A proposal to amend 14 CFR part 39 to include an AD for the specified helicopters was published in the Federal Register on September 10, 2002 (67 FR 57351). That action proposed inspecting the pitch control assembly for roughness or binding of the bearings by hand-rotating the housing and if the housing does not rotate freely, replacing each unairworthy pitch control assembly with an airworthy unit.
The FAA has reviewed RHC Service Bulletin SB-43A, Revision A, dated June 10, 2002 (SB), which describes procedures for inspecting the pitch control assembly for roughness or binding of the bearings by hand- rotating the housing. If the housing does not rotate freely, the SB specifies replacing each unairworthy pitch control assembly, part number (P/N) A031-1, with an airworthy unit in accordance with the maintenance manual.
Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.
One commenter, the manufacturer, requests a change to the summary information to indicate that bearing failures have been reported only on RHC Model R22 helicopters, and there are no reports of failed bearings on Model R44 helicopters. The FAA agrees and has changed the preamble information to indicate that the bearing failures have occurred on the RHC Model R22 helicopters only.
The same commenter requests a change to the summary and the discussion sections to revise the failure sequence to indicate that bearing failure could result in loss of tail rotor thrust requiring a power-off landing. The commenter states that in all three of the bearing failures, the failed bearing caused the pitch control linkage to fail and the tail rotor to go to flat pitch but none of the failures resulted in an accident. The commenter also states that there was no breakup of the tail rotor assembly, no tail rotor contact of the tailboom, and no loss of control resulting in an accident. The FAA agrees that the failed bearing has not resulted in breakup of the tail rotor assembly and contact with the tailboom, and the likelihood of such a breakup and contact with the tailboom may be remote. Therefore, we have removed the reference to the breakup of the tail rotor assembly and contact with the tailboom from the failure sequence. We do not agree that the failure sequence should state that bearing failure could result in loss of tail rotor thrust requiring a power-off landing. The loss of directional control associated with this type of failure could result in loss of control of the helicopter, and a successful power-off landing may not be possible. The term "loss of control of the helicopter", however, may be understood to mean an almost certain catastrophic event, such as loss of cyclic or pitch control. That is not our intent when we use the failure sequence in our AD's. That sequence states what could happen not necessarily what will happen. Our intent is to convey the sequence of events that we intend to prevent by issuing the AD to correct the unsafe condition. Therefore, we have changed the failure sequence to state that loss of "directional" control can result.
After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed with the changes described previously. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.
The FAA estimates that this AD will affect 440 helicopters of U.S. registry, that it will take approximately 2.3 work hours per helicopter to inspect and replace each pitch control assembly, and that the average labor rate is $60 per work hour. Required parts will cost approximately $1145 per helicopter. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $564,520,assuming the pitch control assembly is replaced on the entire fleet.
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.
For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under 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. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it 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 a new airworthiness directive to read as follows: