# AD 2005-07-25: Transformer rectifier units (TRUs) - Type: Airworthiness directive - Status: Current - Products: Airbus A300 B2-1A, A300 B2-1C, A300 B2-203, A300 B2K-3C, A300 B4-103, A300 B4-203, A300 B4-2C, A300 B4-601, A300 B4-603, A300 B4-605R, A300 B4-620, A300 B4-622R and 11 more - Effective: May 16, 2005 - Published: April 11, 2005, 70 FR 18287–18289 - Issued: March 31, 2005 - Issued as: Final rule - Supersedes: [AD 2000-18-07](https://openairdocs.org/ad/2000-18-07) - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Large airplane - Amendment: 39-14050 - Docket: FAA-2004-19227 (https://www.regulations.gov/docket/FAA-2004-19227) - Project: 2003-NM-95-AD - Registered aircraft: 122 may be affected, by airframe or engine model (OpenAirDocs) - Official PDF: https://openairdocs.org/files/sha256/d5/2f/d52fb9705535d6ceb905604e294371e06576a895c1812abd5083fa0e7e533201 (from https://www.govinfo.gov/content/pkg/FR-2005-04-11/pdf/05-6914.pdf) - Federal Register: https://www.federalregister.gov/documents/2005/04/11/05-6914/airworthiness-directives-airbus-model-a300-b2-and-b4-series-airplanes-model-a300-b4-600-a300-b4-600r - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/FF60A5BA290FE0FB86256FE00058B2CB.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/2005-07-25 ## Summary The FAA is superseding an existing airworthiness directive (AD), which applies to certain Airbus Model A300 B2 and B4 series airplanes; Model A300 B4-600, A300 B4-600R, A300 C4-605R Variant F, and A300 F4-600R (collectively called A300-600) series airplanes; and Model A310 series airplanes. That AD currently requires replacement of the transformer rectifier units (TRUs) in the avionics compartment with new, improved TRUs. This new AD requires replacement of the TRUs installed according to the existing AD with different TRUs that are improved. This AD is prompted by analysis that has revealed that certain diodes installed in the TRUs are the main factor contributing to the continuing TRU failures. We are issuing this AD to prevent failure of the TRUs. Failure of multiple TRUs could result in loss of the thrust reversers, autothrottle, flaps, and various systems (wing/cockpit window anti-ice, trim tank pumps, and windshield wipers) on the airplane; or display of incorrect information to the flightcrew. ## The airworthiness directive ### Adoption of the Amendment Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: 1. The authority citation for part 39 continues to read as follows: 2. The FAA amends § 39.13 by removing amendment 39-11892 (65 FR 54407, September 8, 2000), and adding the following new airworthiness directive (AD): 2005-07-25 Airbus: Amendment 39-14050. Docket No. FAA-2004-19227; Directorate Identifier 2003-NM-95-AD. ### (a) Effective Date (a) This AD becomes effective May 16, 2005. ### (b) Affected ADs (b) This AD supersedes AD 2000-18-07, amendment 39-11892 (65 FR 54407, September 8, 2000). ### (c) Applicability (c) This AD applies to Model A300 B2 and B4 series airplanes; Model A300 B4-600, A300 B4-600R, A300 C4-605R Variant F, and A300 F4-600R (collectively called A300-600) series airplanes; and Model A310 series airplanes; certificated in any category; except those on which Airbus Modification 12540 has been accomplished. ### (d) Unsafe Condition (d) This AD was prompted by analysis that has revealed that certain diodes installed in the transformer rectifier units (TRUs) are the main factor contributing to the continuing TRU failures. We are issuing this AD to prevent failure of multiple TRUs, which could result in loss of the thrust reversers, autothrottle, flaps, and various systems (wing/cockpit window anti-ice, trim tank pumps, and windshield wipers) on the airplane; or display of incorrect information to the flightcrew. ### (e) 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. ### (f) Replacement of TRUs (f) Within 36 months after the effective date of this AD, replace the existing TRUs, having P/N F11QY3121, in the avionics compartment with new, improved TRUs having P/N F11QY3714, according to the Accomplishment Instructions of Airbus Service Bulletin A300-24-0099 (for Model A300 B2 and B4 series airplanes), A300-24-6082 (for Model A300-600 series airplanes), or A310-24-2088 (for Model A310 series airplanes); all Revision 01; all dated December 18, 2003; as applicable. Note 1: Airbus Service Bulletins A300-24-0099, A300-24-6082, and A310-24-2088; all Revision 01; refer to Thales Service Bulletin F11QY3121-24-003, dated October 15, 2002, as an additional source of service information for modifying the existing TRUs to the improved configuration. Thales Service Bulletin F11QY3121-24-003 specifies that Auxilec Service Bulletins F11QY3121-24-001, dated February 2, 1998; and F11QY3121-24-002, dated October 5, 2000; must be done to add Amendments A and B, respectively, to P/N F11QY3121 before the TRU can be modified to P/N F11QY3714 according to Thales Service Bulletin F11QY3121-24-003. Note 2: The Accomplishment Instructions of Thales Service Bulletin F11QY3121-24-003 specify to “complete implementation of the [Service Information Letter] SIL F11QY3121-24-004.” This AD does not require doing the service information letter. ### (g) Actions Accomplished Previously (g) Replacements done before the effective date of this AD according to Airbus Service Bulletin A300-24-0099 (for Model A300 B2 and B4 series airplanes), A300-24-6082 (for Model A300-600 series airplanes), or A310-24-2088 (for Model A310 series airplanes); all dated October 11, 2002; as applicable; are acceptable for compliance with the corresponding action required by paragraph (f) of this AD. ### (h) Alternative Methods of Compliance (AMOCs) (h) 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. ### (i) Related Information (i) French airworthiness directive 2003-082R1, dated March 31, 2004, also addresses the subject of this AD. ### (j) Material Incorporated by Reference (j) You must use Airbus Service Bulletin A300-24-0099, Revision 01, dated December 18, 2003; Airbus Service Bulletin A300-24-6082, Revision 01, dated December 18, 2003; or Airbus Service Bulletin A310-24-2088, Revision 01, dated December 18, 2003; as applicable; to perform the actions that are required by this AD; unless the AD specifies otherwise. The Director of the Federal Register approves the incorporation by reference of these documents in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. To get copies of the service information, go to Airbus, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France. To view the AD docket, go to the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, Nassif Building, Washington, DC. To review copies of the service information, go to the National Archives and Records Administration (NARA). For information on the availability of this material at the NARA, call (202) 741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. ## Rule preamble ### Dates This AD becomes effective May 16, 2005. The incorporation by reference of certain publications listed in the AD is approved by the Director of the Federal Register as of May 16, 2005. ### Addresses For service information identified in this AD, contact Airbus, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France. Docket: The AD docket contains the proposed AD, comments, and any final disposition. 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 U.S. Department of Transportation, 400 Seventh Street, SW., room PL-401, Washington, DC. This docket number is FAA-2004-19227; the directorate identifier for this docket is 2003-NM-95-AD. ### For further information contact Tim Backman, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2797; fax (425) 227-1149. ### SUPPLEMENTARY INFORMATION The FAA proposed to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) with an AD to supersede AD 2000-18-07, amendment 39-11892 (65 FR 54407, September 8, 2000). The existing AD applies to certain Airbus Model A300, A300-600, and A310 series airplanes. The proposed AD was published in the Federal Register on October 4, 2004 (69 FR 59153), to require replacement of the transformer rectifier units (TRUs) installed according to the existing AD with different TRUs that are improved. ### Comments We provided the public the opportunity to participate in the development of this AD. We have considered the comments that have been submitted on the proposed AD by a single commenter. ### Request—Correct Typographical Error The commenter notes a typographical error in the citations for one of the service bulletins referenced in the proposed AD. While the preamble of the proposed AD correctly refers to Airbus Service Bulletin A300-24-0099, Revision 01, dated December 18, 2003, the body of the proposed AD incorrectly refers to Airbus Service Bulletin A300-27-0099, Revision 01, dated December 18, 2003. We have revised paragraphs (f) and (g) and Note 1 of this final rule to correct the typographical errors. ### Request—Refer to Corresponding Service Bulletins in Applicability The commenter requests that we revise the applicability statement in paragraph (c) of the proposed AD to refer to the service bulletins that correspond to Airbus Modification 12540—Airbus Service Bulletins A300-24-0099 (for Model A300 B2 and B4 series airplanes), A300-24-6082 (for Model A300-600 series airplanes), and A310-24-2088 (for Model A310 series airplanes); all Revision 01; all dated December 18, 2003. The commenter notes that the applicability of French airworthiness directive 2003-082R1 excludes airplanes on which the relevant service bulletin has been done, but the applicability of the proposed AD does not exclude those airplanes. The commenter states that the exclusion in the French airworthiness directive is intended to minimize the burden on operators that have previously accomplished the relevant service bulletin. The commenter states that it does not understand the explanation of the applicability of the proposed AD that is contained in the paragraph “Difference Between the French Airworthiness Directive and This Proposed AD.” The commenter questions the FAA's concern and wonders whether the stated difference will become a general FAA policy. Our concern about referring in the applicability statement to the service bulletins corresponding to a production modification is the possibility that an airplane modified in service to be equipped with TRUs having part number (P/N) F11QY3714 could subsequently have those TRUs removed and replaced with TRUs having P/N F11QY3121. An operator could misunderstand the intent of an exclusion in the applicability statement and conclude that the airplane is no longer subject to the requirements of this AD because Airbus Service Bulletin A300-24-0099, A300-24-6082, or A310-24-2088, as applicable, was done in the past. We find that not referring to these service bulletins in the applicability statement ensures that all affected airplanes will be equipped with TRUs having P/N F11QY3714. Also, we find this will not place a significant burden on affected operators because, if an airplane has been modified previously to be equipped with TRUs having P/N F11QY3714, according to paragraph (g) of this AD, no further action is required by paragraph (f) of this AD. We have not changed the final rule in this regard. ### Request—Explain Omission of Master Minimum Equipment List (MMEL) Provision The commenter questions why the proposed AD does not mention the MMEL provision specified in French airworthiness directive 2003-082R1. The commenter notes that French airworthiness directive 2003-082R1 specifies that doing the actions in Airbus Service Bulletin A300-24-0099, A300-24-6082, or A310-24-2088, as applicable, is a way to come back to the DGAC's initial MMEL requirements. We find that it is not necessary for this AD to refer to the MMEL provision specified in French airworthiness directive 2003-082R1. The FAA does not issue ADs to mandate changes to the MMEL. Instead, the Chairman of the Flight Operations Evaluation Board, Flight Standards Service, FAA, revises the MMEL; then, operators of U.S.-registered airplanes must comply with the new provisions of the MMEL within 60 days. In this case, the requirements of the FAA's MMEL are already equally restrictive or more restrictive than the DGAC's MMEL provisions. We have not changed the final rule in this regard. ### Explanation of Additional Changes Note 1 of the proposed AD refers to Thales Service Bulletins F11QY3121-24-001, dated February 2, 1998; and F11QY3121-24-002, dated October 5, 2000. We have revised Note 1 in this final rule to refer to these service bulletins as Auxilec service bulletins. Also, a typographical error in paragraph (g) of the proposed AD resulted in an incorrect reference to paragraph (a) of the proposed AD, where we intended to reference paragraph (f) of the proposed AD. We have revised paragraph (g) of this AD to refer to paragraph (f) of this AD. ### Conclusion We have carefully reviewed the available data, including the comments that have been submitted, 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 This AD affects about 165 airplanes of U.S. registry. The new actions take about 2 work hours per airplane, at an average labor rate of $65 per work hour. The parts manufacturer will provide required parts free of charge. Based on these figures, the estimated cost of the new actions required by this AD for U.S. operators is $21,450, or $130 per airplane. ### 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, the FAA is charged 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 AD. ### 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. See the ADDRESSES section for a location to examine the regulatory evaluation. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A35EU](https://openairdocs.org/tcds/A35EU): Airbus SAS; names 16 of 17 models: A310-203, A300 B4-622R, A300 F4-605R, A300 B4-601, A310-204, A310-221, A300 B4-603, A310-324… ## Registered aircraft it may apply to (OpenAirDocs) Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment. - Aircraft: 122 (122 by airframe model, 0 by engine model) - Makers: Airbus Industrie 74, Airbus 48 Models with the most aircraft: - [Airbus Industrie A300 F4-605R](https://openairdocs.org/model/airbus-industrie-a300-f4-605r): 36 aircraft (airframe model) - [Airbus A300 F4-622R](https://openairdocs.org/model/airbus-a300-f4-622r): 31 aircraft (airframe model) - [Airbus Industrie A300 F4-622R](https://openairdocs.org/model/airbus-industrie-a300-f4-622r): 21 aircraft (airframe model) - [Airbus A300 B4-622R](https://openairdocs.org/model/airbus-a300-b4-622r): 11 aircraft (airframe model) - [Airbus Industrie A300 B4-622R](https://openairdocs.org/model/airbus-industrie-a300-b4-622r): 10 aircraft (airframe model) - [Airbus A300 F4-605R](https://openairdocs.org/model/airbus-a300-f4-605r): 6 aircraft (airframe model) - [Airbus Industrie A300 B4-605R](https://openairdocs.org/model/airbus-industrie-a300-b4-605r): 3 aircraft (airframe model) - [Airbus Industrie A310-203](https://openairdocs.org/model/airbus-industrie-a310-203): 2 aircraft (airframe model) - [Airbus Industrie A310-222](https://openairdocs.org/model/airbus-industrie-a310-222): 2 aircraft (airframe model) All 9 models: https://openairdocs.org/ad/2005-07-25/models.md Every aircraft: https://openairdocs.org/ad/2005-07-25/aircraft.md ## Related documents - [AD 2000-18-07](https://openairdocs.org/ad/2000-18-07) (historical): Transformer Rectifier Units (TRU) · Airbus A300-600 Series (all), A300 Series (all) and A310 Series (all). Effective Oct 13, 2000. Replaced by this AD - [Proposed rule FAA-2004-19227](https://openairdocs.org/proposed/FAA-2004-19227): Notice of proposed rulemaking (NPRM), published Oct 4, 2004 Its text cites no advisory circulars or STCs. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.