E6-4406. Airworthiness Directives; Airbus Model A300 B2 and A300 B4 Series Airplanes; and Model A300 B4-600, B4-600R, and F4-600R Series Airplanes, and Model C4-605R Variant F Airplanes (Collectively Called A300-600 Series Airplanes)

AGENCY:

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

ACTION:

Supplemental notice of proposed rulemaking (NPRM); reopening of comment period.

SUMMARY:

The FAA is revising an earlier supplemental NPRM for an airworthiness directive (AD) that applies to certain Airbus airplanes as listed above. The first supplemental NPRM would have required repetitively inspecting for cracking in the web of nose rib 7 of the inner flap on the wings, and performing related investigative/corrective actions if necessary. The original NPRM resulted from reports of cracking in the web of nose rib 7 of the inner flap. This action revises the first supplemental NPRM by requiring eventual replacement of nose rib 7 with a new, improved rib, which would terminate the proposed inspections. This action also removes from the applicability airplanes on which the improved nose rib 7 was installed during production. We are proposing this supplemental NPRM to prevent cracking in the web of nose rib 7, which could result in rupture of the attachment fitting between the inner flap and flap track 2, and consequent reduced structural integrity of the flap.

DATES:

We must receive comments on this supplemental NPRM by April 21, 2006.

ADDRESSES:

Use one of the following addresses to submit comments on this supplemental NPRM.

• 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: [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.

Contact Airbus, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France, for service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT:

Thomas Stafford, 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 supplemental NPRM. Send your comments to an address listed in the ADDRESSES section. Include the docket number “Docket No. FAA-2004-19566; Directorate Identifier 2004-NM-72-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this supplemental NPRM. We will consider all comments received by the closing date and may amend this supplemental NPRM in light of those comments.

We will post all comments submitted, 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 supplemental NPRM. 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 the 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 [phone]) is located on the plaza level in the Nassif Building at the DOT street address stated in ADDRESSES. Comments will be available in the AD docket shortly after the Docket Management System receives them.

Discussion

We proposed to amend 14 CFR part 39 with a supplemental notice of proposed rulemaking (NPRM) for an airworthiness directive (AD) (the “first supplemental NPRM”). The first supplemental NPRM applies to all Airbus Model A300 B2 and A300 B4 series airplanes; and Model A300 B4-600, B4-600R, and F4-600R series airplanes, and Model C4-605R Variant F airplanes (collectively called A300-600 series airplanes). The first supplemental NPRM was published in the Federal Register on September 15, 2005 (70 FR 54486). The first supplemental NPRM proposed to require repetitively inspecting for cracking in the web of nose rib 7 of the inner flap on the wings, and performing related investigative/corrective actions if necessary.

The first supplemental NPRM specified that, if any cracking is found, nose rib 7 must be replaced with a reinforced rib having increased flange thickness and new shape. However, subsequent flight testing of this reinforced rib revealed that further reinforcement of nose rib 7 was necessary.

Relevant Service Information

Since the preparation of the first supplemental NPRM, Airbus has issued Service Bulletins A300-57-0245 (for Model A300 B2 and B4 series airplanes) and A300-57-6100 (for Model A300-600 series airplanes), both Revision 01, dated March 9, 2006. These service bulletins state that they supersede Airbus Service Bulletins A300-57-0242 and A300-57-6097, respectively, both dated December 18, 2003. (The first supplemental NPRM referred to Airbus Service Bulletins A300-57-0242 and A300-57-6097 as the acceptable source of service information for the proposed related investigative and corrective actions.)

Airbus Service Bulletins A300-57-0245 and A300-57-6100 describe procedures for replacing nose rib 7 with a new, improved rib. This is the corrective action if any crack is found in the vertical stiffeners or the horizontal flanges of nose rib 7. But, in addition, the service bulletin recommends eventual replacement of nose rib 7 on all airplanes, regardless of whether cracking is found.

Among other things, the new, improved rib has an increased web thickness, thicker vertical stiffeners in a modified position, radius instead of chamfer on hinge lug edges, and thicker lug bases. The procedures for the replacement include doing related investigative and corrective actions if necessary. The related investigative actions include an inspection for any damage of the bearing assembly of the lug of nose rib 7, and high-frequency eddy current inspections or detailed visual inspections, as applicable, to detect cracking in fastener holes and in the upper radii of the skin flanges of the ribs and front spar. If any damage or cracking is found during these inspections, the service bulletins specify contacting Airbus.

Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition. The Direction Générale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, mandated the service information and issued French airworthiness directive F-2005-198, dated December 7, 2005, to ensure the continued airworthiness of these airplanes in France. The effectivity of French airworthiness directive F-2005-198 excludes airplanes on which the new service information or the related production modifications have been done.

FAA's Determination and Proposed Requirements of the Supplemental NPRM

The changes discussed above expand the scope of the original NPRM; therefore, we have determined that it is necessary to reopen the comment period to provide additional opportunity for public comment on this supplemental NPRM.

Clarification of Inspection Terminology

In this supplemental NPRM, the “detailed visual inspection”' specified in Airbus Service Bulletins A300-57-0245 and A300-57-6100 is referred to as a “detailed inspection.” We have included the definition for a detailed inspection in a note in this supplemental NPRM.

Differences Among the Supplemental NPRM, French Airworthiness Directive, and Relevant Service Information

Unlike the procedures described in the service information and French airworthiness directive, this supplemental NPRM would not permit further flight if any crack is detected in nose rib 7 of the inner flap. We have determined that, because of the safety implications and consequences associated with that cracking, the nose rib must be replaced and all applicable related investigative/corrective actions must be done before further flight after the crack finding.

The service information specifies that you may contact the manufacturer for instructions on how to repair certain conditions, but this supplemental NPRM would require you to repair those conditions using a method that we or the DGAC (or its delegated agent) approve. 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 that we or the DGAC approve would be acceptable for compliance with this proposed AD.

The applicability of the French airworthiness directive excludes airplanes on which Airbus Service Bulletin A300-57-0245 or A300-57-6100 was accomplished in service. However, we have not excluded those airplanes in the applicability of this supplemental NPRM; rather, this supplemental NPRM includes a requirement to accomplish the actions specified in the applicable service bulletin. This requirement would ensure that the actions specified in the applicable service bulletin and that would be required by this proposed AD are accomplished on all affected airplanes. Operators must continue to operate the airplane in the configuration required by this proposed AD unless an alternative method of compliance (AMOC) is approved.

Also, the service information and the French airworthiness directive specify reporting inspection findings to Airbus. This supplemental NPRM would not require that action.

These differences have been coordinated with the DGAC.

Explanation of Removal of Interim Action

In the first supplemental NPRM, we explain that we considered the action interim because the manufacturer was currently developing a modification that would address the unsafe condition identified in this AD. As we explained previously, since we prepared the first supplemental NPRM, Airbus has developed a new, improved nose rib 7. Installing the new, improved rib is intended to adequately address the unsafe condition. Thus, this second supplemental NPRM is no longer considered interim action.

Clarification of AMOC Paragraph

We have revised this action to clarify the appropriate procedure for notifying the principal inspector before using any approved AMOC on any airplane to which the AMOC applies.

Costs of Compliance

The following table provides the estimated costs for U.S. operators to comply with this supplemental NPRM, at an average labor rate of $65 per hour.

Estimated Costs

Action	Work hours	Parts	Cost per airplane	Number of U.S.-registered airplanes	Fleet cost
Inspection, per inspection cycle	3	None	$195	143	$27,885, per inspection cycle.
Rib replacement	10	$10,980	11,630	143	$1,663,090.

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 supplemental NPRM 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.

§ 39.13

[Amended]

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

Airbus: Docket No. FAA-2004-19566; Directorate Identifier 2004-NM-72-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by April 21, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Airbus Model A300 B2-1A, B2-1C, B2K-3C, B2-203, B4-2C, B4-103, B4-203, B4-601, B4-603, B4-605R, B4-620, B4-622, B4-622R, F4-605R, F4-622R, and C4-605R Variant F airplanes; certificated in any category; except those on which Airbus Modification 13031 or 19575 was accomplished in production.

Unsafe Condition

(d) This AD was prompted by reports of cracking in the web of nose rib 7 of the inner flap. We are issuing this AD to prevent cracking in the web of nose rib 7, which could result in rupture of the attachment fitting between the inner flap and flap track 2, and consequent reduced structural integrity of the flap.

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.

Inspections

(f) Do a detailed inspection, using a borescope or endoscope, for cracking of the vertical stiffeners, and of the horizontal flanges between the stiffeners, of nose rib 7 of the inner flap of the left- and right-hand wings; and do an eddy current inspection to detect cracking in the horizontal flanges of the attachment lug root of nose rib 7 of the inner flap of the left- and right-hand wings; in accordance with the Accomplishment Instructions of Airbus Service Bulletin A300-57-0240 or A300-57-6095, both Revision 01, both dated December 2, 2004, as applicable. Do the initial inspections at the applicable compliance time specified in paragraph (f)(1) or (f)(2) of this AD.

Note 1:

For the purposes of this AD, a detailed inspection is: “An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required.”

(1) For airplanes on which nose rib 7 has not been replaced in accordance with Airbus Service Bulletin A300-57-0242 or A300-57-6097, both dated December 18, 2003: Do the initial inspections at the applicable time specified in paragraph (f)(1)(i) or (f)(1)(ii) of this AD.

(i) For airplanes with 18,599 or fewer total flight cycles as of the effective date of this AD: Prior to the accumulation of 5,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever is later.

(ii) For airplanes with 18,600 or more total flight cycles as of the effective date of this AD: Within 500 flight cycles after the effective date of this AD.

(2) For airplanes on which nose rib 7 has been replaced in accordance with Airbus Service Bulletin A300-57-0242 or A300-57-6097, both dated December 18, 2003: Do the initial inspection within 5,000 flight cycles after accomplishing the replacement, or within 1,000 flight cycles after the effective date of this AD, whichever is later.

No Crack Found: Repetitive Inspections

(g) If no crack is found during the inspection required by paragraph (f) of this AD: Repeat the inspection at intervals not to exceed 1,000 flight cycles, until the terminating action in paragraph (i) of this AD is completed.

Crack Found: Related Investigative/Corrective Actions

(h) If any crack is found during any inspection required by paragraph (f) or (g) of this AD: Before further flight, replace nose rib 7 with a new, improved rib and do all related investigative actions and applicable corrective actions in accordance with the Accomplishment Instructions of Airbus Service Bulletin A300-57-0245, Revision 01, or A300-57-6100, Revision 01, both dated March 9, 2006, as applicable, except as provided by paragraph (j) of this AD. This terminates the repetitive inspections required by paragraph (g) of this AD for the modified flaps only.

Terminating Action

(i) Within 5,000 flight cycles or 36 months after the effective date of this AD, whichever is first: Replace nose rib 7 with a new, improved rib and do all related investigative actions and applicable corrective actions in accordance with the Accomplishment Instructions of Airbus Service Bulletin A300-57-0245, Revision 01, or A300-57-6100, Revision 01, both dated March 9, 2006, as applicable, except as provided by paragraph (j) of this AD. This terminates the repetitive inspections required by paragraph (g) of this AD.

Repairing Per the FAA or Direction Générale de l'Aviation Civile (DGAC)

(j) If any crack or damage is found for which the applicable service bulletin specifies to contact Airbus: Before further flight, repair per a method approved by either the Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA; or the Direction Generale de l'Aviation Civile (DGAC) (or its delegated agent).

No Reporting Required

(k) Airbus Service Bulletins A300-57-0240 and A300-57-6095, both Revision 01, both dated December 2, 2004, specify to submit certain information to the manufacturer, but this AD does not include that requirement.

Actions Accomplished in Accordance With Initial Issue of Service Bulletins

(l) Actions done before the effective date of this AD in accordance with Airbus Service Bulletin A300-57-0245 or A300-57-6100, both dated August 31, 2005, are acceptable for compliance with the requirements of paragraphs (h) and (i) of this AD.

Alternative Methods of Compliance (AMOCs)

(m)(1) The Manager, International Branch, ANM-116, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

(2) Before using any AMOC approved in accordance with 14 CFR 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

Related Information

(n) French airworthiness directive F-2005-198, dated December 7, 2005, also addresses the subject of this AD.

Issued in Renton, Washington, on March 14, 2006.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.