This amendment adopts a new AD for Sikorsky Model S92-A helicopters. This action requires, within a specified time, borescope inspecting a certain part-numbered shaft and bearing assembly and also inspecting after any installation. This amendment is prompted by an incident involving failure of a shaft and bearing assembly and servo clevis shaft resulting in loss of tail rotor control. This condition, if not detected, could result in loss of tail rotor pitch and yaw control and subsequent loss of control of a helicopter.
We have reviewed Sikorsky Alert Service Bulletin No. 92-64-002, dated August 3, 2007 (ASB), which describes procedures for doing a one- time borescope inspection of the shaft and bearing assembly.
The ASB requires inspecting the shaft and bearing assembly within 50 hours time-in-service (TIS). This AD requires the inspection within 20 hours TIS based on the ease of the inspection, the availability of borescopes, the flight hours perday for the high time helicopters (about 8 hours), and the potential for a helicopter to ditch while servicing the oil rig industry. Also, this AD requires this inspection between 10 and 15 hours TIS following any installation of a shaft and bearing assembly.
The inspections required by this AD are interim actions; the manufacturer continues to investigate failure of the shaft and bearing assembly and we may either develop follow-on actions or a terminating action for the requirements of this AD.
This unsafe condition is likely to exist or develop on other helicopters of the same type design. Therefore, this AD is being issued to prevent failure of a shaft and bearing assembly, loss of tail rotor pitch and yaw control, and subsequent loss of control of a helicopter. This AD requires, within 20 hours TIS, inspecting each affected shaft and bearing assembly at the tail rotor side and on the servo side through the oil filler cap. This AD also requires borescope inspecting each shaft and bearing assembly that is installed as a replacement. This inspection must be done between 10 and 15 hours TIS after installation. Replacing any unairworthy shaft and bearing assembly is required before further flight.
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, borescope inspecting the affected shaft and bearing assembly within 20 hours TIS and before further flight following any installation of an affected shaft and bearing assembly are required, and this AD must be issued immediately.
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.
We estimate that this AD will affect 34 helicopters, and the borescope inspection of the shaft and bearing assembly will take about 2 work hours to do at an average labor rate of $80 per work hour. Required parts will cost about $30,864 per helicopter. Based on these figures, we estimate the total cost impact of the AD on U.S. operators to be $1,054,816.
Comments Invited
This AD is a final rule that involves requirements that affect flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any written data, views, or arguments regarding this AD. Send your comments to an address listed under ADDRESSES. Include "Docket No. FAA-2007-28971; Directorate Identifier 2007-SW-32-AD'' at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the AD. We will consider all comments received by the closing date and may amend the AD in light of those comments.
We will post all comments we receive, without change, to http://dms.dot.gov , including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this AD. Using the search function of our docket web site, you can find and read the comments to any of our dockets, including the name of the individual who sent the comment. You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov .
Regulatory Findings
We have determined that this AD will not have federalism implications under Executive Order 13132. This AD 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.
For the reasons discussed above, I certify that the regulation:
1. Is not a "significant regulatory action'' under ExecutiveOrder 12866;
2. Is not a "significant rule'' under the 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.
We prepared an economic evaluation of the estimated costs to comply with this AD. See the DMS to examine the economic evaluation.
Authority for This Rulemaking
Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.
We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, "General requirements.'' Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.
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.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive to read as follows: