05-1809. Airworthiness Directives; Aerospatiale Model ATR42-200, -300, and -320 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 Aerospatiale Model ATR42-200, -300, and -320 series airplanes. This proposed AD would require doing repetitive inspections of the upper arms of the MLG side braces for missing or inadequately bonded identification plates; replacing the upper arm if necessary; and replacing the side brace assembly with a modified part. This proposed AD is prompted by an operator who reported experiencing an unlock warning for the MLG on the right side of the airplane. We are proposing this AD to prevent cracking of the upper arms of the side braces of the MLG, which could result in failure of the MLG during landing and possible damage to the airplane and injury to the flightcrew and passengers.

DATES:

We must receive comments on this proposed AD by March 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.
• By fax: [phone].
• 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 Messier-Dowty, BP 10, 78142 Velizy Cedex, France.

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. This docket number is FAA-2005-20220; the directorate identifier for this docket is 2004-NM-152-AD.

FOR FURTHER INFORMATION CONTACT:

Tom Rodriguez, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

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 under ADDRESSES. Include “Docket No. FAA-2005-20220; Directorate Identifier 2004-NM-152-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 submitted 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.

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 [phone]) 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

The Direction Générale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, notified us that an unsafe condition may exist on certain Aerospatiale Model ATR42-200, -300, and -320 series airplanes. The DGAC advises that an operator reported experiencing, during taxiing, an unlock warning for the MLG on the right side of the airplane. Investigation found that the upper side brace of the right MLG was cracked due to accidental damage caused by the location of certain identification plates and possible corrosion introduced during production. Cracking of the upper arms of the side braces of the MLG, if not corrected, could result in failure of the MLG during landing and possible damage to the airplane and injury to the flightcrew and passengers.

Relevant Service Information

Messier-Dowty has issued Special Inspection Service Bulletin 631-32-175, dated January 7, 2004; and Service Bulletin 631-32-176, Revision 1, dated June 2, 2004. Special Inspection Service Bulletin 631-32-175 describes procedures for doing repetitive general visual inspections of the upper arms of the MLG side braces for missing or inadequately bonded identification plates having P/Ns D61565-1, D61566-1, D61567-1, and D61568-1; and replacing any upper arm having a missing or inadequately-bonded identification plate with a serviceable upper arm having the same part number. Service Bulletin 631-32-176 describes procedures for removing the side brace assembly and replacing it with a modified part. Modification of the side brace assembly includes the following actions:

• Removing and discarding identification plates with P/Ns D61565-1, D61566-1, D61567-1, and D61568-1;
• Inspecting and restoring the side brace assembly;
• Installing identification plates, with P/Ns D61565-1, D61566-1, D61567-1, and D61568-1, in a new location; and
• Reidentifying the modified side brace assembly.

Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition. The DGAC mandated the service information and issued French airworthiness directive F-2004-006, dated January 7, 2004, to ensure the continued airworthiness of these airplanes in France.

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 findings, evaluated all pertinent information, and determined that we need to issue an AD for products of this type design that are certificated for operation in the United States.

Therefore, we are proposing this AD, which would require accomplishing the actions specified in the service information described previously, except as discussed under “Difference Between the Proposed AD and French Airworthiness Directive.”

Difference Between the Proposed AD and French Airworthiness Directive

Operators should note that, although the French airworthiness directive recommends accomplishing the replacement of the side brace assemblies at the next overhaul, we have determined that a specific compliance time is needed to ensure that the identified unsafe condition is addressed in a timely manner. In developing an appropriate compliance time for this proposed AD, we considered not only the manufacturer's recommendation, but also the degree of urgency associated with addressing the subject unsafe condition, and the average utilization of the affected fleet. Considering these factors, this proposed AD requires replacement before the accumulation of 15,000 total flight cycles on a side brace assembly or 96 months on a side brace assembly since new, whichever occurs first. We find that this compliance time is warranted, in that it represents an appropriate interval of time allowable for affected airplanes to continue to operate without compromising safety.

Costs of Compliance

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

Estimated Costs

Action	Work hours	Average labor rate per hour	Parts	Cost per airplane	Number of U.S.-registered airplanes	Fleet cost
Inspection, per inspection cycle	1	$65	None	$65	7	$455, per inspection cycle.
Replacement of side brace assemblies	2	65	0	130	7	$910.

Authority for This Rulemaking

The FAA's authority to issue rules regarding aviation safety is found in Title 49 of the United States Code. 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.

This rulemaking is promulgated 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 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.

§ 39.13

[Amended]

2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD):

Aerospatiale: Docket No. FAA-2005-20220; Directorate Identifier 2004-NM-152-AD.

Comments Due Date

(a) The Federal Aviation Administration must receive comments on this AD action by March 3, 2005.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Aerospatiale Model ATR42-200, -300, and -320 series airplanes with main landing gear (MLG) side brace assemblies, part number (P/N) D22710000-7, equipped with upper arms having P/N D56778-10, serial numbers MN 566 through MN 581 inclusive; certificated in any category.

Unsafe Condition

(d) This AD was prompted by an operator who reported experiencing an unlock warning for the MLG on the right side of the airplane. We are issuing this AD to prevent cracking of the upper arms of the side braces of the MLG, which could result in failure of the MLG during landing and possible damage to the airplane and injury to the flightcrew and passengers.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Service Bulletin References

(f) The term “service bulletin,” as used in this AD, means the Accomplishment Instructions of the following service bulletins, as applicable:

(1) For the repetitive inspections and replacements specified in paragraphs (g) and (h) of this AD, respectively: Messier-Dowty Special Inspection Service Bulletin 631-32-175, dated January 7, 2004; and

(2) For the replacements specified in paragraph (i) of this AD: Messier-Dowty Service Bulletin 631-32-176, Revision 1, dated June 2, 2004.

Repetitive Inspections of Identification Plates

(g) Within 2 months or 500 flight hours after the effective date of this AD, whichever occurs first: Do a general visual inspection of the upper arms of the MLG side braces for missing or inadequately bonded identification plates having P/Ns D61565-1, D61566-1, D61567-1, and D61568-1, in accordance with the service bulletin. Thereafter at intervals not to exceed 2 months or 500 flight hours, whichever occurs first: Repeat the inspection of the upper arm of the MLG side brace for any side brace assembly that has not been replaced as required by paragraph (i) of this AD.

Note 1:

For the purposes of this AD, a general visual inspection is: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to ensure visual access to all surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”

Replacement of Upper Arms, If Necessary

(h) If any identification plate, P/N D61565-1, D61566-1, D61567-1, or D61568-1, is found missing or inadequately bonded during any inspection required by paragraph (g) of this AD: Within 25 flight hours since the most recent inspection, replace any upper arm having a missing or inadequately bonded identification plate with a serviceable upper arm having the same part number, in accordance with the service bulletin.

Replacement With Modified Side Brace Assemblies

(i) Before the accumulation of 15,000 total flight cycles on a side brace assembly or 96 months on a side brace assembly since new, whichever occurs first: Remove the side brace assembly and replace it with a part modified by doing all of the actions in the service bulletin. Replacement of a side brace assembly with a modified part terminates the repetitive inspections required by paragraph (g) of this AD for that modified side brace assembly only. If both side brace assemblies of the MLG are replaced with modified parts, no more work is required by paragraph (g) of this AD.

Credit for Previous Service Bulletin

(j) Replacements done before the effective date of this AD in accordance with Messier-Dowty Service Bulletin 631-32-176, dated February 26, 2004, is acceptable for compliance with the corresponding requirements of paragraph (i) of this AD.

Alternative Methods of Compliance (AMOCs)

(k) The Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

Related Information

(l) French airworthiness directive F-2004-006, dated January 7, 2004, also addresses the subject of this AD.

Issued in Renton, Washington, on January 21, 2005.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.