Airworthiness Directives; Short Brothers Model SD3-60 SHERPA Series Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-138-AD; Amendment 39-10799; AD 98-20-32]

RIN 2120-AA64

Airworthiness Directives; Short Brothers Model SD3-60 SHERPA

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 SHERPA series airplanes,

that requires an initial cleaning and visual inspection of the distance

piece and adjacent side plates of the fuselage wing strut pick-up of

the left- and right-stub wings to detect corrosion; rework or

replacement of damaged components; and, for certain conditions, follow-

on repetitive cleaning and visual inspections of reworked components.

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 detect and correct

corrosion of the distance piece and adjacent side plates, which could

result in reduced strength of the wing strut attachment to the stub

wing on the fuselage, and consequent reduced structural integrity of

the main wing.

DATES: Effective October 30, 1998.

The incorporation by reference of certain publications listed in

the regulations is approved by the Director of the Federal Register as

of October 30, 1998.

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

SHERPA series airplanes was published in the Federal Register on August

7, 1998 (63 FR 42288). That action proposed to require an initial

cleaning and visual inspection of the distance piece and adjacent side

plates of the fuselage wing strut pick-up of the left-and right-stub

wings to detect corrosion; rework or replacement of damaged components;

and, for certain conditions, follow-on repetitive cleaning and visual

inspections of reworked components.

Comments

Interested persons have been afforded an opportunity to participate

in the making of this amendment. No comments were submitted in response

to the proposal or the FAA's determination of the cost to the public.

Conclusion

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 28 airplanes of U.S. registry will be

affected by this AD, that it will take approximately 5 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 inspection required by this AD on U.S. operators is

estimated to be $8,400, or $300 per airplane, per inspection cycle.

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

[[Page 51282]]

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:

98-20-32 Short Brothers PLC: Amendment 39-10799. Docket 98-NM-138-

AD.

Applicability: All Model 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 detect and correct corrosion of the distance piece and

adjacent side plates of the fuselage wing strut pick-up of the left-

and right-stub wings, which could result in reduced strength of the

wing strut attachment to the stub wing on the fuselage, and

consequent reduced structural integrity of the main wing, accomplish

the following:

(a) Within 90 days after the effective date of this AD, clean

the pockets in the horizontal and vertical legs of the distance

piece and adjacent faces of the side plates at the wing strut pick-

up area on the stub wing, and perform a visual inspection to detect

corrosion; in accordance with Shorts Service Bulletin SD3-60 SHERPA-

53-2, dated November 4, 1997.

(b) If no corrosion is detected during the inspection required

by paragraph (a) of this AD, prior to further flight, apply

additional corrosion protection treatment in accordance with Shorts

Service Bulletin SD3-60 SHERPA-53-2, dated November 4, 1997.

(c) If any corrosion is detected, prior to further flight, after

cleaning and removing the corrosion from the distance piece and side

plates in accordance with Shorts Service Bulletin SD3-60 SHERPA-53-

2, dated November 4, 1997, accomplish paragraph (c)(1) or (c)(2) of

this AD, as applicable.

(1) If the depth of corrosion is within the limits specified in

the service bulletin, apply additional corrosion protection

treatment in accordance with the service bulletin.

(2) If the depth of corrosion is outside the limits specified in

the service bulletin, accomplish either paragraph (c)(2)(i) or

(c)(2)(ii) of this AD. Thereafter, repeat the detailed visual

inspection required by paragraph (a) of this AD at intervals not to

exceed 600 hours time-in-service or 90 days, whichever occurs first.

(i) Rework the damaged components in accordance with a method

approved by either the Manager, International Branch, ANM-116, FAA,

Transport Airplane Directorate; or the Civil Aviation Authority of

the United Kingdom (or its delegated agent). Thereafter, repeat the

detailed visual inspection required by paragraph (a) of this AD at

intervals not to exceed 600 hours time-in-service or 90 days,

whichever occurs first.

(ii) Replace the damaged components with new components in

accordance with Shorts SD3-60 Sherpa Maintenance Programme Manual,

Section 5-26-57, page 9, dated July 17, 1995.

(d) Within 10 days after accomplishing the initial cleaning and

inspection required by paragraph (a) of this AD, submit a report of

the inspection results (both positive and negative findings) to

Short Brothers, PLC. 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.

(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 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.

(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.

(g) Except as provided by paragraphs (c)(2)(i), (c)(2)(ii), and

(d) of this AD, the actions shall be done in accordance with Shorts

Service Bulletin SD3-60 SHERPA-53-2, dated November 4, 1997. 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 004-11-97.

(h) This amendment becomes effective on October 30, 1998.

Issued in Renton, Washington, on September 17, 1998.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 98-25475 Filed 9-24-98; 8:45 am]

BILLING CODE 4910-13-P