On December 18, 2009, we issued AD 2009-23- 51, Amendment 39-16190 (75 FR 5684, February 4, 2010), to require cleaning and inspecting each MGB assembly mounting foot pad and rib for a crack and corrosion. If you do not find a crack, the AD requires applying a corrosion preventive compound. If you find a crack, the AD requires replacing the MGB before further flight. If you find corrosion, bubbled paint, or paint discoloration, the AD requires you to repair the MGB before further flight. That action was prompted by reports of cracks in the MGB mounting foot pads and foot ribs. That condition, if not corrected, could result in loss of the MGB and subsequent loss of control of the helicopter.
Since issuing that AD, we have determined the need to expand the applicability to include another MGB assembly and MBG housing, which introduced a six-stud attachment for the oil filter bowl and more edge distance on the right and left foot pads. This new housing configuration is added to the applicability of this AD because it is prone to the same cracks as the MGB listed in the current AD. The manufacturer is still investigating the root cause of these cracks. Contributing factors may include corrosion and the bushing press fit in the mounting foot bolt hole. The actions specified in this AD are interim actions until the root cause of the cracking is determined. After that determination, we anticipate further rulemaking.
Since an unsafe condition has been identified that is likely to exist or develop on other Sikorsky S-92A helicopters of the same type design, this AD supersedes AD 2009-23-51 to retain the same requirements and to expand the applicability to include the MGB assembly, part number (P/N) 92351-15000-044, with a MGB housing, P/N 92351-15110-046. This AD is being issued to prevent the loss of the MGB and subsequent loss of control of the helicopter. This AD requires an initial and at 10-hour time-in-service (TIS) intervals, cleaning and inspecting each MGB assembly mounting foot pad and rib for a crack and corrosion. If you do not find a crack, this AD requires applying a corrosion preventive compound. If you find a crack, this AD requires replacing the MGB before further flight. If you find corrosion, bubbled paint, or paint discoloration, this AD requires you to repair the MGB before further flight.
The short compliance time is required because the previously described critical unsafe condition can adversely affect the structural integrity and controllability of the helicopter. Therefore, because of the short compliance time, 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 this AD will affect 44 helicopters of U.S. registry, and inspecting the MGB assembly mounting foot pads and foot ribs for corrosion or a crack will take about:
2 work hours to do the visual inspection, assuming 2200 (50 inspections X 44 helicopters) inspections per year for commercial and part 91 operators; and
24 work hours to remove and replace an MGB.
The average labor rate is $85 per work hour and required parts will cost about $590,000 per helicopter. Based on these figures, we estimate the total cost impact of the AD on U.S. operators to be $26,423,760 assuming all 44 helicopters will require an MGB replacement.
Comments Invited
This AD is a final rule that involves requirements affecting flight safety, and we did not precede it by notice and an opportunity for public comment. We invite you to send any written relevant data, views, or arguments regarding this AD. Send your comments to an address listed under the ADDRESSES section. Include "Docket No. FAA-2010-1136; Directorate Identifier 2010-SW-069-AD'' at the beginning ofyour 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:// www.regulations.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive concerning this AD. Using the search function of the 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).
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 Executive Order 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 AD docket 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, under the authority delegated to me by the Administrator, the FAA amends 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. The FAA amends Sec. 39.13 by removing Airworthiness Directive (AD) 2009-23-51, Amendment 39-16190 (75 FR 5684, dated February 4, 2010), and by adding a new AD to read as follows: