E6-17661. Airworthiness Directives; Airbus Model A300 B4-600, B4-600R, and F4-600R Series Airplanes, and Model C4-605R Variant F Airplanes (Collectively Called A300-600 Series Airplanes); and Model A310 Series Airplanes

AGENCY:

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

ACTION:

Final rule.

SUMMARY:

The FAA is adopting a new airworthiness directive (AD) for certain Airbus models, as specified above. This AD requires modifying the aft pressure bulkhead for improved corrosion protection and drainage, and related concurrent actions. This AD results from severe corrosion found in the lower rim area of the aft pressure bulkhead during routine maintenance of an airplane. We are issuing this AD to prevent corrosion on the inner rim angle and cleat profile splice of the aft pressure bulkhead, which could result in the loss of airplane structural integrity.

DATES:

This AD becomes effective December 1, 2006.

The Director of the Federal Register approved the incorporation by reference of certain publications listed in the AD as of December 1, 2006.

ADDRESSES:

You may examine the 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., Nassif Building, Room PL-401, Washington, DC.

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

FOR FURTHER INFORMATION CONTACT:

Tom Stafford, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

 

Examining the Docket

You may examine the airworthiness directive (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 street address stated in the ADDRESSES section.

Discussion

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to certain Airbus Model A300 B4-600, B4-600R, and F4-600R series airplanes, and Model C4-605R Variant F airplanes (collectively called A300-600 series airplanes); and Model A310 series airplanes. That NPRM was published in the Federal Register on June 3, 2005 (70 FR 32547). That NPRM proposed to require modifying the aft pressure bulkhead for improved corrosion protection and drainage, and related concurrent actions.

Actions Since NPRM Was Issued

Since we issued the NPRM, Airbus has released Service Bulletin A310-53-2025, Revision 06, dated August 3, 2006. In the NPRM, we referred to Airbus Service Bulletin A310-53-2025, Revision 5, dated March 24, 1989, as the appropriate source of service information for modifying the aft pressure bulkhead to improve the fatigue life of the attachment angles at frame (FR)80/82 on Model A310 series airplanes. The procedures in Revision 06 are essentially the same as those in Revision 5. Therefore, we have revised Table 1 of this AD to refer to Revision 06 as the appropriate source of service information for accomplishing the modification on Model A310 series airplanes. We have also added a new paragraph (k) to this AD, which gives credit for actions accomplished before the effective date of this AD in accordance with Revision 5.

Comments

We provided the public the opportunity to participate in the development of this AD. We have considered the comments received.

Request To Use Alternative Sealant

FedEx requests that we revise the NPRM to identify an alternative to sealant PR-2752 (consumable material list (CML) 09-035), since it is not available from any worldwide source. FedEx states that Airbus has identified an alternative sealant for use on FedEx's airplanes. However, that sealant has an 1,800-flight-cycle life limit, which creates an undue burden on FedEx's operational planning of airplane downtime and resources. FedEx also states that the FAA issued alternative method of compliance (AMOC) letter ANM-116-04-175, dated May 27, 2004, allowing use of that same alternative sealant, which requires repetitively resealing the applicable areas within intervals of 1,800 flight cycles. FedEx asserts that sealant PR-2752, due to its brittleness and low elongation properties, tends to separate from the structure, creating a moisture trap that leads to corrosion. FedEx proposes substituting sealant PR-2752 with an epoxy adhesive like 3M Scotch-Weld EC-2216 to maintain an adequate level of safety and meet design parameters.

We partially agree. Since we issued the NPRM, Airbus has identified another alternative to sealant PR-2752. Sealant MC-650B (CML 09-056), from Chemetall, should be available in December of 2006. Airbus Service Bulletin A310-53-2025, Revision 06, which we described previously, already specifies using MC-650B. Although Airbus Service Bulletin A300-53-6006, Revision 3, dated March 24, 1989, specifies using sealant PR-2752, Airbus does not intend to revise this service bulletin because all affected Model A300-600 series airplanes have been modified already. Airbus has advised us that it does intend to revise Airbus Service Bulletins A300-53-6017 and A310-53-2036, both Revision 02, both dated February 25, 2004, to specify using sealant MC-650B. We have revised paragraph (g) of this AD to allow use of sealant MC-650B as an alternative to sealant PR-2752.

Request To Withdraw NPRM

FedEx requests that we withdraw the NPRM. As justification, FedEx states that, due to the complex structural configuration of the aft pressure bulkhead between FR80 and FR82 and the use of several different compounds for modification of the drain hole, the referenced service bulletins in the NPRM need to identify additional work instructions and substitute materials. In addition, FedEx asserts that removal of sealants, especially sealant PR-2752, could cause more surface protection damage because of the complexity of the joint. FedEx further requests that we coordinate with the Direction Generale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, to ask Airbus to develop a better solution for the application of corrosion-inhibiting compounds and sealants in the discrepant area.

We do not agree to withdraw the NPRM. As stated previously, Airbus has either revised or intends to revise the referenced service bulletins to identify an alternative sealant. Also, the revised service bulletins use specific indicators and criteria to avoid removing the sealant if it is not necessary. These changes should alleviate the complexity of the service bulletins. We have not changed this AD in this regard.

Request To Harmonize Various Service Bulletins and ADs

FedEx requests that we harmonize the modification and inspection programs of several service bulletins and ADs that address corrosion in the aft pressure bulkhead. For Model A300-600 series airplanes, FedEx cites Airbus Service Bulletins A300-53-6006, Revision 3, dated March 24, 1989; A300-53-6017, Revision 02, dated February 25, 2004; and A300-53-6136, dated October 27, 2004. For Model A310 series airplanes, FedEx cites Airbus Service Bulletins A310-53-2025, Revision 5, dated March 24, 1989; A310-53-2036, Revision 02, dated February 25, 2004; and A310-53-2114, dated October 27, 2004. FedEx also cites AD 88-06-03, amendment 39-5871 (53 FR 7730, March 10, 1988), and AD 98-19-22, amendment 39-10763 (63 FR 49656, September 17, 1998).

We disagree and have not revised this AD in this regard. Although the various service bulletins and ADs involve work in the area of the aft pressure bulkhead, they address unsafe conditions related to either corrosion or fatigue. Also, the affected airplanes in the various service bulletins and ADs are different. This AD and AD 88-06-03 both refer to Airbus Service Bulletin A310-53-2025 as the appropriate source of service information for modifying the attachment of the rear pressure bulkhead to FR80/82. This AD requires Revision 06 of that service bulletin, while AD 88-06-03 requires the original issue, dated April 21, 1986, or Revision 3, dated April 7, 1987. However, we specified in the NPRM that paragraph (i) of this AD provides credit for accomplishment of paragraph A.2. of AD 88-06-03. AD 88-06-03 also refers to Airbus Service Bulletin A310-53-2024, Revision 1, dated June 20, 1986; or Revision 3, dated February 17, 1987; as appropriate sources of service information for accomplishing repetitive inspections of the rear pressure bulkhead for cracks. We issued AD 88-06-03 to improve the fatigue life of the attachment angles at FR80/82 on certain Model A310 series airplanes.

AD 98-19-22 refers to Airbus Service Bulletins A300-53-6066 and A310-53-2092, both dated October 16, 1996; and Revision 01, both dated March 11, 1998; as appropriate sources of service information for accomplishing repetitive inspections to detect corrosion of the lower rim area of the aft pressure bulkhead. After we issued AD 98-19-22, severe corrosion was found on certain airplanes that were inspected previously in accordance with that AD. Based on those findings, we determined that the inspection methods in AD 98-19-22 were obsolete and inadequate, and that a new inspection program was necessary. Subsequently, we issued AD 2005-26-16, amendment 39-14437 (70 FR 77307, December 30, 2005), to supersede AD 98-19-22. The inspections required by AD 98-19-22, which refers to Airbus Service Bulletins A300-53-6066 and A310-53-2092, were not retained in AD 2005-26-16. AD 2005-26-16 instead refers to Airbus Service Bulletins A300-53-6136, Revision 01, dated July 18, 2005; and A310-53-2114, Revision 01, dated September 1, 2005; as the appropriate sources of service information for accomplishing the actions in that AD. Further, Airbus has informed us that it issued Airbus Service Bulletins A300-53-6136 and A310-53-2114 to supersede Airbus Service Bulletins A300-53-6066 and A310-53-2092. The table below provides an overview of the ADs we have issued.

AD—	Refers to airbus service bulletin—	Requiring—	Addressing—
88-06-03	A310-53-2024, Revision 1 and Revision 3	Repetitive inspections	Fatigue.
	A310-53-2025, original issue and Revision 3	Modification	Fatigue.
98-19-22 (superseded by AD 2005-26-16)	A300-53-6066, original issue and Revision 01	Repetitive inspections	Corrosion.
	A310-53-2092, original issue and Revision 01	Repetitive inspections	Corrosion.
2005-26-16	A300-53-6136, Revision 01	Repetitive inspections with reduced intervals	Corrosion.
	A310-53-2114, Revision 01	Repetitive inspections with reduced intervals	Corrosion.
This AD	A300-53-6017, Revision 02 A310-53-2036, Revision 02 A300-53-6006, Revision 3 A310-53-2025, Revision 06	Modification Modification Modification Modification	Corrosion. Corrosion. Fatigue. Fatigue.

Request for Credit for Airbus Service Bulletins A300-53-6066 and A310-53-2092

FedEx requests that we give credit for accomplishment of Airbus Service Bulletins A300-53-6066 and A310-53-2092. FedEx states that these service bulletins are referenced in AD 98-19-22 and also involve the lower rim area of the pressure bulkhead.

We disagree. As discussed previously, the repetitive inspections specified in Airbus Service Bulletins A300-53-6066 and A310-53-2092 are obsolete and inadequate for addressing corrosion at the lower rim area of the rear pressure bulkhead. Further, the referenced service bulletins in this AD are intended to not only improve the corrosion protection at the lower rim area of the aft pressure bulkhead, but to also improve the fatigue life of the attachment angles at FR80/82. We have not changed this AD in this regard.

Request To Refer to Airbus Service Bulletins A300-53-6136 and A310-53-2114

FedEx requests that we revise Table 1 of the NPRM to refer to Airbus Service Bulletins A300-53-6136 and A310-53-2114, both dated October 27, 2004, instead of Airbus Service Bulletins A300-53-6006, Revision 3, dated March 24, 1989 (for Model A300-600 series airplanes); and A310-53-2025, Revision 5, dated March 24, 1989 (for Model A310 series airplanes). (In the NPRM, we referred to Airbus Service Bulletins A300-53-6006, Revision 3; and A310-53-2025, Revision 5; as appropriate sources of service information for accomplishing certain related concurrent actions.) As justification, FedEx states that Airbus Service Bulletins A300-53-6136 and A310-53-2114 were issued to address incomplete adhesion of sealant and damage caused to surface protection during cleaning of the drain hole, or during accomplishment of Airbus Service Bulletins A300-53-6006 and A310-53-2025. FedEx states that Airbus Service Bulletins A300-53-6136 and A310-53-2114 also involve inspections for corrosion in the lower rim angle area of the rear pressure bulkhead. FedEx further requests that we coordinate with Airbus and the DGAC to address the apparent discrepancy between Airbus Service Bulletins A300-53-6136 and A300-53-6006 and between Airbus Service Bulletins and A310-53-2025 and A310-53-2114.

We do not agree to refer to Airbus Service Bulletins A300-53-6136 and A310-53-2114 in this AD. As stated previously, AD 2005-26-16 mandates accomplishment of Revision 01 of Airbus Service Bulletins A300-53-6136 and A310-53-2114, as applicable. Airbus has informed us that Airbus Service Bulletins A300-53-6136 and A310-53-2114 were issued to address corrosion prevention, while Airbus Service Bulletins A300-53-6006 and A310-53-2025 were issued to address an unsafe condition caused by fatigue. Airbus has also informed us that Airbus Service Bulletins A300-53-6136 and A310-53-2114 mention accomplishment of 6767yttyyAirbus Service Bulletins A300-53-6006 and A310-53-2025 only as possible sources for corrosion if surface protection is damaged. Airbus states that the service bulletins must be accomplished independently of each other. Therefore, we have not changed this AD in this regard.

Request for Credit for Airbus Service Bulletin A300-53-0218

The Air Transport Association (ATA), on behalf of its member ASTAR Air Cargo (ASTAR), questions the basis of the NPRM since Airbus has issued Service Bulletin A300-53-0218, Revision 02, dated May 10, 2005. ASTAR states that it has accomplished Revision 02 of the service bulletin and intends to use it to show compliance with the proposed requirements of the NPRM. We infer that ASTAR would like us to revise this AD to allow Airbus Service Bulletin A300-53-0218, Revision 02, as an acceptable method of compliance.

We do not agree that Revision 02 of Airbus Service Bulletin A300-53-0218 is acceptable for complying with the requirements of this AD. For Model A300-600 series airplanes, this AD requires accomplishment of Airbus Service Bulletins A300-53-6017, Revision 02; and A300-53-6006, Revision 3. Airbus Service Bulletin A300-53-6017 describes procedures for improving the corrosion protection at the aft pressure bulkhead and enlarging the drainholes for improved drainage. Airbus Service Bulletin A300-53-6006 describes procedures for modifying the aft pressure bulkhead to improve the fatigue life of the attachment angles at FR80/82. Airbus Service Bulletin A300-53-0218 describes procedures for inspecting for corrosion and cracks in the upper rim area of the rear pressure bulkhead aft face, between stringer (STGR) 26 left-hand (LH) and right-hand (RH) and all service apertures, and removing corrosion and repairing as necessary. The service bulletins address different issues; therefore, we have not changed this AD in this regard.

We point out that Airbus Service Bulletin A300-53-218, Revision 1, July 28, 1989, is mandated by AD 90-03-08, amendment 39-6481 (55 FR 1799, January 19, 1990). That AD applies to all Model A300 airplanes. That AD requires repetitive inspections for cracking and corrosion in the lower rim area of the rear pressure bulkhead and adjacent areas, repetitive inspections for cracking or corrosion in the service apertures and the upper rim area of the rear pressure bulkhead, and corrective actions if necessary. We issued AD 90-03-08 to prevent reduced structural capability of the fuselage and subsequent decompression of the airplane. Since we issued AD 90-03-08, we have issued an NPRM to supersede that AD. That NPRM was published in the Federal Register on August 1, 2006 (71 FR 43386). That NPRM refers to Revision 02 of Airbus Service Bulletin A300-53-0218 as the appropriate source of service information for accomplishing certain actions. The procedures in Revision 02 are essentially the same as those in Revision 1, except that Revision 02 reduces the repetitive intervals for the eddy current inspections of the auxiliary power unit (APU) bleed-air line, removes certain airplanes from the inspection of the area between STGR 25 LH and RH, and removes certain airplanes from the inspection of the area between STGR 26 LH and RH.

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.

Conclusion

We have carefully reviewed the available data, including the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We have determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

Costs of Compliance

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

Estimated Costs

Models	Action	Work hours 1	Parts 1	Cost per airplane 1	Number of U.S.- registered airplanes	Fleet cost 1
A300-600 series airplanes	Modification Concurrent Actions 1	34 Between 590 and 660	$1,200 Between $2,442 and $9,884	$3,410 Between $40,792 and $52,784	0 0	$0.
A310 series airplanes	Modification Concurrent Actions 1	34 Between 590 and 660	$1,200 Between $2,442 and $9,884	$3,410 Between $40,792 and $52,784	52 52	$177,320. Between $2,121,184 and $2,744,768.
1 The number of work hours and estimated costs for concurrent actions depend on airplane configuration.

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 AD will not have federalism implications under Executive Order 13132. This AD will 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 this AD:

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

(2) Is not a “significant rule” under 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 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
• Incorporation by reference
• Safety

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 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):

2006-22-03 Airbus: Amendment 39-14800. Docket No. FAA-2005-21343; Directorate Identifier 2004-NM-117-AD.

Effective Date

(a) This AD becomes effective December 1, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Airbus Model A300 B4-600, B4-600R, and F4-600R series airplanes, and Model C4-605R Variant F airplanes (collectively called A300-600 series airplanes); and Model A310 series airplanes; certificated in any category; except those modified in production by Airbus Modification 6788.

Unsafe Condition

(d) This AD results from severe corrosion found in the lower rim area of the aft pressure bulkhead during routine maintenance of an airplane. We are issuing this AD to prevent corrosion on the inner rim angle and cleat profile splice of the aft pressure bulkhead, which could result in the loss of airplane structural integrity.

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 listed in Table 1 of this AD, as applicable:

Table 1.—Service Bulletin References

Models	Requirement	Airbus service bulletin
A300-600 series airplanes	Paragraph (g) of this AD Paragraph (h) of this AD	A300-53-6017, Revision 02, dated February 25, 2004. A300-53-6006, Revision 3, dated March 24, 1989.
A310 series airplanes	Paragraph (g) of this AD Paragraph (h) of this AD	A310-53-2036, Revision 02, dated February 25, 2004. A310-53-2025, Revision 06, dated August 3, 2006.

Modification To Improve Corrosion Protection and Drainage

(g) Within 60 months after the effective date of this AD, modify the aft pressure bulkhead for improved corrosion protection and drainage by doing all of the actions specified in the Accomplishment Instructions of the applicable service bulletin. Where the service bulletin specifies to use sealant PR-2752 (consumable material list (CML) 09-035), sealant MC-650B (CML 09-056) may be used.

Concurrent Modification To Improve Attachment Angles

(h) Before or concurrently with accomplishing the modification required by paragraph (g) of this AD, modify the aft pressure bulkhead to improve the fatigue life of the attachment angles at frame (FR) 80/82 by doing all of the actions specified in the Accomplishment Instructions of the applicable service bulletin. Where the service bulletin specifies doing a visual inspection around the entire circumference between FR80/82 and the aft pressure bulkhead for damaged filler, do a general visual inspection.

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.”

Credit for Concurrent Actions

(i) For Model A310 series airplanes, accomplishment of the actions specified in paragraph A.2. of AD 88-06-03, amendment 39-5871 (53 FR 7730, March 10, 1988), is considered acceptable for compliance with the requirements of paragraph (h) of this AD.

Credit for Previous Service Bulletins

(j) Actions done before the effective date of this AD in accordance with Airbus Service Bulletin A310-53-2036, Revision 01, dated October 9, 2003 (for Model A310 series airplanes), are acceptable for compliance with the requirements of paragraph (g) of this AD.

(k) Actions done before the effective date of this AD in accordance with Airbus Service Bulletin A310-53-2025, Revision 5, dated March 24, 1989 (for Model A310 series airplanes), are acceptable for compliance with the requirements of paragraph (h) of this AD.

Alternative Methods of Compliance (AMOCs)

(l)(1) 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.

(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

(m) French airworthiness directive F-2004-004, dated January 7, 2004, also addresses the subject of this AD.

Material Incorporated by Reference

(n) You must use the applicable service information identified in Table 2 of this AD to perform the actions that are required by this AD, unless the AD specifies otherwise.

Table 2.—Material Incorporated by Reference

Service bulletin	Revision level	Date
Airbus Service Bulletin, A300-53-6006	3	March 24, 1989.
Airbus Service Bulletin, A300-53-6017	02	February 25, 2004.
Airbus Service Bulletin, A310-53-2025	06	August 3, 2006.
Airbus Service Bulletin, A310-53-2036	02	February 25, 2004.

Airbus Service Bulletin, A300-53-6006, Revision 3, dated March 24, 1989, contains the following effective pages:

Page Nos.	Revision level shown on page	Date shown on page
1, 29, 47, 48	3	March 24, 1989.
2-28, 30-46, 49-52	2	August 11, 1988.

The Director of the Federal Register approved the incorporation by reference of these documents in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Contact Airbus, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France, for a copy of this service information. You may review copies at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., Room PL-401, Nassif Building, Washington, DC; on the Internet at http://dms.dot.gov;​; or at the National Archives and Records Administration (NARA). For information on the availability of this material at the NARA, call [phone], or go to http://www.archives.gov/​federal_​register/​code_​of_​federal_​regulations/​ibr_​locations.html.

Issued in Renton, Washington, on October 11, 2006.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.