Airworthiness Directives; Lockheed Model 1329 Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for certain Lockheed Model 1329 series airplanes. This proposed AD would require determining the part number on the steering cylinder assembly for the nose landing gear (NLG), determining the total flight cycles accumulated on the NLG steering cylinder assembly, repetitive replacement of the assembly, inspecting for missing tow turning limit markings, and performing corrective actions if necessary. This proposed AD results from reports of numerous failures of the NLG steering cylinder. We are proposing this AD to prevent the loss of hydraulic pressure and steering control.

DATES:

We must receive comments on this proposed AD by June 25, 2007.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD.

• DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
• Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• Mail: Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590.
• Fax: (202) 493-2251.
• Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Contact Lockheed Martin Aircraft & Logistics Center, 120 Orion Street, Greenville, South Carolina 29605, for the service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT:

Hector Hernandez, Aerospace Engineer, Systems and Equipment Branch, ACE-119A, FAA, Atlanta Aircraft Certification Office, One Crown Center, 1895 Phoenix Boulevard, Suite 450, Atlanta, Georgia 30349; telephone (770) 703-6069; fax (770) 703-6097.

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any relevant written data, views, or arguments regarding this proposed AD. Send your comments to an address listed in the ADDRESSES section. Include the docket number “FAA-2007-28255; Directorate Identifier 2007-NM-023-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://dms.dot.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of that Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov.

Examining the Docket

You may examine the AD docket on the Internet at http://dms.dot.gov,, or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone (800) 647-5227) is located on the plaza level of the Nassif Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the Docket Management System receives them.

Discussion

We have received reports of numerous failures of the nose landing gear (NLG) steering cylinder on Lockheed Model 1329 series airplanes. These failures have been attributed to stress corrosion cracking, compounded by towing of the aircraft and exceeding the allowable turn limits with the scissor links connected. The manufacturer has reviewed service history and performed structural analysis on the cylinder assembly. Failure of the steering cylinder, if not corrected, could result in the loss of hydraulic pressure and steering control.

Relevant Service Information

We have reviewed the Lockheed service bulletins identified in the following table.

The service bulletins describe procedures for the following actions:

• Inspecting the NLG steering cylinder assembly for the installed part number;
• Removing from service NLG steering cylinder assemblies, part number (P/N) JL1955-1 and JL1955-3;
• Reviewing airplane records to determine the total flight cycles accumulated on the cylinder assembly;
• Removing from service those cylinders that have exceeded their life limit;
• Establishing life limits (including a repetitive replacement schedule) for all other part-numbered cylinder assemblies (as set forth in the Life Limits table below);
• Replacing, with new parts, any cylinder assembly if its part number is JL1955-1 or JL1955-3 or its components' life limits have been exceeded;
• Inspecting the exterior fuselage to confirm that the tow turning limit markings are present on the airplane; and
• Restoring/applying the markings.

Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other airplanes of this same type design. For this reason, we are proposing this AD, which would require accomplishing the actions specified in the service information described previously.

We have determined that a reliable inspection of the subject area is not possible. Because the initial detectable crack is longer than the critical crack length in this case, we cannot show crack growth using damage tolerance analysis or develop appropriate inspection intervals. Further, disassembling the actuator steering cylinder—the only possible way to perform the inspection—would destroy the cylinder. As a result of service history and engineering evaluation, a fatigue-based life limit of the actuator steering cylinder is necessary to ensure the continued airworthiness of the fleet.

Costs of Compliance

There are about 48 airplanes of the affected design in the worldwide fleet. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, 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 have determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would 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 that the proposed regulation:

1. Is not a “significant regulatory action” under Executive Order 12866;

2. Is not a “significant rule” under the 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 proposed AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

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