AD 94-24-05

This amendment adopts a new airworthiness directive (AD), applicable to certain Short Brothers Model SD3-60 series airplanes, that requires installation of a certain time delay relay and associated wiring into a circuit of the rudder gust lock. This amendment is prompted by reports of inadvertent engagements of the rudder gust lock on in-service Model SD3-60 series airplanes. The actions specified by this AD are intended to prevent premature locking of the rudder gust lock, which could result in reduced controllability of the airplane in flight and during landing roll.

Final rule

94-24-05 SHORT BROTHERS, PLC: Amendment 39-9078. Docket 94-NM-96-AD.
Applicability: Model SD3-60 airplanes on which Modification 8112 (reference Shorts Service Bulletin SD360-27-16) has been installed, 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 use the authority provided in paragraph (b) to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition; or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any airplane from the applicability of this AD.

Compliance: Required as indicated, unless accomplished previously.

To prevent reduced controllability of the airplane in flight and during landing roll, accomplish the following:

(a) Within 90 days after the effective date of this AD, install a 10-second time delay relay, having part number TDD-AYOF-1002, and associated wiring into a circuit of the rudder gust lock, in accordance with Shorts Service Bulletin SD360-27-23, Revision 1, dated April 15, 1994.

(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 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.

(d) The installation shall be done in accordance with Shorts Service Bulletin SD360-27- 23, Revision 1, dated April 15, 1994. 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, PLC, 2011 Crystal Drive, Suite 713, Arlington, Virginia 22202-3719. 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.

(e) This amendment becomes effective on January 4, 1995.

FOR FURTHER INFORMATION CONTACT: Sam Grober, Aerospace Engineer, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 227-1187; fax (206) 227-1320.

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 certain Short Brothers Model SD3-60 series airplanes was published in the Federal Register on August 17, 1994 (59 FR 42186). That action proposed to require installation of a 10-second time delay relay, having part number TDD-AYOF-1002, and associated wiring into a circuit of the rudder gust lock.

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.

As a result of recent communications with the Air Transport Association (ATA) of America, the FAA has learned that, in general, some operators may misunderstand the legal effect of AD's on airplanes that are identified in the applicability provision of the AD, but that have been altered or repaired inthe area addressed by the AD. Under these circumstances, at least one operator appears to have incorrectly assumed that its airplane was not subject to an AD. On the contrary, all airplanes identified in the applicability provision of an AD are legally subject to the AD. If an airplane has been altered or repaired in the affected area in such a way as to affect compliance with the AD, the owner or operator is required to obtain FAA approval for an alternative method of compliance with the AD, in accordance with the paragraph of each AD that provides for such approvals. A note has been added to this final rule to clarify this requirement. The FAA has determined that this addition will neither increase the economic burden on any operator nor increase the scope of the AD.

The FAA estimates that 88 airplanes of U.S. registry will be affected by this AD, that it will take approximately 29 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Required parts will be supplied by the manufacturer at no cost to the operators. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $153,120, or $1,740 per airplane.

The total 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.

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 readas follows:
Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89.

39.13 - [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: