The Direction Generale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, recently notified the FAA that an unsafe condition may exist on certain Dassault Model Mystere-Falcon 50 series airplanes. The DGAC advises that since September 2002, there have been four separate reports of interference and consequent chafing on the hydraulic lines located within the No. 1 and No. 3 engine pylons. The interference and consequent chafing were discovered during scheduled maintenance. In a recent occurrence (April 9, 2003), the No. 1 hydraulic system failed due to leakage of the hydraulic line where chafing had worn through the hydraulic line. The No. 1 and No. 3 engine pylon installations are symmetrical. Subsequent investigation of the No. 3 engine pylon revealed that the hydraulic lines of the No. 2 hydraulic system were also chafed severely. Such chafing and consequent leakage of the hydraulic lines located within the No. 1 and No. 3 enginepylons, if not corrected, can result in failure of the No. 1 and No. 2 hydraulic systems, and consequent reduced controllability of the airplane.
Explanation of Relevant Service Information
Dassault has issued Service Bulletin F50-A370, dated May 6, 2003, which describes procedures for a detailed inspection for clearance and chafing of the entire length of the hydraulic lines located within the engine pylons, and follow-on/corrective actions, as applicable. The follow-on actions include fastening the hydraulic clamps, ensuring proper clearance between the hydraulic lines and adjacent structure, and using yellow paint to mark the location of the clamps installed on the hydraulic lines. The corrective actions include inspecting for discrepancies (i.e., evidence of contact, chafing, or abrasion) between the hydraulic lines, measuring the wear depth, and replacing the hydraulic line with a new hydraulic line, as applicable.
Dassault has issued Falcon 50 Maintenance Manual Temporary Revision 37, dated May 2003, which describes procedures for ensuring that the clamps that hold the hydraulic lines are reinstalled in their initial position during normal maintenance, and that the position is identified with a yellow paint line. Accomplishment of the actions specified in the service bulletin and the maintenance manual temporary revision are intended to adequately address the identified unsafe condition.
The DGAC classified this service bulletin and maintenance manual temporary revision as mandatory and issued French telegraphic airworthiness directive T2003-190(B), dated May 6, 2003, to ensure the continued airworthiness of these airplanes in France.
FAA's Conclusions
This airplane model is manufactured in France and is type certificated for operation in the United States under the provisions of Sec. 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 Requirements of Rule
Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design registered in the United States, this AD is being issued to prevent chafing and consequent leakage of the hydraulic lines located within the No. 1 and No. 3 engine pylons, which can result in failure of the No. 1 and No. 2 hydraulic systems, and consequent reduced controllability of the airplane. This AD requires a detailed inspection
for clearance and chafing of the entire length of the hydraulic lines within the pylons, and follow-on/corrective actions, as applicable. This AD also requires a revision of the maintenance manual to ensure that the clamps that hold the hydraulic lines are reinstalled in their initial position during normal maintenance, and that the position is identified with a yellow paint line. The actions are required to be accomplished in accordance with the service bulletin and maintenance manual temporary revision described previously.
Difference Between This AD and French Airworthiness Directive
Operators should note that the French telegraphic airworthiness directive specifies that the required actions be accomplished within the next 3 flights from the date of receipt of the French telegraphic airworthiness directive. The compliance time for this AD is within 7 days of the effective date of this AD.
We have determined that the identified unsafe condition is not a catastrophic event based on the following information:
There is no indication that two hydraulic systems will fail simultaneously. The event that occurred on April 9, 2003, was a single system failure.The Falcon 50 Airplane Flight Manual contains procedures for single and dual hydraulic systems failure.
Model Mystere-Falcon 50 series airplanes are certified for manual reversion of the flight control system with the loss of the No. 1 and No. 2 hydraulic systems.
Model Mystere-Falcon 50 series airplanes have an electric auxiliary hydraulic system in the event that No. 1 and No. 2 hydraulic systems fail.
In light of all of these factors, we find a 7-day compliance time for completing the required actions to be warranted, in that it represents an appropriate interval of time allowable for affected airplanes to continue to operate without compromising safety.
Changes to 14 CFR Part 39/Effect on the AD
On July 10, 2002, the FAA issued a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs the FAA's airworthiness directives system. The regulation now includes material that relates to altered products, special flight permits, and alternative methods ofcompliance (AMOC). Because we have now included this material in part 39, only the office authorized to approve AMOCs is identified in each individual AD.
Determination of Rule's Effective Date
Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.
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.
Submit comments using the following format:
Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
For each issue, state what specific change to the AD is being requested.
Include justification (e.g., reasons or data) for each request.
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 2003-NM-118-AD." The postcard will be date stamped and returned to the commenter.
Regulatory Impact
The regulations adopted herein 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. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132.
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: