AD 98-07-21

This amendment adopts a new airworthiness directive (AD), applicable to certain Lockheed Model 1329-23 and -25 series airplanes, that requires replacement of a certain tailpipe V-band coupling with a new tailpipe V-band coupling. This amendment is prompted by reports indicating that the flight crew received a fire/overheat warning as a result of displacement of engine tailpipes, which allowed hot exhaust gases into the engine bypass duct. The actions specified by this AD are intended to prevent such displacement, which could result in escape of the hot exhaust gases from the engine tailpipe, and consequent damage to adjacent structure

Final rule

98-07-21 LOCKHEED AERONAUTICAL SYSTEMS COMPANY: Amendment 39-10442. Docket 97-NM-93-AD.
Applicability: Model 1329-25 series airplanes equipped with an engine tailpipe V-band coupling, part number (P/N) NH1002299-10; and Model 1329-23 series airplanes that have been modified in accordance with Supplemental Type Certificate (STC) SA2326SW, equipped with an engine tailpipe V-band coupling, P/N NH1002299-10; 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 (c) 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 displacement of the engine tailpipes, which could result in escape of hot exhaust gases from the engine tailpipe, and consequent damage to adjacent structure, accomplish the following:

(a) Within 12 months after the effective date of this AD, replace the tailpipe V-band coupling having P/N NH1002299-10 with a new, redesigned coupling having P/N NH1003605-10, in accordance with Step 1, Figure 71-1, of Lockheed JetStar II Handbook of Operating and Maintenance Instructions, undated (for Model 1329-25 series airplanes); or Step 8, Figure 71-1(S), of Garrett Airesearch Aviation Company 731 JetStar document, undated (for Model 1329-23 series airplanes); as applicable.

NOTE 2: Installation of P/N NH1003605-10 prior to the effective date of this AD is considered acceptable for meeting the replacement requirement of paragraph (a) of this AD. Compliance may be demonstrated by confirmation that the airplane maintenance records reflect installation of P/N NH1003605-10 V-band couplings.

(b) As of 12 months after the effective date of this AD, no person shall install a tailpipe V-band coupling, P/N NH1002299-10, on any airplane.

(c) 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, Atlanta Aircraft Certification Office (ACO), FAA, Small 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, Atlanta ACO.

NOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Atlanta ACO.(d) 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.

(e) This amendment becomes effective on May 18, 1998.

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 Lockheed Model 1329-23 and -25 series airplanes was published in the Federal Register on January 8, 1998 (63 FR 1076). That action proposed to require replacement of a certain tailpipe V-band coupling with a new tailpipe V-band coupling.

The FAA has been informed that a substantial number of airplanes already have been equipped with the subject engine tailpipe V-band couplings, part number (P/N) NH1003605-10. The FAA finds that, if new couplings already have been installed and such installation is reflected in airplane service records, independent confirmation is unnecessary. Therefore, the body of the AD has been revised to incorporate a note that allows this compliance option.

Comments
Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were submitted in response to the proposal or the FAA's determination of the cost to the public.

Conclusion
The FAA has determined that air safety and the public interest require the adoption of the rule, with the changes previously described.

Cost Impact
There are approximately 91 Model 1329-25 and -23 series airplanes of the affected design in the worldwide fleet.

The FAA estimates that 25 Model 1329-25 (JetStar II) series airplanes of U.S. registry will be affected by this AD, that it will take approximately 60 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Required parts will cost approximately $726 per airplane. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $108,150, or $4,326 per airplane.

The FAA estimates that 35 Model 1329-23 (731 JetStar) series airplanes of U.S. registry will be affected by this AD, that it will take approximately 60 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Required parts will cost approximately $1,200 per airplane. Based on these figures, the cost impact of the AD on U.S. operators of these airplanes is estimated to be $168,000, or $4,800 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 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 of a Federalism Assessment.

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, 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 DIRECTIVES1. 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: