AD 99-06-12

This amendment adopts a new airworthiness directive (AD) that applies to all British Aerospace HP137 Mk1, Jetstream series 200, and Jetstream Models 3101 and 3201 airplanes. This AD requires replacing the nose wheel steering jack seals with seals of an improved design. This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for the United Kingdom. The actions specified by this AD are intended to prevent the nose landing gear steering from locking up due to deterioration of the original design nose landing gear steering jack seals, which could result in reduced or loss of control of the airplane during takeoff, landing, and taxi operations.

Final rule

99-06-12 BRITISH AEROSPACE: Amendment 39-11076, Docket No. 98-CE-102-AD.
Applicability: HP137 Mk1, Jetstream Series 200, and Jetstream Models 3101 and 3201 airplanes, all serial numbers, certificated in any category; that incorporate the following:

Steering Jack Type: 618200.

Nose Gear Type: 1873, B00A702852A, B00A703056A; or B00A703064A.

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 (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 within the next 9 calendar months after the effective date of this AD, unless already accomplished.

To prevent the nose landing gear steering from locking up due to deterioration of the original design nose landing gear steering jack seals, which could result in reduced or loss of control of the airplane during takeoff, landing, and taxi operations, accomplish the following:

(a) Replace the nose wheel steering jack seals with seals of improved design, in accordance with Jetstream Service Bulletin 32-JA900942, Original Issue: October 22, 1990, Revision No. 5: September 4, 1998, and the instructions in APPH Ltd. Service Bulletin 32-51, which incorporates the following pages:

Pages
Revision Level
Date
1 and 2
Revision 5
April 1996
3
Original Issue
January 1993
4, 5, and 6
Revision 4
October 1993

(b) As of the effective date ofthis AD, no person may install, on any of the affected airplanes, any landing gear steering jack seal that is not of the improved design referenced in the service information specified in paragraph (a) of this AD, or an FAA-approved equivalent.

(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) An alternative method of compliance or adjustment of the compliance time that provides an equivalent level of safety may be approved by the Manager, Small Airplane Directorate, Aircraft Certification Service, 1201 Walnut, suite 900, Kansas City, Missouri 64106. The request shall be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Small Airplane Directorate.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Small Airplane Directorate.

(e) Questions or technical information related to the service information referenced in this document should be directed to British Aerospace Regional Aircraft, Prestwick International Airport, Ayrshire, KA9 2RW, Scotland; telephone: (01292) 479888; facsimile: (01292) 479703. This service information may be examined at the FAA, Central Region, Office of the Regional Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106.

(f) The replacements required by this AD shall be done in accordance with Jetstream Service Bulletin 32-JA900942, Original Issue: October 22, 1990, Revision No. 5: September 4, 1998, and APPH Ltd. Service Bulletin 32-51, which incorporates the following pages:

Pages
Revision Level
Date
1 and 2
Revision 5
April 1996
3
Original Issue
January 1993
4, 5, and 6
Revision 4
October 1993

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, Prestwick International Airport, Ayrshire, KA9 2RW, Scotland. Copies may be inspected at the FAA, Central Region, Office of the Regional Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, 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 Aerospace Jetstream Service Bulletin 32-JA900942, Original Issue: October 22, 1990, Revision No. 5: September 4, 1998. This service bulletin is classified as mandatory by the United Kingdom Civil Aviation Authority (CAA).

(g) This amendment becomes effective on April 26, 1999.

Events Leading to the Issuance of This AD
A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to all British Aerospace HP137 Mk1, Jetstream series 200, and Jetstream Models 3101 and 3201 airplanes was published in the Federal Register as a notice of proposed rulemaking (NPRM) on December 22, 1998 (63 FR 70700). The NPRM proposed to require replacing the nose wheel steering jack seals with seals of improved design. Accomplishment of the proposed action as specified in the NPRM would be in accordance with Jetstream Service Bulletin 32-JA900942, Original Issue: October 22, 1990, Revision No. 5: September 4, 1998, and the instructions in APPH Ltd. Service Bulletin 32-51, which incorporates the following pages:

Pages
Revision Level
Date
1 and 2
Revision 5
April 1996
3
Original Issue
January 1993
4, 5, and 6
Revision 4
October 1993

The NPRM was the result of mandatorycontinuing airworthiness information (MCAI) issued by the airworthiness authority for the United Kingdom.

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposed rule or the FAA's determination of the cost to the public.

The FAA's Determination
After careful review of all available information related to the subject presented above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed except for minor editorial corrections. The FAA has determined that these minor corrections will not change the meaning of the AD and will not add any additional burden upon the public than was already proposed.

Compliance Time of This AD
The unsafe condition referenced in this AD is not a result of repetitive airplane operation. The nose wheel steering jack seals deteriorate over time due to weather and climate conditions. For this reason, the FAA has determined that a compliance based on calendar time instead of hours time-in-service (TIS) should be utilized in this AD in order to assure that the unsafe condition is addressed on all airplanes in a reasonable time period.

Cost Impact
The FAA estimates that 250 airplanes in the U.S. registry will be affected by this AD, that it will take approximately 12 workhours per airplane to accomplish this action, and that the average labor rate is approximately $60 an hour. Parts cost approximately $220 per airplane. Based on these figures, the total cost impact of this AD on U.S. operators is estimated to be $235,000, or $940 per airplane.

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 thisfinal 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 copy of the final evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting 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 a new airworthiness directive (AD) to read as follows: