[Federal Register Volume 64, Number 204 (Friday, October 22, 1999)]
[Rules and Regulations]
[Pages 56960-56962]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-27326]


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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.

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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

[[Page 56961]]

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

    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:

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.

[[Page 56962]]

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. 99-27326 Filed 10-21-99; 8:45 am]
BILLING CODE 4910-13-U