[Federal Register Volume 61, Number 149 (Thursday, August 1, 1996)]
[Proposed Rules]
[Pages 40159-40161]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-19524]


 ========================================================================
 Proposed Rules
                                                 Federal Register
 ________________________________________________________________________
 
 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
 ========================================================================
 

  Federal Register / Vol. 61, No. 149 / Thursday, August 1, 1996 / 
Proposed Rules  

[[Page 40159]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-07-AD]
RIN 2120-AA64


Airworthiness Directives; Short Brothers Model SD3-30 and SD3-
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 Short Brother Model SD3-30 and 
SD3-SHERPA series airplanes. This proposal would require inspections of 
the vertical fin-to-tailplane joint to detect any loose bolts; and, if 
necessary, inspections to detect elongation of bolt holes, and 
replacement with new bolts, if necessary. Additionally, the proposal 
would require inspections of the upper shear angle to detect pulled or 
loose rivets, and replacement of the shear angle using new rivets, if 
necessary. This proposal is prompted by reports of loose bolts in the 
vertical fin-to-tailplane joint and pulled or loose rivets in an upper 
shear angle. The actions specified by the proposed AD are intended to 
prevent reduced structural integrity of the vertical fin to tailplane 
joint due to such discrepancies of the bolts or rivets.

DATES: Comments must be received by September 11, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-07-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 date, 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-07-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-07-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 and SD3-
SHERPA series airplanes. The CAA advises that it has received reports 
of loose bolts that attach the vertical fin to the tailplane; this 
condition was found on a Model SD3-30 series airplane. Additionally, 
certain rivets in an upper shear angle were found to be pulled or 
loose. This condition, if not corrected, could result in reduced 
structural integrity of the vertical fin to tailplane joint.
    The bolts attaching the fin to the tailplane that are installed on 
Short Brothers Model SD3-30 series airplanes are similar in design to 
those installed on Short Brothers Model SD3-SHERPA series airplanes. 
Therefore, the FAA finds that both of these models are subject to the 
same unsafe condition identified in this proposal.

Explanation of Relevant Service Information

    Short Brothers has issued Shorts Service Bulletin SD330-55-18, 
dated April 20, 1995 (for Model SD3-30 series airplanes), and Shorts 
SD3 SHERPA Service Bulletin SD3 SHERPA-55-1, dated April 20, 1995 (for 
Model SD3-SHERPA series airplanes). These service bulletins describe 
procedures for repetitive visual inspections of the vertical fin-to-
tailplane joint to detect any loose bolts. For any airplane on which a 
loose bolt is found, the service bulletins describe procedures for 
visual inspections to detect elongation of the bolt holes, and repair, 
or replacement of the bolts with new bolts, if necessary. Additionally, 
the service bulletins describe procedures for repetitive visual 
inspections of the upper shear angle to detect pulled or loose rivets, 
and replacement of the shear angle using oversize rivets, if necessary. 
The CAA classified these service bulletins as mandatory in order to 
assure the continued airworthiness of these airplanes in the United 
Kingdom.

FAA's Conclusions

    These airplane models are manufactured in the United Kingdom and 
are type certificated for operation in the United States under the 
provisions of section 21.29 of the Federal Aviation

[[Page 40160]]

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 repetitive visual inspections of the vertical 
fin to tailplane joint to detect any loose bolts. For any airplane on 
which a loose bolt is found, the proposed AD would require visual 
inspections to detect elongation of the bolt holes, and repair or 
replacement of the bolt, if necessary. The proposed AD also would 
require visual inspections to detect elongation of any bolt holes, and 
repair, if necessary.
    Additionally, the proposal would require repetitive visual 
inspections of the upper shear angle to detect pulled or loose rivets, 
and replacement of the shear angle using oversize rivets, if necessary.
    These actions would be required to be accomplished in accordance 
with the service bulletins described previously.

Cost Impact

    The FAA estimates that 66 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 74 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 
$293,040, or $4,440 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 ADDRESSESS.

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-07-AD.

    Applicability: All Model SD3-30 and SD3-SHERPA series airplanes, 
certificated in any category.

    Note: 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 reduced structural integrity of the vertical fin to 
tailplane joint, accomplish the following:
    (a) Within 60 days after the effective date of this AD, perform 
a visual inspection to detect loose bolts in the vertical fin to 
tailplane joint, in accordance with Shorts Service Bulletin SD330-
55-18, dated April 20, 1995 (for Model SD3-30 airplanes), or Shorts 
SD3 SHERPA Service Bulletin SD3 SHERPA-55-1, dated April 20, 1995 
(for Model SD3-SHERPA airplanes), as applicable.
    (1) If no loose bolt is found, repeat the visual inspection 
thereafter at intervals not to exceed 1,500 flight hours.
    (2) If any loose bolt is detected, inspect the bolt for wear and 
distortion and inspect the hole for elongation, in accordance with 
the applicable service bulletin.
    (i) If the bolt and hole are within the limits specified by the 
applicable service bulletin, prior to further flight, refit the bolt 
with a new nut and washers, in accordance with the applicable 
service bulletin. Repeat the visual inspection thereafter at 
intervals not to exceed 1,500 flight hours.
    (ii) If the bolt is worn or distorted and the hole is within the 
limits specified by the applicable service bulletin, prior to 
further flight, replace the bolt, nut, and washers with a new bolt, 
a new nut, and a new washers, in accordance with the applicable 
service bulletin. Repeat the visual inspection thereafter at 
intervals not to exceed 1,500 flight hours.
    (iii) If the hole is elongated within the limits specified in 
the applicable service bulletin, prior to further flight, oversize 
the diameter of the hole, and replace the bolt, nut, and washers 
with a new matching bolt, new nut, and new washers, in accordance 
with the applicable service bulletin. Repeat the visual inspection 
thereafter at intervals not to exceed, 1,500 flight hours.
    (iv) If the hole is elongated beyond the limits specified in the 
applicable service bulletin, prior to further flight, repair in 
accordance with a method approved by the Manager, Standardization 
Branch, ANM-113, FAA, Transport Airplane Directorate.
    (b) Within 60 days after the effective date of this AD, perform 
a visual inspection to detect looseness or pulling of the rivets of 
attach shear angles SD3-32-0217/K and SD3-32-0218/K. If any 
looseness or pulling of the rivets is detected, prior to further 
flight, replace the shear angle using oversize rivets, in accordance 
with the applicable service bulletin.
    (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, Standardization Branch, ANM-113. 
Operators shall submit their requests through an appropriate FAA 
Principal Maintenance 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.

    (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

[[Page 40161]]

all location where the requirements of this AD can be accomplished.

    Issued in Renton, Washington, on July 25, 1996.
Darrel M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-19524 Filed 7-31-96; 8:45 am]
BILLING CODE 4910-13-M