[Federal Register Volume 61, Number 135 (Friday, July 12, 1996)]
[Proposed Rules]
[Pages 36669-36671]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-17739]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 96-NM-08-AD]
RIN 2120-AA64


Airworthiness Directives; Shorts Model SD3-30, -60, and -SHERPA 
Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new Airworthiness 
Directive (AD) that is applicable to all Shorts Model SD3-30, -60, and 
-SHERPA series airplanes. This proposal would require a visual 
inspection to detect signs of exfoliation corrosion on the brackets of 
the flap hydraulic units, and rework or replacement of corroded 
brackets. This proposal is prompted by a report that exfoliation 
corrosion was found on the brackets of the flap hydraulic units. The 
actions specified by the proposed AD are intended to prevent such 
corrosion, and consequent reduced structural integrity of the brackets 
of the flap hydraulic units, which could result in the loss of the flap 
control and consequent reduced controllability of the airplane.

DATES: Comments must be received by August 29, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-08-AD, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056. Comments may be inspected at this location 
between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal 
holidays.
    The service information referenced in the proposed rule may be 
obtained from Short Brothers PLC, 2011 Crystal Drive, Suite 713, 
Arlington, Virginia 22202-3719.
    This information may be examined at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Phil Forde, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 
227-2146; fax (206) 227-1149.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 96-NM-08-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-103, Attention: Rules 
Docket No. 96-NM-08-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Civil Aviation Authority (CAA), which is the airworthiness 
authority for the United Kingdom, recently notified the FAA that an 
unsafe condition may exist on all Short Brothers Model SD3-30, -60, and 
-SHERPA series airplanes. The CAA advises that, during a maintenance 
check on a Model SD3-30 series airplane, exfoliation corrosion was 
found on the brackets of the flap hydraulic units. The effects of such 
corrosion could lead to the reduced structural integrity of the 
brackets of the flap hydraulic units. This condition, if not detected 
and corrected in a timely manner, could result in the loss of the flap 
control and consequent reduced controllability of the airplane.
    The brackets of the flap hydraulic units on certain Model SD3-60, 
and -SHERPA series airplanes are identical to those on the affected 
Model SD3-30 series airplanes. Therefore, all of these models may be 
subject to the same unsafe condition.

[[Page 36670]]

Explanation of Relevant Service Information

    Shorts has issued Service Bulletin SD330-27-34 (for Model SD3-30 
series airplanes), Service Bulletin SD360-27-24 (for Model SD3-60 
series airplanes), and Service Bulletin SD3 SHERPA-27-1 (for Model SD3-
SHERPA series airplanes), all dated September 12, 1995. These service 
bulletins describe procedures for a visual inspection to detect signs 
of exfoliation corrosion on the brackets of the flap hydraulic units, 
and rework or replacement of corroded brackets. The CAA classified 
these service bulletins as mandatory and issued airworthiness 
directives 005-09-95 (for Model SD3-30 series airplanes), 007-09-95 
(for Model SD3-60 series airplanes), and 008-09-95 (for Model SD3-
SHERPA series airplanes), in order to assure the continued 
airworthiness of these airplanes in the United Kingdom.

FAA's Conclusion

    This airplane model is manufactured in the United Kingdom and is 
type certificated for operation in the United States under the 
provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 
21.29) and the applicable bilateral airworthiness agreement. Pursuant 
to this bilateral airworthiness agreement, the CAA has kept the FAA 
informed of the situation described above. The FAA has examined the 
findings of the CAA, reviewed all available information, and determined 
that AD action is necessary for products of this type design that are 
certificated for operation in the United States.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of the same type design, the 
proposed AD would require a visual inspection to detect signs of 
exfoliation corrosion on the brackets of the flap hydraulic units, and 
rework or replacement of corroded brackets. The actions would be 
required to be accomplished in accordance with the service bulletins 
described previously.

Cost Impact

    The FAA estimates that 138 airplanes (50 Model SD3-30 series 
airplanes, 72 Model SD3-60 series airplanes, and 16 Model SD3-SHERPA 
series airplanes) of U.S. registry would be affected by this proposed 
AD, that it would take approximately 5 work hours per airplane to 
accomplish the proposed actions, and that the average labor rate is $60 
per work hour. Based on these figures, the cost impact of the proposed 
AD on U.S. operators is estimated to be $41,400, or $300 per airplane.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the proposed 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 proposed herein would 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 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this proposed 
regulation (1) Is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, 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 copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting 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.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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:

Short Brothers, PLC: Docket 96-NM-08-AD.

    Applicability: All Model SD3-30, -60, and -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 (b) 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 on the brackets of the flap hydraulic 
units, and consequent reduced structural integrity of those 
brackets, which could result in the loss of the flap control and 
consequent reduced controllability of the airplane; accomplish the 
following:
    (a) Within 90 days after the effective date of this AD, perform 
a visual inspection to detect signs of exfoliation corrosion on the 
brackets of the flap hydraulic units, in accordance with Shorts 
Service Bulletin SD330-27-34 (for Model SD3-30 series airplanes); 
Shorts Service Bulletin SD360-27-24 (for Model SD3-60 series 
airplanes); or Short Service Bulletin SD3 SHERPA-27-1 (for Model 
SD3-SHERPA series airplanes); all dated September 12, 1995; as 
applicable.
    (1) If no corrosion is detected, accomplish paragraph (a)(1)(i) 
or (a)(1)(ii) of this AD, as applicable.
    (i) For Model SD3-30 and -60 series airplanes: Repeat the visual 
inspection thereafter at intervals not to exceed 2,400 hours or 12 
months, whichever occurs first.
    (ii) For Model SD3-SHERPA series airplanes: Repeat the visual 
inspection thereafter at intervals not to exceed 12 months. -
    (2) If any corrosion is detected and it is within the limits 
specified in the applicable service bulletin, prior to further 
flight, rework the subject area in accordance with the applicable 
service bulletin. After accomplishment of the rework, accomplish 
paragraph (a)(2)(i) or (a)(2)(ii) of this AD, as applicable. -
    (i) For Model SD3-30 and -60 series airplanes: Repeat the visual 
inspection thereafter at intervals not to exceed 600 hours or 6 
months, whichever occurs first. -
    (ii) For Model SD3-SHERPA series airplanes: Repeat the visual 
inspection thereafter at intervals not to exceed 6 months.
    (3) If any corrosion is detected and it is outside the limits 
specified in the applicable service bulletin, prior to further 
flight, replace the bracket with a new bracket in accordance with 
the applicable service bulletin.
    (b) 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, Standardization Branch, ANM-113, 
FAA, Transport Airplane Directorate. Operators shall submit their 
requests through an appropriate FAA Principal Maintenance

[[Page 36671]]

Inspector, who may add comments and then send it to the Manager, 
Standardization Branch, ANM-113.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Standardization Branch, ANM-113.

    (c) 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.

    Issued in Renton, Washington, on July 8, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service. 
[FR Doc. 96-17739 Filed 7-11-96; 8:45 am]
BILLING CODE 4910-13-U