Airworthiness Directives; AeroSpace Technologies of Australia Pty Ltd. Models N22B, N22S, and N24A Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for all AeroSpace Technologies of Australia Pty Ltd. (ASTA) Models N22B, N22S, and N24A airplanes. This proposed AD would require you to repetitively inspect wing fittings for fatigue defects, replace or correct defective wing fittings, and replace the stub wing front spar assembly and wing fitting when fatigue life limits are reached. This proposed AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Australia. We are issuing this proposed AD to detect and correct defects in the wing strut upper end fittings, wing strut lower end fittings, stub wing strut pick up fittings, and the stub wing front spar assembly. These defects could result in failure of the fittings or spar assembly and lead to reduced structural capability or reduced controllability of the airplane.

DATES:

We must receive any comments on this proposed AD by December 4, 2003.

ADDRESSES:

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

• By mail: FAA, Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 2003-CE-37-AD, 901 Locust, Room 506, Kansas City, Missouri 64106.
• By fax: (816) 329-3771.
• By e-mail: 9-ACE-7-Docket@faa.gov. Comments sent electronically must contain “Docket No. 2003-CE-37-AD” in the subject line. If you send comments electronically as attached electronic files, the files must be formatted in Microsoft Word 97 for Windows or ASCII.

You may get the service information identified in this proposed AD from Nomad Operations, Aerospace Support Division, Boeing Australia, PO Box 767, Brisbane, QLD 4000 Australia; telephone 61 7 3306 3366; facsimile 61 7 3306 3111.

You may view the AD docket at FAA, Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 2003-CE-37-AD, 901 Locust, Room 506, Kansas City, Missouri 64106. Office hours are 8 a.m. to 4 p.m., Monday through Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT:

Ron Atmur, Aerospace Engineer, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712; telephone (562) 627-5224; facsimile (562) 627-5210.

SUPPLEMENTARY INFORMATION:

Comments Invited

How do I comment on this proposed AD? We invite you to submit any written relevant data, views, or arguments regarding this proposal. Send your comments to an address listed under ADDRESSES. Include “AD Docket No. 2003-CE-37-AD” in the subject line of your comments. If you want us to acknowledge receipt of your mailed comments, send us a self-addressed, stamped postcard with the docket number written on it. We will date-stamp your postcard and mail it back to you.

Are there any specific portions of this proposed AD I should pay attention to? We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. If you contact us through a nonwritten communication and that contact relates to a substantive part of this proposed AD, we will summarize the contact and place the summary in the docket. We will consider all comments received by the closing date and may amend this proposed AD in light of those comments and contacts.

Discussion

What events have caused this proposed AD? The Civil Aviation Safety Authority (CASA), which is the airworthiness authority for Australia, recently notified FAA that an unsafe condition may exist on all ASTA Models N22B, N22S, and N24A airplanes. The CASA reports that fatigue tests on the wing strut upper end fitting have shown premature failures and rapid crack growth. Also, fatigue tests on the wing strut lower end fittings, stub wing strut pick up fitting, and stub wing front spar assembly have identified appropriate fatigue lives for the respective parts.

What are the consequences if the condition is not corrected? Fatigue loading could result in failure of the wing strut upper end fitting, wing strut lower end fittings, stub wing strut pick up fitting, or stub wing front spar assembly. Such failure could lead to reduced structural capability or reduced controllability of the airplane.

Is there service information that applies to this subject? Boeing Australia (formerly ASTA) Aerospace Technologies of Australia has issued:

—Nomad Alert Service Bulletin No. ANMD-57-12, Revision 2, dated May 25, 1999;

—Nomad Service Bulletin No. NMD-53-18, dated February 8, 1996; and

—Nomad Service Bulletin No. NMD-53-18, Revision 1, dated September 3, 2002.

What are the provisions of this service information? The service bulletins include procedures for:

—Performing a fatigue inspection of the stub wing strut pick-up fittings for cracks;

—Replacing the stub wing strut pick-up fittings;

—Inspecting (visually) the strut to upper strut fittings bolt holes for scoring, ovality, fretting, corrosion, and dimensions;

—Inspecting (eddy current method) the strut to upper strut fittings bolt holes for cracks;

—Modifying (line ream) the strut to upper strut fitting bolt holes;

—Replacing bolts for the strut upper end fittings; and

—Replacing the strut upper end fittings.

What action did the CASA take? The CASA classified these service bulletins as mandatory and issued these Australian ADs in order to ensure the continued airworthiness of these airplanes in Australia:

—AD Number AD/GAF-N22/2, Amendment 3, dated January 28, 2003; and

—AD Number AD/GAF-N22/70, Amendment 2, dated January 28, 2003.

FAA's Determination and Requirements of This Proposed AD

What has FAA decided? We have examined the CASA's findings, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Since the unsafe condition described previously is likely to exist or develop on other ASTA Models N22B, N22S, and N24A airplanes of the same type design that are registered in the United States, we are proposing AD action to detect and correct defects in the wing strut upper end fittings, wing strut lower end fittings, stub wing strut pick up fittings, and the stub wing front spar assembly. These defects could result in failure of the fittings or spar assembly and lead to reduced structural capability or reduced controllability of the airplane.

What would this proposed AD require? This proposed AD would require you to incorporate the actions in the previously-referenced service bulletin.

How does the revision to 14 CFR part 39 affect this proposed AD? On July 10, 2002, we published a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs FAA's AD system. This regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance. This material previously was included in each individual AD. Since this material is included in 14 CFR part 39, we will not include it in future AD actions.

Costs of Compliance

How many airplanes would this proposed AD impact? We estimate that this proposed AD affects 15 airplanes in the U.S. registry.

What would be the cost impact of this proposed AD on owners/operators of the affected airplanes? We estimate the following costs to accomplish the proposed inspection of the wing strut upper end fitting bolt holes:

We estimate the following costs to accomplish the proposed inspection of the stub wing strut pick up fittings:

We estimate the following costs to accomplish any necessary replacements of the wing strut upper end fittings that would be required based on the results of the proposed inspection or on reaching the fatigue life limit. We have no way of determining the number of airplanes that may need such replacement:

We estimate the following costs to accomplish any necessary replacements of the wing strut lower end fittings that would be required based on reaching the fatigue life limit. We have no way of determining the number of airplanes that may need such replacement:

We estimate the following costs to accomplish any necessary replacements of the stub wing strut pick up fittings that would be required based on the results of the proposed inspection or on reaching the fatigue life limit. We have no way of determining the number of airplanes that may need such replacement:

We estimate the following costs to accomplish any necessary replacements of the stub wing front spar assembly that would be required based on reaching the fatigue life limit. We have no way of determining the number of airplanes that may need such replacement:

Regulatory Findings

Would this proposed AD impact various entities? 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.

Would this proposed AD involve a significant rule or regulatory action? For the reasons discussed above, I certify that this proposed AD:

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 summary of the costs to comply with this proposed AD and placed it in the AD Docket. You may get a copy of this summary by sending a request to us at the address listed under ADDRESSES. Include “AD Docket No. 2003-CE-37-AD” in your request.

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 Federal Aviation Administration 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.