On March 24, 1995, the FAA issued priority letter AD 95-07-04, which currently requires the following on certain Mooney Model M20R airplanes:
o repetitively inspecting the exhaust system for cracks;
o replacing the exhaust system if any cracks are found; and
o reporting to the FAA any cracks found. Accomplishment of this action is in accordance with section 5 and section 81 of the Mooney Model M20R Service and Maintenance Manual (section 78 in Service and Maintenance Manual revisions issued after April 1995).
Several (13) reports of exhaust system cracks on the affected airplanes prompted priority letter AD 95-07-04. The service time of the airplanes with cracks found was as low as 8 hours time-in-service. Investigation of the cracked exhaust systems revealed that these cracks formed in the exhaust header assembly, the muffler assembly, and the exhaust tailpipe assembly, specifically at the spot welds.
The exhaust system header assembly on the Model M20R airplanes is located near the fuel lines. The high temperatures emanating from exhaust system cracks could cause an airplane fire with this close proximity to the fuel lines.
Mooney issued Service Bulletin M20-257, Revision A, dated March 21, 1995, which references repetitive inspections of the exhaust system on the affected Model M20R airplanes. The exhaust system on the affected airplanes consists of the following parts:
o Exhaust Header Assembly: part number 630079-501/-502
o Muffler Assembly: part number 630088-501; and
o Exhaust Tail Pipe Assembly: part number 630087-501/-502
Since the FAA issued priority letter AD 95-07-04, Mooney has developed an exhaust system modification that, when incorporated, would eliminate the need for the repetitive inspections required by the current AD. Mooney issued Instructions-Retrofit Kit, part number (P/N) 940095-501-1, dated March 31, 1995, and Special Letter 95-1, dated April 20, 1995, which specify instructions for incorporating this exhaust system modification on Mooney Model M20R airplanes. In addition, Mooney incorporated the instructions of both the above documents in Instructions-Retrofit Kit, P/N 940095-501-1, Revised April 21, 1995. This modification is referenced in Mooney Service Bulletin M20-257, Revision B, dated April 5, 1995.
After examining the circumstances and reviewing all available information related to the accidents described above, the FAA has determined that the modification described above should be incorporated on certain Mooney Model M20R airplanes, and that AD action should be taken in order to prevent an airplane engine fire that could result from exhaust system cracks.
Since an unsafe condition has been identified that is likely to exist or develop in other Mooney M20R airplanes of the same type design, this AD supersedes priority letter AD 95-07-04 with a new AD that (1) retains the requirement of repetitively inspecting the exhaust system for cracks until the exhaust system is modified; and (2) requires modifying the exhaust system if cracks are found and at a certain time period if cracks aren't found. This exhaust system modification eliminates the repetitive inspection requirement. Accomplishment of the exhaust system modification is in accordance with either (1) Mooney Instructions-Retrofit Kit, P/N 940095-501-1, Revised April 21, 1995; or (2) both Mooney Instructions-Retrofit Kit, P/N 940095-501-1, dated March 31, 1995, and Mooney Special Letter 95-1, dated April 20, 1995.
Since a situation exists (possible exhaust leaks near the fuel lines) that requires the immediate adoption of this regulation, it is found that notice and opportunity for public prior 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 immediate flight safety and, thus, was not preceded by notice and opportunity to 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 should identify the Rules Docket number and be submitted in triplicate to the address specified above. 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 notice must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket No. 95-CE-24-AD." The postcard will be date stamped and returned to the commenter.
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 and that must be issued immediately to correct an unsafe condition in aircraft, and 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 (otherwise, an evaluation is not required). A copy of it, if filed, may be obtained from the Rules Docket.
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. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89.
Section 39.13 - [AMENDED]
2. Section 39.13 is amended by adding a new airworthiness directive to read as follows: