Airworthiness Directives; British Aerospace Model BAe 146 and Model Avro 146-RJ Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to supersede an existing airworthiness directive (AD) that applies to certain British Aerospace Model BAe 146 and Model Avro 146-RJ series airplanes. The existing AD currently requires a one-time measurement of the thickness of the outer links on the side stays of the main landing gear (MLG), and related investigative and corrective actions as necessary; and provides for replacement of a thin outer link with a new or serviceable part in lieu of certain related investigative inspections. This new proposed AD would instead require repetitive inspections for cracking of the outer links on the MLG side stays, and corrective actions if necessary. This new action would also expand the applicability, provide for optional terminating action for the repetitive inspections, and reduce the repetitive inspection interval. This proposed AD is prompted by new crack findings on airplanes not subject to the existing AD, and the determination that the profile gauge's slipping over the outer link profile is not a factor in the identified unsafe condition. We are proposing this AD to prevent cracking of the outer links of the MLG side stays, which could result in failure of a side stay and consequent collapse of the landing gear.

DATES:

We must receive comments on this proposed AD by January 3, 2005.

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.

For service information identified in this proposed AD, contact British Aerospace Regional Aircraft American Support, 13850 Mclearen Road, Herndon, Virginia 20171.

You can examine the contents of this AD docket on the Internet at http://dms.dot.gov,, or in person at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, on the plaza level of the Nassif Building, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Technical information: Todd Thompson, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-1175; fax (425) 227-1149.

Plain language information: Marcia Walters, marcia.walters@faa.gov.

SUPPLEMENTARY INFORMATION:

Docket Management System (DMS)

The FAA has implemented new procedures for maintaining AD dockets electronically. As of May 17, 2004, new AD actions are posted on DMS and assigned a docket number. We track each action and assign a corresponding directorate identifier. The DMS AD docket number is in the form “Docket No. FAA-2004-99999.” The Transport Airplane Directorate identifier is in the form “Directorate Identifier 2004-NM-999-AD.” Each DMS AD docket also lists the directorate identifier (“Old Docket Number”) as a cross-reference for searching purposes.

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 under ADDRESSES. Include “Docket No. FAA-2004-19757; Directorate Identifier 2001-NM-273-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 our docket 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 can review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you can visit http://dms.dot.gov.

We are reviewing the writing style we currently use in regulatory documents. We are interested in your comments on whether the style of this document is clear, and your suggestions to improve the clarity of our communications that affect you. You can get more information about plain language at http://www.faa.gov/language and http://www.plainlanguage.gov.

Examining the Docket

You can 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 DMS receives them.

Discussion

On August 10, 1999, we issued AD 99-17-12, amendment 39-11260 (64 FR 45870, August 23, 1999), for certain British Aerospace Model BAe 146 and Model Avro 146-RJ series airplanes. That AD requires a one-time measurement to determine the thickness of the outer links of the side stays of the main landing gear (MLG), and corrective actions, if necessary. That AD also provides for replacement of a thin outer link with a new or serviceable part in lieu of certain related investigative inspections. That action was prompted by mandatory continuing airworthiness information that was issued by the Civil Aviation Authority (CAA), which is the airworthiness authority for the United Kingdom. At that time, the CAA had advised that the MLG side stays were susceptible to cracking due to the insufficient thickness of the outer links. We issued that AD to prevent this cracking, which could result in failure of a side stay and consequent collapse of the landing gear.

Actions Since Existing AD was Issued

Since we issued AD 99-17-12, cracks have been found on the outer link shoulders of several MLG side stays. The cracks have been attributed to inadequate greasing, which generated high bearing torque. One of those affected side stays, which had a thicker web, was not subject to AD 99-17-12.

In addition, the existing AD requires certain corrective actions if the profile gauge slips over the top edge of the outer link profile when the link's thickness is measured. We have since determined that the profile gauge's slipping over the outer link profile is not a factor in the identified unsafe condition.

Relevant Service Information

The manufacturer has issued BAE Systems (Operations) Limited Inspection Service Bulletin ISB.32-156, Revision 1, dated July 3, 2001, which describes procedures for repetitive visual inspections for signs of cracks through the paint on the outer link of the MLG side stays. Depending on crack length, corrective actions may include repetitive inspections for cracks of the spherical bearings/greaseways and replacement of the outer link of the MLG side stays with a new or serviceable part. The service bulletin recommends contacting the manufacturer for additional instructions for crack repair. The CAA classified this service bulletin as mandatory and issued British airworthiness directive 004-05-2001 to ensure the continued airworthiness of these airplanes in the United Kingdom.

The optional accomplishment of the actions specified in either Messier-Dowty Limited Service Bulletin 146-32-152, or the combination of Messier-Dowty Limited Repair Scheme 450187952 and Messier-Dowty Limited Service Bulletin 146-32-144, eliminates the need for the repetitive inspections.

Secondary service information references are listed in the following table:

FAA's Determination and Requirements of the Proposed AD

These airplane models are manufactured in France and are type certificated for operation in the United States under the provisions of § 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the DGAC has kept the FAA informed of the situation described above. We have examined the DGAC's findings, evaluated all pertinent information, and determined that AD action is necessary for airplanes of this type design that are certificated for operation in the United States.

This proposed AD would supersede AD 99-17-12 to require repetitive inspections for cracks of the outer links on the MLG side stays. The proposed AD would also expand the applicability and provide for optional terminating action for the repetitive inspections. The actions would be required to be accomplished in accordance with BAE Systems (Operations) Limited Inspection Service Bulletin ISB.32-156, described previously, except as discussed under “Differences Between Proposed AD and Service Bulletin.”

Differences Between Proposed AD and Service Bulletin

The applicability of the British airworthiness directive specifies “side stays as listed in Messier-Dowty Service Bulletin 146-32-145.” We have determined, in conjunction with the CAA and the manufacturer, that Messier-Dowty Service Bulletin 146-32-147 properly lists all the affected side stays by serial number and/or part number. Therefore, this proposed AD refers to Service Bulletin 146-32-147 for the additional information regarding the applicability.

Unlike the procedures described in Service Bulletin ISB.32-156, this proposed AD would not permit further flight if cracks are detected in a flange. We have determined that, because of the safety implications and consequences associated with such cracking, any cracked flange must be repaired or modified before further flight.

Service Bulletin ISB.32-156 recommends contacting the manufacturer for instructions on how to repair certain conditions, but this proposed AD would require repairing those conditions using a method approved by the FAA or the CAA (or its delegated agent). In light of the type of repair that would be required to address the unsafe condition, and consistent with existing bilateral airworthiness agreements, we have determined that, for this proposed AD, a repair approved by the FAA or the CAA would be acceptable for compliance with this proposed AD.

The Accomplishment Instructions of Messier-Dowty Service Bulletin 146-32-147 describe procedures for reporting the inspection findings to the manufacturer; however, this proposed AD would not require a report.

Costs of Compliance

The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

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. 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.