AD 97-04-17

This amendment adopts a new airworthiness directive (AD), applicable to certain British Aerospace Model BAe 146 series airplanes and Model Avro 146-RJ series airplanes, that requires inspections to detect leakage of hydraulic fluid from the lock jack assemblies of the main landing gear (MLG), and eventual replacement of those assemblies with new or serviceable assemblies. This amendment is prompted by reports of leakage of hydraulic fluid from lock jack assemblies due to a manufacturing forging defect that extends through the wall of the lock jack assembly. The actions specified by this AD are intended to prevent leakage of hydraulic fluid from the lock jack assemblies of the MLG, which, in conjunction with a hot brake, could cause a fire in the MLG bay.

Final rule

97-04-17 BRITISH AEROSPACE REGIONAL AIRCRAFT LIMITED, AVRO INTERNATIONAL AEROSPACE DIVISION (formerly British Aerospace, plc; British Aerospace Commercial Aircraft Limited): Amendment 39-9942. Docket 96-NM-48-AD.
Applicability: Model BAe 146 series airplanes and Model Avro 146-RJ series airplanes having lock jack assemblies of the main landing gear as listed in British Aerospace Inspection Service Bulletin SB 32-103, Revision 1, dated February 22, 1991; 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 leakage of hydraulic fluid from the lock jack assemblies of the main landing gear (MLG), which, in conjunction with a hot brake, could cause a fire in the MLG bay; accomplish the following:

(a) Within 30 days after the effective date of this AD, verify the serial number of all lock jack assemblies, part number 104275001, of the MLG.

NOTE 2: Verification may be accomplished by a review of appropriate records.

(1) If no lock jack assembly has a serial number as listed in British Aerospace Inspection Service Bulletin SB 32-103, Revision 1, dated February 22, 1991, no further action is required by this paragraph.

(2) If any lock jack assembly has a serial number as listed in British Aerospace Inspection Service Bulletin SB 32-103, Revision 1, dated February 22, 1991, prior to further flight, perform a visual inspection to detect any leakage of hydraulic fluid from the lock jack assembly, in accordance with the service bulletin.

(i) If no leakage of hydraulic fluid is detected, thereafter, repeat the inspection at intervals not to exceed 30 days, until the requirements of paragraph (b) of this AD are accomplished.

(ii) If any leakage of hydraulic fluid is detected, prior to further flight, replace the lock jack assembly with a new or serviceable unit that does not have one of those serial numbers, in accordance with the service bulletin.

(b) Within 6 months after the effective date of this AD, replace any lock jack assembly having a serial number listed in British Aerospace Inspection Service Bulletin SB 32-103, Revision 1, dated February 22, 1991, with a new or serviceable assembly that does nothave one of those serial numbers, in accordance with the service bulletin.

(c) As of the effective date of this AD, no person shall install a lock jack assembly, having any serial number listed in British Aerospace Inspection Service Bulletin SB 32-103, Revision 1, dated February 22, 1991, on any airplane.

(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 inspections and replacements shall be done in accordance with British Aerospace Inspection Service Bulletin SB 32-103, Revision 1, dated February 22, 1991, which contains the specified list of effective pages:

Page Number
Revision Level
Shown on Page
Date
Shown on Page
1, 2, Appendix A1
Page 1-3
1
February 22, 1991
3, Appendix A1
Page 4
Original
June 15, 1990

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 Holding, Inc., Avro International Aerospace Division, P.O. Box 16039, Dulles International Airport, Washington, DC 20041-6039. 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 March 31, 1997.

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 BAe 146 series airplanes and Model Avro 146-RJ series airplanes was published in the Federal Register on August 27, 1996 (61 FR 44006). That action proposed to require an inspection to identify affected lock jack assemblies by serial number. That action also proposed to require repetitive inspections of certain lock jack assemblies to detect leakage of hydraulic fluid from the lock jack assemblies, and, if leakage is detected, replacement of the lock jack assemblies with new or serviceable assemblies. That action also proposed to require eventual replacement of the lock jack assemblies with new or serviceable assemblies.

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

To accomplish the required inspections will take approximately 1 work hour per airplane, per inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the required inspections on U.S. operators is estimated to be $3,120, or $60 per airplane, per inspection cycle.

To accomplish the required replacement of the lock jack assembly will take approximately 1 work hour per airplane, at an average labor rate of $60 per work hour. Required parts will be provided by the manufacturer at no cost to the operators. Based on these figures, the cost impact of the required replacement on U.S. operators is estimated to be $3,120, or $60 per airplane.

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, positiveor 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: