AD 99-25-06

This amendment adopts a new airworthiness directive (AD), applicable to certain British Aerospace (Jetstream) Model 4101 airplanes, that requires a one-time inspection of the bottom aft roller of the main baggage-bay door structure for cracking or damage to the sub-frame; repetitive operational tests to determine if the counter-balance motor functions properly; and corrective actions, if necessary. 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 sub-frame damage, which, if left undetected, could cause rapid decompression of the airplane and consequent injury to passengers and crew.

Final rule

99-25-06 BRITISH AEROSPACE REGIONAL AIRCRAFT [Formerly Jetstream Aircraft Limited; British Aerospace (Commercial Aircraft) Limited]: Amendment 39-11449. Docket 98-NM-296-AD. Issued November 24, 1999.
Applicability: British Aerospace (Jetstream) Model 4101 airplanes, as listed in Jetstream Service Bulletin J41-52-060, dated August 31, 1998; 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 (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 sub-frame damage, which, if left undetected, could cause rapid decompression of the airplane and consequent injury to passengers and crew, accomplish the following:

Visual Inspection
(a) Within 1,500 landings or within 5 months after the effective date of this AD, whichever occurs first, perform a one-time general visual inspection of the bottom aft roller of the main baggage bay door structure to check for cracking or damage to the sub-frame in accordance with Jetstream Service Bulletin J41-52-060, dated August 31, 1998. If any cracking or damage is found, 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 (or itsdelegated agent). For a repair method to be approved by the Manager, International Branch, ANM-116, as required by this paragraph, the Manager s approval letter must specifically reference this AD.

NOTE 2: For the purposes of this AD, a general visual inspection is defined as "A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or drop-light, and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being check."

Operational Test
(b) Within 30 days after the effective date of this AD, perform an operational test to determine if the counter-balance motor of the main baggage bay door functions properly in accordance with Jetstream Service Bulletin J41-52-060, dated August 31, 1998. Repeat the operational test thereafter at intervals not to exceed 5 days. If the motor fails during any operational test, within 10 flights after accomplishing the test, either replace the motor with a new motor or repair in accordance with the service bulletin, and accomplish the actions specified in paragraph (a) of this AD.

Alternative Methods of Compliance
(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, 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 3: 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
(d) Special flight permits may beissued 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
(e) Except as provided by paragraph (a) of this AD, the actions shall be done in accordance with Jetstream Service Bulletin J41-52-060, dated August 31, 1998. 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 British Aerospace Regional Aircraft American Support, 13850 Mclearen Road, Herndon, Virginia 20171. 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 4: The subject of this AD is addressed in British airworthiness directive 005-08-98.

(f)This amendment becomes effective on January 12, 2000.

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 British Aerospace (Jetstream) Model 4101 airplanes was published in the Federal Register on October 8, 1999 (64 FR 54795). That action proposed to require a one-time inspection of the bottom aft roller of the main baggage-bay door structure for cracking or damage to the sub-frame; repetitive operational tests to determine if the counter-balance motor functions properly; and corrective actions, if necessary.

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 43 airplanes of U.S. registry will be affected by this AD.

It will take approximately 3 work hours per airplane to accomplish the required inspection, at an average labor rate of $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 $7,740, or $180 per airplane.

It will take approximately 1 work hour per airplane to accomplish the required test, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the test required by this AD on U.S. operators is estimated to be $2,580, or $60 per airplane, per test cycle.

The cost impact figures discussed above are 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.

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