AD 96-22-04

This amendment adopts a new airworthiness directive (AD), applicable to certain British Aerospace Model Avro 146-RJ70A, -RJ85A, and -RJ100A airplanes, that requires repetitive inspections for cracking of fuselage frame 29, and repair, if necessary. This amendment is prompted by results of fatigue testing, which revealed fatigue cracking in the web and inboard flange of frame 29. The actions specified by this AD are intended to prevent reduced structural integrity of the fuselage due to fatigue cracking in frame 29.

Final rule

96-22-04 BRITISH AEROSPACE: Amendment 39-9793. Docket 95-NM-213-AD.
Applicability: Model Avro 146-RJ70A, -RJ85A, and -RJ100A airplanes; as listed in Avro International Aerospace Inspection Service Bulletin S.B. 53-131, dated March 29, 1995; certificated in any category.

NOTE 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been otherwise 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 (d) 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 fuselage of the airplane due to fatigue cracking in frame 29, accomplish the following:

(a) Perform a detailed visual inspection for cracking of frame 29 between stringers 12 and 18 on the left and right side of the fuselage, in accordance with Avro International Aerospace Inspection Service Bulletin S.B. 53-131, dated March 29, 1995. If the polymer coating on frame 29 prevents a detailed visual inspection, perform a surface eddy current inspection for cracking in accordance with the service bulletin. Perform the inspections at the time specified in paragraph (a)(1), (a)(2), or (a)(3) of this AD, as applicable.

(1) For Model Avro 146-RJ100A airplanes on which British Aerospace Modification HCM01411A, HCM01411B, or HCM01411C has not been accomplished: Perform the inspection within 6 months after the effective date of thisAD, or prior to the accumulation of 12,000 total landings, whichever occurs later. Repeat the inspection thereafter at intervals not to exceed 4,000 landings.

(2) For Model Avro 146-RJ70A and -RJ85A airplanes on which British Aerospace Modification HCM01411A or HCM01411C has not been accomplished: Perform the inspection within 6 months after the effective date of this AD, or prior to the accumulation of 24,000 total landings, whichever occurs later. Repeat the inspection thereafter at intervals not to exceed 4,000 landings.

(3) For Model Avro 146-RJ100A airplanes on which British Aerospace Modification HCM01411C has been accomplished, but on which British Aerospace Modification HCM01411A or HCM01411B has not been accomplished: Perform the inspection within 6 months after the effective date of this AD, or prior to the accumulation of 68,000 total landings, whichever occurs later. Repeat the inspection thereafter at intervals not to exceed 4,000 landings.

(b) Ifany cracking is found during any inspection required by paragraph (a) of this AD: Prior to further flight, repair in accordance with a method approved by the Manager, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate.

(c) Accomplishment of the modification of each affected bolt position in accordance with Avro International Aerospace Inspection Service Bulletin S.B. 53-131, dated March 29, 1995, prior to the embodiment times shown in Table A of that service bulletin, constitutes terminating action for the repetitive inspections required by paragraph (a) of this AD.

NOTE 2: Avro Repair Instruction Leaflet (RIL) HC536H9168 provides detailed instructions for modification of all bolt positions in the affected areas of frame 29.

(d) 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 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Standardization Branch, ANM-113.

(e) 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.

(f) The inspection and modification shall be done in accordance with Avro International Aerospace Inspection Service Bulletin S.B. 53-131, dated March 29, 1995. 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 Limited, Avro International Aerospace Division, Customer Support, Woodford Aerodrome, Woodford, Cheshire SK7 1QR, England. 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.

(g) This amendment becomes effective on December 11, 1996.

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 Model Avro 146-RJ70A, -RJ85A, and -RJ100A airplanes was published in the Federal Register on August 7, 1996 (61 FR 41037). That action proposed to require repetitive visual inspections to detect cracking of the fuselage at frame 29.

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 11 British Aerospace Model Avro 146-4J70A, - RJ85A, and -RJ100A airplanes of U.S. registry will be affected by this AD, that it will take approximately 9 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $5,940, or $540 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 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 asfollows:
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: