and bushings of the cam followers on the power lever rods of the engine controls; and follow-on corrective actions, if necessary. This amendment also requires eventual replacement of the power lever and condition lever rods of the engine controls with new, improved parts, which constitutes terminating action for the repetitive tests and inspections. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent failure of the flight idle backup system. In the event of failure of the primary propeller control system, such failure of the flight idle backup system could lead to uncommanded movement of the pitch of the propeller blade to below flight idle and into reverse thrust during flight, and consequent reduced controllability of the airplane.

Final rule

2000-07-04 DORNIER LUFTFAHRT GMBH: Amendment 39-11658. Docket 99-NM-40-AD.

Applicability: Model 328-100 series airplanes having serial numbers (S/N) 3005 through 3098 inclusive, and S/N 3100, 3103, 3104, 3106, 3107, 3109, and 3110, on which Dornier Service Bulletin SB-328-76-268, dated August 11, 1998, or Revision 1, dated December 9, 1998, has not been accomplished; 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 (g) 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 flight idle backup system, which, in the event of failure of the primary propeller control system, could lead to uncommanded movement of the pitch of the propeller blade to below flight idle and into reverse thrust during flight, and consequent reduced controllability of the airplane, accomplish the following:

Flight Idle Backup Test
(a) Prior to the accumulation of 3,000 total flight hours, or within 3 days after the effective date of this AD, whichever occurs later, perform a test of the flight idle backup system of the propeller control system in accordance with Dornier Alert Service Bulletin ASB-328-76-024, Revision 1, dated August 5, 1998. If any discrepancy is detected, prior to further flight, accomplish the actions required by either paragraph (a)(1) or (a)(2) of this AD. Repeat the test thereafter at intervals not to exceed 1 day until accomplishment of the requirements of paragraph (c), (d), (e), or (f), as applicable.

(1) Repair in accordance with a method approved by either the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate; or the Luftfahrt-Bundesamt (LBA) (or its delegated agent). Or

(2) Accomplish the inspection required by paragraph (b) of this AD, and the applicable follow-on corrective actions required by paragraph (c), (d), or (e) of the AD; AND, if Type C wear is found during the inspection required by paragraph (b), prior to further flight, adjust or calibrate the power lever microswitches in accordance with Dornier Airplane Maintenance Manual JIC 76-11-05-820-000.

Inspection of Cam Followers of Power Lever Rods
(b) Prior to the accumulation of 3,000 total flight hours, or within 7 days after the effective date of this AD, whichever occurs later, perform a detailed visual inspection to determine the level of wear of the pins and bushings of the cam followers of the power lever rods of the engine controls, in accordance with Dornier Alert Service Bulletin ASB-328-76-024, Revision 1, dated August 5, 1998. Classify the level of wear for each power lever rod as specified in paragraphs (b)(1), (b)(2), and (b)(3) and accomplish the requirements of paragraph (c), (d), or (e) of this AD, as applicable, at the times specified in that paragraph.

(1) Type A wear: The bushing is worn such that the pin is visible in one or more locations.

(2) Type B wear: The bushing is worn, but the pin is not visible.

(3) Type C wear: The bushing is not worn.

Corrective Actions
(c) For power lever rods on which Type A wear is detected during the inspection required by paragraph (b) of this AD: Within 900 flight hours after accomplishment of that inspection, accomplish the requirements of paragraph (c)(1) or (c)(2) of this AD in accordance with Dornier Alert Service Bulletin ASB-328-76-024, Revision 1, dated August 5, 1998. Accomplishment of paragraph (c)(1) or (c)(2) terminates the tests required by paragraph (a) of this AD for that power lever rod only.

(1) Replace the power lever rod with a new power lever rod.

(2) Replace the pins and bushings with new pins and bushings, and accomplish paragraphs (c)(2)(i) and (c)(2)(ii) of this AD.

(i) Thereafter, accomplish follow-on inspections and corrective actions (i.e. inspections for wear or looseness of the replaced pins and bushings), at the times and in accordance with the Accomplishment Instructions of the alert service bulletin; and,

(ii) Within 900 flight hours after replacement of the pins and bushings, replace the power lever rod with a new power lever rod.

(d) For power lever rods on which Type B wear is detected during the inspection required by paragraph (b) of this AD: Thereafter, accomplish follow-on inspections and corrective actions at the times and in accordance with the Accomplishment Instructions of Dornier Alert Service Bulletin ASB-328-76-024, Revision 1, dated August 5, 1998, until the requirements of paragraph (f) of this AD are accomplished.

(e) For power lever rods on which Type C wear is detected during the inspection required by paragraph (b) of this AD: Determination of Type C wear terminates the tests required by paragraph (a) of this AD for that power lever rod only. Thereafter, accomplish follow-on inspections and corrective actions at the times and in accordance with the Accomplishment Instructions of Dornier Alert Service Bulletin ASB-328-76-024, Revision 1, dated August 5, 1998, until the requirements of paragraph (f) of this AD are accomplished.

Terminating Action
(f) Within 6 months after the effective date of this AD: Replace the power lever and condition lever rods of the engine controls with new, improved parts in accordance with Dornier Service Bulletin SB-328-76-268, Revision 1, dated December 9, 1998. Accomplishment of the replacement constitutes terminating action for the requirements of this AD.

NOTE 2: Replacement of the power lever and condition lever rods accomplished prior to the effective date of this AD in accordance with Dornier Service Bulletin SB-328-76-268, dated August 11, 1998, is considered acceptable for compliance with paragraph (f) of this AD.

Alternative Methods of Compliance
(g) 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. 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
(h) 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
(i) Except as required by paragraphs (a)(1) and (a)(2) of this AD, the actions shall be done in accordance with Dornier Alert Service Bulletin ASB-328-76-024, Revision 1, dated August 5, 1998; and Dornier Service Bulletin SB-328-76-268, Revision 1, dated December 9, 1998; as applicable. 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 4: The subject of this AD is addressed in German airworthiness directive 1998-344/3, dated February 11, 1999.

(j) This amendment becomes effective on May 16, 2000.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Dornier Model 328-100 series airplanes was published in the Federal Register on June 11, 1999 (64 FR 31520). That action proposed to require repetitive tests of the flight idle backup system of the propeller control system; repetitive inspections to determine the level of wear of the pins and bushings of the cam followers on the power lever rods of the engine controls; and follow-on corrective actions, if necessary. That action also proposed to require eventual replacement of the power lever and condition lever rods of the engine controls with new, improved parts, which constitutes terminating action for the repetitive tests and inspections.

Comment Received
Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the single comment received.

The commenter, the manufacturer, requests that paragraph (a) of the proposed AD be revised. The commenter states that, by requiring FAA or Luftfahrt-Bundesamt (LBA) approval if any discrepancy is discovered during the flight idle backup test required by paragraph (a), the AD would impose an undue hardship against operators of Dornier Model 328-100 series airplanes. The commenter suggests that paragraph (a) be revised to specify that if any discrepancy is detected, the inspection required by paragraph (b) should be performed prior to further flight. The commenter further suggests that, if Type C wear is found during that inspection, the power lever microswitches should be adjusted or calibrated; if Type A or B wear is found, the rod should be replaced per paragraph (f) of the AD, or the pin and bushing should be replaced as specified in paragraph C, section 6, of Dornier Alert Service Bulletin ASB 328-76-024, Revision 1, dated August 5, 1998 (which wascited as the appropriate source of service information for accomplishment of the inspections).

The FAA partially concurs. The FAA concurs that, if any discrepancy is found during the test required by paragraph (a) of the AD, accomplishment of the inspection required by paragraph (b) of the AD prior to further flight, with applicable corrective actions, constitutes an acceptable alternative to immediate repair in accordance with an FAA- or LBA-approved method. The FAA does not concur with the request to revise paragraph (a) to require such action solely, since both methods constitute acceptable corrective actions. To require only accomplishment of paragraph (b), and follow-on actions, as the commenter suggests, would also necessitate a reopening of the comment period, and thus further delay issuance of the final rule.

However, the FAA has determined that such an option may be incorporated into the AD as an alternative method of compliance to the repair required by paragraph (a). A new paragraph (a)(2) has been included in the final rule to specify such an option, with the provision that adjustment or calibration of the power lever microswitches must also be accomplished if Type C wear is found. Regarding findings of Type A or B wear, the FAA considers the existing follow-on corrective actions specified in paragraphs (c) and (d) of the AD to be adequate [those actions are required depending on the type of wear found during the inspection required by paragraph (b) of the AD]. Additionally, since replacement of all rods with improved rods is already an acceptable terminating action for the requirements of the AD, as specified in paragraph (f) of the AD, operators may choose to accomplish such corrective action at an earlier time if desired. No change is made to the final rule in regard to findings of Type A or B wear.

Conclusion
After careful review of the available data, including the comment noted above, the FAA has determined that air safetyand the public interest require the adoption of the rule with the change described previously. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD.

Cost Impact
The FAA estimates that 50 airplanes of U.S. registry will be affected by this AD. It will take approximately 1 work hour per airplane to accomplish the required test, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the test required by this AD on U.S. operators is estimated to be $3,000, or $60 per airplane, per test cycle.

It will take approximately 1 work hour per airplane to accomplish the required inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the inspection required by this AD on U.S. operators is estimated to be $3,000, or $60 per airplane, per inspection cycle.

It will take approximately 10 work hours per airplane to accomplish the required replacement, at an average labor rate of $60 per work hour. Required parts will be provided by the manufacturer at no cost to the operators. Based on these figures, the cost impact of the replacement required by this AD on U.S. operators is estimated to be $30,000, or $600 per airplane.

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted.

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.

For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it 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: