Discussion
The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union, has issued EASA AD No. 2010-0189, dated September 23, 2010, to correct an unsafe condition for the Agusta Model AB139 and AW139 helicopters. EASA advises of some in-flight emergencies resulting from internal corrosion of the MAU2 circuit card assemblies. Analysis of the in-flight emergencies identified salt water and extreme moisture as contributory factors. The corrosion resulted from the MAU2 being exposed to external moisture as a result of the ventilation duct installation that routes external air directly on the MAU2 modules. When exposed to high levels of moisture, EASA states the MAU can cause the system to provide false indications or misleading data to be displayed to the flight crew. Also, misleading data may cause disengagement of the flight director modes of the autopilot or other alerting system anomalies. They also state that these failures and anomalies would significantly increase the workload of the flight crew and could ultimately lead to loss of control of the helicopter.
Related Service Information
Agusta has issued Bollettino Tecnico No. 139-166, dated April 6, 2009 (BT), which specifies inspecting the MAU2 cards to ensure they are corrosion free. Also, the BT specifies procedures for modifying to reroute the direct flow of air coming from the ventilation duct outlet MAU2 ventilation away from the MAU2 cabinet and modules. EASA classified this service information as mandatory and issued AD No. 2010-0189, dated September 23, 2010, to ensure the continued airworthiness of these helicopters.
FAA's Evaluation and Unsafe Condition Determination
These helicopters have been approved by the aviation authority of Italy and are approved for operation in the United States. Pursuant to our bilateral agreement with Italy, EASA, their technical representative, has notifiedus of the unsafe condition described in the EASA AD. We are issuing this AD because we evaluated all information provided by EASA and determined the unsafe condition exists and is likely to exist or develop on other helicopters of these same type designs.
Differences Between This AD and the EASA AD
We do not require reporting inspection results nor coordinating with the manufacturer in returning modules as indicated in the BT that EASA
[[Page 68298]]
references. Also, we have used a different compliance time for the action.
FAA's Determination and 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 detect corrosion of certain modules, to prevent the display of misleading data, disengagement of the flight director modes of the autopilot or other alert system anomalies, increased workload of the flight crew, and subsequent loss of control of the helicopter. This AD requires, at a specified interval, inspecting certain modules and related connectors for corrosion. If there is corrosion on the connectors, this AD requires cleaning the connectors before further flight. If there is corrosion on a module, this AD requires replacing the module with an airworthy module. This AD also requires modifying the MAU2 ventilation duct.
The short compliance time involved is required because the previously described critical unsafe condition can adversely affect the controllability of the helicopter. Therefore, inspecting, replacing, or modifying certain modules is required within a very short compliance time, 30 hours time-in-service or 1 month, whichever occurs first, so 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 inless than 30 days.
Costs of Compliance
We estimate that this AD will affect about 26 helicopters of U.S. registry. We also estimate that it will take 6 work hours to remove, inspect the modules for corrosion, and replace the corroded modules, and 2 work hours to reroute the ventilation tube. The average labor rate is $85 per work-hour. Required parts will cost about $360,738 per helicopter to replace corroded modules and $440 for parts to modify the ventilation tube. Based on these figures, we estimate the cost of this AD on U.S. operators is $361,858 per helicopter or $9,408,308 for the U.S. fleet, assuming the modules would be replaced on the entire fleet.
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-2011-1036; Directorate Identifier 2010-SW-088-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://www.regulations.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 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 theFAA 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.