Airworthiness directives: Short Brothers,
[Federal Register: October 22, 1999 (Volume 64, Number 204)]
[Rules and Regulations]
[Page 56960-56962]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr22oc99-7]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 99-NM-52-AD; Amendment 39-11383; AD 99-22-05]
RIN 2120-AA64
Airworthiness Directives; Short Brothers Model SD3-60 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
SUMMARY: This amendment adopts a new airworthiness directive (AD), applicable to all Short Brothers Model SD3-60 series airplanes, that requires repetitive inspections of the elevator trim control cables for signs of wear damage or broken wires; replacement of damaged or broken cables with certain new cables; and replacement of all 7 x 7 cables with 7 x 19 cables. 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 elevator trim cable due to fatigue cracking, which if not corrected, could result in reduced controllability of the airplane.
DATES: Effective November 26, 1999.
The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of November 26, 1999.
ADDRESSES: The service information referenced in this AD may be obtained from Short Brothers, Airworthiness & Engineering Quality, P.O. Box 241, Airport Road, Belfast BT3 9DZ, Northern Ireland. This information may be examined at the Federal Aviation Administration (FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: Norman B. Martenson, Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2110; fax (425) 227-1149.
SUPPLEMENTARY INFORMATION: 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 all Short Brothers Model SD3-60 series airplanes was published in the Federal Register on August 4, 1999 (64 FR 42291). That action proposed to require repetitive inspections of the elevator trim control cables for signs of wear damage or broken wires; replacement of damaged or broken cables with certain new cables; and replacement of all 7 x 7 cables with 7 x 19 cables.
Comment Received
Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comment received.
Request To Review Inspection Interval
One commenter requests that the proposed AD be revised to either delete the requirement to repetitively inspect to detect wear damage or broken wires of the elevator trim cables at intervals of 12 months, or extend the intervals to 24 months. (The proposed AD currently requires repetitive inspections at intervals not to exceed ``12 months or 2,400 flight hours, whichever occurs first''). The commenter states that the cause of the cable degradation is the repeated operation/movement of the cables over small radius pulleys, which is a factor of flights and flight hours, not calendar time. The commenter also notes that the 2,400 flight hour interval does not correlate with 12 months for these airplanes, since most are operated at significantly less than 2,400 flight hours per year. The commenter also states that the current SD3- 60 maintenance program does not specify inspection of the elevator trim cables at 12 months, and does not contain any inspection with a 12- month interval where numerous units are to be removed, as would be required in order to inspect the elevator trim cable circuit. The commenter states that Shorts Service Bulletin SD360-27-27, Revision 1, dated April 1, 1999, is in error in referencing Revision 8 of the maintenance program as containing such inspection intervals.
The FAA does not concur with the request to delete or revise the requirement for inspections at 12-month intervals. Service history has shown these cables to be susceptible to
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breakage earlier than anticipated. After several incidents in which segments of the elevator trim cable severed in flight, more frequent inspections of the cables have been deemed necessary in order to preclude such in-flight events.
Additionally, the inspection intervals in the proposed AD were intended to parallel normally scheduled maintenance for the majority of affected operators. Shorts Information Letter SD360-IL-199, Revision 1, dated April 1999, states that a review of the current maintenance program inspection intervals has resulted in the proposal to reduce this inspection interval from a ``D-Check'', which is equivalent to 4,800 flight hours or 2 years, to a ``C-Check'' interval, which is equivalent to the 2,400 flight hour or 12-month interval required by this AD. However, under the provisions of paragraph (c) of the AD, the FAA may approve an operator's request for adjustment of the compliance time intervals if data are provided to substantiate that such an adjustment would constitute an acceptable level of safety. The FAA has determined that the requirement for inspections at the intervals specified in this AD is appropriate to address the identified unsafe condition. No change is made to the final rule.
Conclusion
After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed.
Cost Impact
The FAA estimates that 45 airplanes of U.S. registry will be affected by this AD, that it will take approximately 20 work hours per airplane to accomplish the required cable inspection, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $54,000, or $1,200 per airplane, per inspection cycle.
The FAA estimates that it will take approximately 75 work hours per airplane to accomplish the required cable replacement, and that the average labor is $60 per work hour. Required parts will cost approximately $4,500 per airplane. Based on these figures, the cost impact of the cable replacement required by this AD on U.S. operators is estimated to be $405,000, or $9,000 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, 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
-
The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
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Section 39.13 is amended by adding the following new airworthiness directive:
99-22-05 Short Brothers, PLC: Amendment 39-11383. Docket 99-NM-52- AD.
Applicability: All Model SD3-60 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 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 failure of the elevator trim cable due to fatigue, which if not corrected, could result in reduced controllability of the airplane, accomplish the following:
Inspection
(a) Within 12 months after the effective date of this AD, perform a visual inspection to detect wear damage or broken wires of the elevator trim cables, in accordance with Shorts Service Bulletin SD360-27-27, Revision 1, dated April 1, 1999.
(1) If no wear damage or broken wire is detected, repeat the inspection specified in paragraph (a) of this AD thereafter at intervals not to exceed 12 months or 2,400 flight hours, whichever occurs first.
(2) If any wear damage or broken wire is detected, prior to further flight, replace the damaged cable with a 7 x 19 cable in accordance with the service bulletin. Repeat the inspection specified in paragraph (a) of this AD thereafter at intervals not to exceed 12 months or 2,400 flight hours, whichever occurs first.
Replacement and Inspection
(b) Prior to the accumulation of 10,000 total flight hours, or within 12 months after the effective date of this AD, whichever occurs later, replace all 7 x 7 elevator trim cables with 7 x 19 cables in accordance with Shorts Service Bulletin SD360-27-27, Revision 1, dated April 1, 1999. Repeat the inspection specified in paragraph (a) of this AD thereafter at intervals not to exceed 12 months or 2,400 flight hours, whichever occurs first.
Alternative Methods of Compliance
(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, 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.
Special Flight Permits
(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.
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Incorporation by Reference
(e) The actions shall be done in accordance with Shorts Service Bulletin SD360-27-27, Revision 1, dated April 1, 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 Short Brothers, Airworthiness & Engineering Quality, P.O. Box 241, Airport Road, Belfast BT3 9DZ, Northern Ireland. 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 3: The subject of this AD is addressed in British airworthiness directive 016-11-98.
(f) This amendment becomes effective on November 26, 1999.
Issued in Renton, Washington, on October 14, 1999. D.L. Riggin, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 99-27326Filed10-21-99; 8:45 am]
BILLING CODE 4910-13-U
