On June 20, 2003, the FAA issued an Emergency AD (EAD) 2003-13-51 for the specified MDHI model helicopters that contained interim actions until certain investigations were complete. That EAD reuqires certain checks and inspections of bolt, part number (P/N) 900R3100001-103, replacing the bolt with an airworthy bolt if necessary. That action was prompted by two instances of failure of a bolt.
Since the issuance of that EAD, we have new information that indicates that the pilot check and torque inspection required by the EAD can be limited to certain bolts. We also determined that disassembly and a more detailed inspection of the condition of each bolt is necessary. On July 2, 2003, we superseded EAD 2003-13-51 by issuing EAD 2003-14-51, which requires certain checks and inspections of certain bolts and replacing any bolt with an airworthy bolt if necessary. The EAD also provides terminating action for the requirements of the EAD.
The FAA has reviewedMD Helicopters Service Bulletin SB900-092R1, dated June 30, 2003 (SB), which describes procedures for disassembling and inspecting the bolts.
Since the unsafe condition described is likely to exist or develop on other MDHI helicopters of the same type design, the FAA issued EAD 2003-14-51 to prevent failure of a bolt, loss of a main rotor blade, and subsequent loss of control of the helicopter. The AD requires the following:
Before further flight, remove, inspect, and reinstall each bolt, unless accomplished previously. If segments do not move freely or a crack is found, replace the bolt with an airworthy bolt before further flight.
Thereafter, until the terminating action is accomplished, before each start of the engines for each bolt with 400 or more hours TIS, do a visual check. A pilot may perform the visual check.
If a bolt has shifted upward or if there is no gap between the thrust washer and retainer (the gap indicates that the O ring is intact), before furtherflight, inspect the bolt.
At specified intervals, until you accomplish the terminating action, for bolts with 400 or more hours TIS, do a cam lever force inspection on each bolt, without removing the bolt.
Within 30 days, for bolts with 400 or more hours TIS, disassemble, inspect, and reinstall each airworthy bolt. If a crack, fretting, or corrosion is found, replace the bolt with an airworthy bolt before further flight.
Before accumulating 400 hours TIS, for each bolt with less than 400 hours TIS, disassemble, inspect, and reinstall each airworthy bolt. If a crack, fretting, or corrosion is found, replace the bolt with an airworthy bolt before further flight.
Doing the required disassembly and inspections of each bolt, P/N 900R3100001-103, constitutes terminating action for the requirements of this AD. The actions must be accomplished in accordance with the service bulletin described previously.
An owner/operator (pilot), holding at least a private pilot certificate, may perform the visual checks required by paragraph (b) of this AD and must enter compliance into the aircraft maintenance records in accordance with 14 CFR sections 43.11 and 91.417(a)(2)(v)). A pilot may perform this check because it is a visual check for a gap or movement of the bolt and can be performed equally well by a pilot or a mechanic.
The short compliance time involved is required because the previously described critical unsafe condition can adversely affect the controllability or structural integrity of the helicopter. Therefore, removing, inspecting, and reinstalling each bolt at the specified time intervals, and replacing any unairworthy bolt with an airworthy bolt is required before further flight and this AD must be issued immediately.
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 letters issued on July 2, 2003, to all known U.S. owners and operators of MDHI Model MD900 helicopters. These conditions still exist, and the AD is hereby published in the Federal Register as an amendment to 14 CFR 39.13 to make it effective to all persons.
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 AD system. The regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance. Because we have now included this material in part 39, we no longer need to include it in each individual AD.
The FAA estimates that this AD will affect 32 helicopters of U.S. registry, and the inspections and replacement of a bolt will take approximately 13 work hours per helicopter to accomplish at an average labor rate of $65 per work hour. Required parts will cost approximately $800 per bolt (2 bolts per blade and 5 blades) per helicopter. Based on these figures, we estimate the total cost impact of the AD on U.S. operators to be $283,040, assuming all bolts are replaced.
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 should 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 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 mailed comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket No. 2003-SW-33-AD." The postcard will be date stamped and returned to the commenter.
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 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 a new airworthiness directive to read as follows: