The Direction Generale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, notified the FAA that an unsafe condition may exist on certain Airbus Model A318, A319, A320, and A321 series airplanes. The DGAC advises that an Airbus Model A340 series airplane lost the integrated standby instrument system (ISIS), then, during the same flight, lost all electronic instrument system (EIS) display units. Investigation revealed that the ISIS failure is caused by a time-counter fault that occurs after 145 hours of continuous power supply to the ISIS. Loss of the ISIS, if combined with loss of all EIS display units, could reduce the flightcrew's situational awareness and contribute to loss of control of the airplane or impact with obstacles or terrain.
The subject ISIS on certain Airbus Model A340 series airplanes is also installed on certain Airbus Model A318, A319, A320, and A321 series airplanes. Therefore, airplanes of all of these models may be subject to the identified unsafe condition.
The DGAC has issued French Emergency Airworthiness Directive UF- 2004-168, dated October 20, 2004, to ensure the continued airworthiness of these airplanes in France.
FAA's Determination and Requirements of This AD
These airplane models are manufactured in France and are type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. According to this bilateral airworthiness agreement, the DGAC has kept us informed of the situation described above. We have examined the DGAC's 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 issuing this AD to prevent loss of the ISIS, which, if combined with loss of all EIS display units, could reduce theflightcrew's situational awareness and contribute to loss of control of the airplane or impact with obstacles or terrain. This AD requires regularly performing a complete electrical shutdown of the airplane to reset the ISIS.
Differences Between the AD and French Emergency Airworthiness Directive
This AD differs from the French Emergency Airworthiness Directive in that this AD does not allow resetting the circuit breaker as a means of resetting the ISIS. This AD instead requires a complete electrical shutdown of the airplane, which the French Emergency Airworthiness Directive provides as an alternative means of resetting the ISIS. The decision to not allow resetting the circuit breaker is based on FAA policy that pulling circuit breakers is not an acceptable means of routinely removing electrical power from airplane systems. This policy is based on the fact that use of a circuit breaker as a switch will degrade the ability of the circuit breaker to trip at its rated current trip point.
Interim Action
We consider this AD interim action. We are currently considering requiring the installation of an upgraded ISIS standard, which would eliminate the need to regularly perform a complete electrical shutdown of the airplane. However, the planned compliance time for this installation would allow enough time to provide notice and opportunity for public comment on the merits of the modification.
FAA's Determination of the Effective Date
An unsafe condition exists that requires the immediate adoption of this AD; therefore, providing notice and opportunity for public comment before the AD is issued is impracticable, and good cause exists to make this AD effective in less than 30 days.
Comments Invited
This AD is a final rule that involves requirements that affect flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any relevant written data, views, or arguments regarding this AD. Send your comments to an address listed under ADDRESSES. Include "Docket No. FAA-2004-19817; Directorate Identifier 2004-NM-237-AD" at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the AD. We will consider all comments received by the closing date and may amend the 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 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.
We are reviewing the writing style we currently use in regulatory documents. We are interested in your comments on whether the style of this document is clear, and your suggestions to improve the clarity of our communications with you. You can get more information about plain language at http://www/faa.gov/language and http://www.plainlanguage.gov.
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 the 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 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.
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 FAA amends 39.13 by adding the following new airworthiness directive (AD):