AD 2007-21-17

We are adopting a new airworthiness directive (AD) for the products listed above. This AD results from mandatory continuing airworthiness information (MCAI) issued by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:

There has been a report of landing gear radius rods suffering cracks starting in the flashline near the microswitch boss. Such cracks can result in loss of the normal hydraulic system and may lead to a landing gear collapse. Main landing gear collapse is considered as potentially hazardous/ catastrophic. This AD mandates additional inspections considered necessary to address the identified unsafe condition.

Note: The cause of this cracking is not related to previous cracking of the radius rod cylinder addressed by BAE Systems SB 32- JA040945 (CAA AD G-2005-0010), however, the consequences of a failure are the same.

We are issuing this AD to requireactions to correct the unsafe condition on these products.

Final Rule.

2007-21-17 British Aerospace Regional Aircraft: Amendment 39-15235; Docket No. FAA-2007-28115; Directorate Identifier 2007-CE-045-AD.

Effective Date

(a) This airworthiness directive (AD) becomes effective November 28, 2007.

Affected ADs

(b) None.

Applicability

(c) This AD applies to HP.137 Jetstream Mk.1, Jetstream Series 200, Jetstream Series 3101, and Jetstream Model 3201 airplanes, all serial numbers, certificated in any category.

(d) Air Transport Association of America (ATA) Code 32: Landing Gear.

Reason

(e) The mandatory continuing airworthiness information (MCAI) states:

There has been a report of landing gear radius rods suffering cracks starting in the flashline near the microswitch boss. Such cracks can result in loss of the normal hydraulic system and may lead to a landing gear collapse. Main landing gear collapse is considered as potentially hazardous/catastrophic. This AD mandates additional inspections considered necessary to address the identified unsafe condition.

Note: The cause of this cracking is not related to previous cracking of the radius rod cylinder addressed by BAE Systems SB 32- JA040945 (CAA AD G-2005-0010), however, the consequences of a failure are the same.

Actions and Compliance

(f) Unless already done, do the following actions:

(1) Initially within the next 3 months after November 28, 2007 (the effective date of this AD) and repetitively thereafter at intervals not to exceed 12 months until the replacement required by paragraph (f)(2) or (f)(3) of this AD is done, inspect the main landing gear radius rod forged cylinder flashline following the accomplishment instructions of British Aerospace Jetstream Series 3100 and 3200 Service Bulletin 32-JA060741, dated November 1, 2006.

(2) If cracks are found during any inspection required by this AD, before further flight, replace the radius rod assembly with a serviceable unit.

(i) If the radius rod assembly includesthe parts described in paragraphs (f)(3)(i) and (f)(3)(ii) of this AD, then the repetitive inspections of this AD are no longer required.

(ii) If the radius rod assembly does not include the parts described in paragraphs (f)(3)(i) and (f)(3)(ii) of this AD, then continue to repetitively inspect at intervals not to exceed 12 months until you comply with paragraph (f)(3) of this AD.

(3) Upon reaching 8,000 total landings on the main landing gear radius rods or within the next 12 months November 28, 2007(the effective date of this AD), whichever occurs later, replace the radius rod assembly by installing one of the following part numbers (P/N). This terminates the repetitive inspection requirement of this AD:

(i) P/N 1847/A to 1847/L with strike-off 12 or 13, or 1847/M or later; and

(ii) P/N 1862/A to 1862/L with strike-off 12 or 13, or 1862/M or later.

(4) For airplanes under 8,000 total landings on the main landing gear radius rods: Before further flight afterthe initial inspection required by paragraph (f)(1) of this AD, do not install a radius rod assembly that is not one of the parts specified in paragraphs (f)(3)(i) and (f)(3)(ii) of this AD on an affected airplane, unless it has been inspected in accordance with paragraph (f)(1) of this AD.

(5) For those airplanes with parts listed in paragraph (f)(3) of this AD: Before further flight after installing the parts in paragraphs (f)(3)(i) and (f)(3)(ii) of this AD, do not install any radius rod assembly that does not incorporate the parts in paragraphs (f)(3)(i) and (f)(3)(ii) of this AD.

Note 1: When a compliance time in this AD is presented in landings and you do not keep the total landings, you may multiply the total number of airplane hours time-in-service by 0.75 to calculate the number of landings for the purposes of doing the actions required by this AD.

Note 2: Maintenance procedures for each radius rod overhaul are included in APPH Service Bulletin 1847-32-12 or 1862-32-12, both dated September 2006, as applicable. You may do such maintenance using the above referenced bulletins or through a fluorescent dye penetrant inspection of the cylinder counterbore as specified in APPH Component Maintenance Manual (CMM) 32-10-16 at Revision 11 or higher.

FAA AD Differences

Note 3: This AD differs from the MCAI and/or service information as follows:

(1) The MCAI and service bulletin allow the radius rod assembly to be repetitively inspected for the life of the airplane and the repetitive inspection requirement is terminated if improved design parts are installed. Many of the affected airplanes are used in commuter operations (14 CFR part 135). The FAA's policy on aging commuter class aircraft states that when a modification exists that could eliminate or reduce the number of required critical inspections, the modification should be incorporated. Therefore, the FAA is mandating the replacement of the radius rod assembly with improved design parts no later than reaching 8,000 total landings on the main landing gear radius rods or within the next 12 months after the effective date of this AD, whichever occurs later.

(2) The MCAI includes a reference to APPH service bulletins as an option for maintenance overhaul procedures. Because we do not require general maintenance in our ADs, we added a note referencing these bulletins as an option to use for overhaul procedures.

Other FAA AD Provisions

(g) The following provisions also apply to this AD:

(1) Alternative Methods of Compliance (AMOCs): The Manager, Standards Staff, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Taylor Martin, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: (816) 329-4138; fax: (816) 329-4090. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.

(2) Airworthy Product: For any requirement in this AD to obtain corrective actions from a manufacturer or other source, use these actions if they are FAA-approved. Corrective actions are considered FAA-approved if they are approved by the State of Design Authority (or their delegated agent). You are required to assure the product is airworthy before it is returned to service.

(3) Reporting Requirements: For any reporting requirement in this AD, under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.), the Office of Management and Budget (OMB) has approved the information collection requirements and has assigned OMB Control Number 2120-0056.

Related Information

(h) Refer to European Aviation Safety Agency (EASA) AD No. 2007- 0087, dated March 30, 2007; and BAE SYSTEMS Jetstream Series 3100 and 3200 Service Bulletin 32-JA060741, dated November 1, 2006; for related information.

Material Incorporated by Reference

(i) You must use BAE SYSTEMS Jetstream Series 3100 and 3200 Service Bulletin 32-JA060741, dated November 1, 2006 to do the actions required by this AD, unless the AD specifies otherwise.

(1) The Director of the Federal Register approved the incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51.

(2) For service information identified in this AD, contact British Aerospace (Operations) Limited Trading at British Aerospace Regional Aircraft, Prestwick International Airport, Ayrshire KA9 2RW, Scotland.

(3) You may review copies at the FAA, Central Region, Office of the Regional Counsel, 901 Locust, Room 506, Kansas City, Missouri 64106; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to the specified products. That NPRM was published in the Federal Register on July 6, 2007 (72 FR 36914). That NPRM proposed to correct an unsafe condition for the specified products. The MCAI states:

There has been a report of landing gear radius rods suffering cracks starting in the flashline near the microswitch boss. Such cracks can result in loss of the normal hydraulic system and may lead to a landing gear collapse. Main landing gear collapse is considered as potentially hazardous/catastrophic. This AD mandates additional inspections considered necessary to address the identified unsafe condition.

Note: The cause of this cracking is not related to previous cracking of the radius rod cylinder addressed by BAE Systems SB 32- JA040945 (CAA AD G-2005-0010), however, the consequences of a failure are the same.

CommentsWe gave the public the opportunity to participate in developing this AD. We considered the comment received.

Comment Issue: Compliance Time

APPH, the original equipment manufacturer of the main landing gear of the affected airplanes, expresses concern over being able to supply the necessary parts for the mandatory replacement. APPH understands the FAA's policy on aging commuter class aircraft, but states that all airplanes will have accumulated 8,000 total landings. Therefore, the proposed AD would require the replacement on all airplanes within 100 hours time-in-service (TIS) after the effective date of the AD. APPH recommends a compliance time of "at the next scheduled overhaul.''

The FAA partially concurs. We understand the problem with supplying parts for all airplanes within 100 hours TIS. However, the airplanes may not have "scheduled overhauls,'' since the overhaul program is a recommended overhaul program and not a mandatory overhaul program. The FAA has determined that changing the 100-hour TIS grace period to 12 months would eliminate the repetitive inspections and provide additional time for operators to acquire the needed parts.

We are changing the mandatory replacement compliance time in the final rule AD action to read "upon reaching 8,000 total landings on the main landing gear radius rods or within the next 12 months after the effective date of this AD, whichever occurs later.''

Conclusion

We reviewed the available data, including the comment received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We determined that these changes will not increase the economic burden on any operator or increase the scope of the AD.

Differences Between This AD and the MCAI or Service Information

We have reviewed the MCAI and related service information and, in general, agree with their substance. But we might have found it necessary to use different wordsfrom those in the MCAI to ensure the AD is clear for U.S. operators and is enforceable. In making these changes, we do not intend to differ substantively from the information provided in the MCAI and related service information.

We might also have required different actions in this AD from those in the MCAI in order to follow FAA policies. Any such differences are highlighted in a note within the AD.

Costs of Compliance

We estimate that this AD will affect 190 products of U.S. registry. We also estimate that it will take about 14 work-hours per product to comply with basic requirements of this AD. The average labor rate is $80 per work-hour. Required parts will cost about $10,000 per product.

Based on these figures, we estimate the cost of this AD to the U.S. operators to be $2,112,800 or $11,120 per product.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section106, describes the authority of the FAA Administrator. "Subtitle VII: Aviation Programs,'' describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in "Subtitle VII, Part A, Subpart III, Section 44701: General requirements.'' Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

We determined that this AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect 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.

For the reasons discussed above, I certify this AD

(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.

We prepared a regulatory evaluation of the estimated costs to comply with this AD and placed it in the AD Docket.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov ; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains the NPRM, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (telephone (800) 647-5527) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 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.

Sec. 39.13 [Amended]

2. The FAA amends Sec. 39.13 by adding the following new AD: