On July 14, 1998, the FAA issued telegraphic AD T98-15-51, which is applicable to all Airbus Model A319, A320, A321, A300, A310, A300-600, A330, and A340 series airplanes.
The Direction G n rale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, notified the FAA that an unsafe condition may exist on all Airbus Model A319, A320, A321, A300, A310, A300-600, A330, and A340 series airplanes. The DGAC advises that it received a report indicating a Model A320 series airplane overran the end of the runway upon landing. Investigation revealed that this event was attributed to the freezing of water that entered the bottom of the braking dual distribution valve (BDDV) during flight, which resulted in the failure of both the normal and alternate modes of the braking system upon landing.
Subsequent investigation revealed that the normal braking system was lost at touchdown due to a malfunction of the brake steering control unit (BSCU) at autobrake selection in flight. Airplane and laboratory tests indicate that the absence of braking on the alternate braking system resulted from seizure of the alternate BDDV. Reports indicate this seizing of the BDDV was caused by the freezing of 33 cubic centimeters of water found in the BDDV cover located at the bottom of the BDDV. The manufacturer indicated that the freezing occurred during flight and that there was insufficient time between the end of the flight and the landing for the ice to melt. The manufacturer also indicated that the rubber sealant normally applied to the junction area of the BDDV body and the cover was missing. In addition, a significant concentration of detergent was found in the water that was removed from the BDDV cover. Because the reasons for the missing sealant and existence of water in the BDDV are not yet determined, further analyses, tests, and investigations are being conducted.
These conditions, if not corrected, could result in failure of the alternate braking system, which could result in the airplane overrunning the end of the runway during landing.
Similar Airplane Models
The BSCU and BDDV installed on Model A320 series airplanes are similar in design to the BSCU and BDDV installed on Model A319, A320, A300, A310, A300-600, A330, and A340 series airplanes; therefore, the FAA finds that all such airplanes are subject to the same unsafe condition identified in this AD.
Explanation of Relevant Service Information
Airbus has issued All Operator Telex (AOT) 32-19, dated July 7, 1998, which describes procedures for in-flight operational checks of the alternate braking system by the flight crew, and replacement of the BDDV with a serviceable part, if necessary.
The AOT references the following Flight Operation Telexes (FOT s) as additional sources of service information: FOT 999.0062 (for Model A300 series airplanes), FOT 999.0061 (for Model A300-600 and A310 series airplanes), FOT 999.059 (for Model A319, A320, and A321 series airplanes), and FOT 999.0060 (for Model A330 and A340 series airplanes); all dated July 7, 1998.
The DGAC classified the AOT as mandatory and issued French airworthiness directives T98-263-120 (B), T98-263-255(B), T98-263-075(B), and T98-263-092(B), all dated July 8, 1998, in order to assure the continued airworthiness of these airplanes in France.
FAA's Conclusions
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. Pursuant to this bilateral airworthiness agreement, the DGAC has kept the FAA informed of the situation described above. The FAA has examined the findings of the DGAC, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.Explanation of the Requirements of the Rule
Since the unsafe condition described is likely to exist or develop on other airplanes of the same type design registered in the United States, the FAA issued telegraphic AD T98-15-51 to prevent failure of the alternate braking system, which could result in the airplane overrunning the end of the runway upon landing. The AD requires an initial and repetitive in-flight operational checks of the alternate braking system, and replacement of the BDDV with a serviceable part, if necessary. This AD also requires that operators report to the manufacturer any findings of the initial operational check and findings of any defective BDDV parts for the repetitive operational checks. The actions are required to be accomplished in accordance with the AOT described previously.
This is considered to be interim action until final action is identified, at which time the FAA may consider further rulemaking.
Since it was found that immediate corrective action was required, notice and opportunity for prior public comment thereon were impracticable and contrary to the public interest, and good cause existed to make the AD effective immediately by individual telegrams issued on July 14, 1998, to all known U.S. owners and operators of all Airbus Model A319, A320, A321, A300, A310, A300-600, A330, and A340 series airplanes. These conditions still exist, and the AD is hereby published in the Federal Register as an amendment to section 39.13 of the Federal Aviation Regulations (14 CFR 39.13) to make it effective as to all persons.
Comments Invited
Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified under the caption ADDRESSES. All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.
Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: Comments to Docket Number 98-NM-229-AD. The postcard will be date stamped and returned to the commenter.
Regulatory Impact
The regulations adopted herein will not have substantial direct effects 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. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.
The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a significant regulatory action under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, may be obtained from the Rules Docket at the location provided under the caption ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new airworthiness directive: