[Federal Register Volume 64, Number 197 (Wednesday, October 13, 1999)]
[Rules and Regulations]
[Pages 55409-55411]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-26277]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-137-AD; Amendment 39-11367; AD 99-21-22]
RIN 2120-AA64


Airworthiness Directives; Short Brothers Model SD3-30, SD3-60, 
SD3 SHERPA, and SD3-60 SHERPA 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 SD3-30, SD3-60, SD3 SHERPA, and 
SD3-60 SHERPA series airplanes, that requires a visual inspection to 
detect corrosion of the shear decks and ribs of the left and right stub 
wings; follow-on corrective actions, if necessary; and drilling of new 
drain holes in the lower shear decks. 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 corrosion of the stub wing shear decks and ribs, 
which could result in cracking or failure of the stub wing structure.

DATES: Effective November 17, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of November 17, 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 SD3-30, 
SD3-60, SD3 SHERPA, and SD3-60 SHERPA series airplanes was published in 
the Federal Register on June 23, 1999 (64 FR 33439). That action 
proposed to require a one-time borescope inspection to detect corrosion 
of the shear decks and ribs of the left and right stub wings, follow-on 
corrective actions, if necessary; and drilling of new drain holes in 
the lower shear decks.

Comments Received

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

Request To Revise Inspection Method

    One commenter suggests that the proposed AD be revised to include 
instructions to remove the main landing gear (MLG) forward pintle pin 
(which requires removal of the wheel lever assemblies) and to steam 
clean the areas identified by the referenced service bulletin. The 
commenter also suggests that all reference to use of a borescope be 
deleted to prevent misinterpretation. The commenter states that the 
proposed AD dictates a different inspection method than the referenced 
manufacturer's service bulletin, since it does not reference removing 
the MLG or steam cleaning the area, and requires a borescope 
inspection. Such a method may actually degrade safety, since without 
removal of the MLG forward pintle pins, thorough cleaning and 
subsequent inspection of the area cannot be accomplished. The commenter 
states that most technicians

[[Page 55410]]

would interpret the requirement to use a borescope to mean that removal 
of the MLG is not required, since the purpose of a borescope is to 
enable inspection without disassembly.
    The FAA has determined that clarification of the AD is necessary. 
The intent of the AD is to require the same inspection methods 
specified in the referenced service bulletins. The actions required by 
paragraph (a) of the AD are specifically required to be accomplished in 
accordance with Part A of the Accomplishment Instructions of the 
applicable service bulletin. Part A includes instructions for removal 
of the port and starboard MLG, and steam cleaning of the affected area, 
prior to inspection. Part A, paragraph 7., also specifies to ``visually 
inspect inner surfaces and interfaces between ribs for corrosion using 
a borescope.'' The FAA does not specify in an AD each action described 
in the referenced service information, since such restatement would be 
unnecessarily duplicative and could result in misunderstanding of the 
requirements. However, to avoid any confusion as to the actions 
required by this AD, the FAA has revised paragraph (a) of the AD to 
require that all actions in Part A of the service bulletin be 
accomplished. The FAA has also restated the borescope inspection 
requirement to specify a ``visual inspection using a borescope.''

Request To Allow Use of Alternate Service Information

    One commenter requests that the proposed AD be revised to allow 
accomplishment of the required inspections on Short Brothers Model SD3-
60 SHERPA airplanes having serial numbers SH3420 through SH3428 in 
accordance with Shorts Service Bulletin SD360-53-43, Revision 1, dated 
November 27, 1998. This service bulletin was specified in the proposed 
AD as the appropriate source of service information for Model SD3-60 
airplanes, and SD360-Sherpa-53-4, dated November 27, 1998, was 
specified as appropriate for Model SD3-60 SHERPA airplanes. The 
commenter provides documentation showing that the airplane manufacturer 
has previously accomplished service bulletin SD360-53-43 on certain 
Model SD3-60 SHERPA airplanes, and requests that the FAA consider such 
action to be adequate for compliance with the inspection required by 
this AD.
    The FAA concurs. The actions described in Shorts Service Bulletins 
SD360-53-43, Revision 1, and SD360-Sherpa-53-4 are substantially 
equivalent. The FAA has determined that for Model SD3-60 SHERPA series 
airplanes, inspections accomplished in accordance with SD360-53-43, 
dated November 4, 1997, or Revision 1, dated November 27, 1998, are 
acceptable for compliance with the initial inspection required by 
paragraph (a) of this AD. A ``NOTE'' has been added to the final rule 
to provide such credit.

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 with the changes described 
previously. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Cost Impact

    The FAA estimates that 112 airplanes of U.S. registry will be 
affected by this AD, that it will take approximately 100 work hours per 
airplane to accomplish the required 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 $672,000, or 
$6,000 per airplane.
    The cost impact figure discussed above is 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:

99-21-22   Short Brothers PLC: Amendment 39-11367. Docket 98-NM-137-
AD.

    Applicability: All Model SD3-30, SD3-60, SD3 SHERPA, and SD3-60 
SHERPA 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 (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 corrosion of the stub wing shear decks and ribs, 
which could result in cracking or failure of the stub wing 
structure, accomplish the following:

Inspection and Corrective Actions

    (a) Within 6 months after the effective date of this AD, 
accomplish all actions, including a visual inspection using a 
borescope, specified in Part A of the Accomplishment Instructions of 
the applicable Shorts Service Bulletin specified below, all dated 
November 27, 1998 (hereinafter referred to as the applicable service 
bulletin), in the areas of the stub wing shear decks and ribs to 
detect corrosion, and drill new drain holes in the lower shear 
decks, in accordance with the applicable service bulletin:
     SD330-53-68 (for Model SD3-30 series airplanes);
     SD360-53-43, Revision 1 (for Model SD3-60 series 
airplanes);
     SD3 Sherpa-53-4 (for Model SD3 SHERPA series 
airplanes); and

[[Page 55411]]

     SD360-Sherpa-53-4 (for Model SD3-60 SHERPA series 
airplanes).

    Note 2: In the case where no corrosion is detected during the 
inspection described in Part A of the Accomplishment Instructions of 
the applicable service bulletin, the service bulletin specifies 
accomplishment of follow-on repetitive inspections of this area as 
specified in Short Brothers Aircraft Maintenance Programme, Chapter 
5-26-57.

    Note 3: For Model SD3-60 SHERPA series airplanes, accomplishment 
of the actions required by paragraph (a) of this AD in accordance 
with Shorts Service Bulletin SD360-53-43, dated November 4, 1997, or 
Revision 1, dated November 27, 1998, is acceptable for compliance 
with the requirements of that paragraph.

    (b) Except as provided by paragraph (c) of this AD: If any 
corrosion is detected during the inspection required by paragraph 
(a) of this AD, prior to further flight, accomplish corrective 
actions (i.e., additional inspections, removal of corrosion, 
replacement of components), as applicable, in accordance with Part B 
of the Accomplishment Instructions of the applicable service 
bulletin. Thereafter, repeat the inspection required by paragraph 
(a) of this AD at intervals not to exceed 12 months.
    (c) If any corrosion condition is found for which the applicable 
service bulletin specifies that Short Brothers is to be contacted 
for an appropriate repair action: Prior to further flight, repair in 
accordance with a method approved by either the Manager, 
International Branch, ANM-116, FAA, Transport Airplane Directorate, 
or the Civil Aviation Authority (CAA) of the United Kingdom (or its 
delegated agent).

Reporting Requirement

    (d) Within 10 days after accomplishment of the initial 
inspection required by paragraph (a) of this AD, or within 30 days 
after the effective date of this AD, whichever occurs later, submit 
a report of the inspection findings (positive or negative) to: Team 
Leader, Service Engineering-Aerospace Customer Support Short 
Brothers plc, Belfast, N. Ireland. Information collection 
requirements contained in this regulation have been approved by the 
Office of Management and Budget (OMB) under the provisions of the 
Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have 
been assigned OMB Control Number 2120-0056.

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. 
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 Shorts Service 
Bulletin SD330-53-68, dated November 27, 1998, Shorts Service 
Bulletin SD360-53-43, Revision 1, dated November 27, 1998, Shorts 
Service Bulletin SD3 Sherpa-53-4, dated November 27, 1998, or Shorts 
Service Bulletin SD360-Sherpa-53-4, dated November 27, 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 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 5: The subject of this AD is addressed in British 
airworthiness directives 006-11-97, 006-11-98, 007-11-98, and 008-
11-98.

    (h) This amendment becomes effective on November 17, 1999.

    Issued in Renton, Washington, on October 4, 1999.
D. L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-26277 Filed 10-12-99; 8:45 am]
BILLING CODE 4910-13-P