Comments Invited
This AD is a final rule that involves requirements affecting flight safety, and we did not provide you with notice and an opportunity to provide your comments prior to it becoming effective. However, we invite you to participate in this rulemaking by submitting written comments, data, or views. We also invite comments relating to the economic, environmental, energy, or federalism impacts that resulted from adopting this AD. The most helpful comments reference a specific portion of the AD, explain the reason for any recommended change, and include supporting data. To ensure the docket does not contain duplicate comments, commenters should send only one copy of written comments, or if comments are filed electronically, commenters should submit them only one time. We will file in the docket all comments that we receive, as well as a report summarizing each substantive public contact with FAA personnel concerning this rulemaking duringthe comment period. We will consider all the comments we receive and may conduct additional rulemaking based on those comments.
Discussion
On October 28, 2015 we issued Emergency AD 2015-22-52 for Airbus Helicopters Model AS350B3 helicopters with a dual hydraulic system that prohibited performing the yaw load compensator check (collective switch) during preflight procedures and instead required performing it during post-flight procedures. Emergency AD 2015-22-52 also required the yaw servo hydraulic switch (collective switch) to be in the ``ON'' (forward) position before taking off. Emergency AD 2015-22-52 was sent previously to all known U.S. owners and operators of these helicopters. The actions in Emergency AD 2015-22-52 were intended to prevent takeoff without hydraulic pressure in the T/R hydraulic system, loss of T/R flight control, and subsequent loss of control of the helicopter.
Emergency AD 2015-22-52 was prompted by two accidents and one incident of Airbus Helicopters Model AS350B3 helicopters with a dual hydraulic system installed. From preliminary investigations, loss of T/ R control during takeoff was evident in each event. Each event experienced a counterclockwise rotational yaw immediately after takeoff. It was also noted that the anti-torque pedals felt jammed or locked in the neutral position by the pilots in the two non-fatal events. The conditions in the events are indicative of takeoffs without hydraulic T/R assistance caused by a lack of pressure in the T/R hydraulic system. When taking off without T/R hydraulic assistance with the switch on the collective grip in the ``OFF'' (aft) position, the yaw load compensator remains discharged and degrades the T/R hydraulic system, which significantly increases the pilot T/R control load and prevents sufficient T/R thrust for takeoff.
Based on the accidents and incident, EASA, which is the Technical Agent for the Member States of the European Union, issued EASA AD No. 2015-0178, datedAugust 26, 2015, to correct an unsafe condition for Airbus Helicopters Model AS 350 B3 helicopters, equipped with a dual hydraulic system identified as modification OP 3082 or OP 3346. EASA advises of a perceived loss of T/R control that mimics jamming during take-off if the T/R hydraulic preflight checks are not performed in accordance with the checklist in the RFM. According to EASA, performing the T/R hydraulic preflight checks improperly may result in reduced function of the T/R hydraulic system, thereby significantly increasing the T/R control load for the pilot.
After we issued Emergency AD 2015-22-52, we received comments noting an error in terminology and a defect in reporting compliance that resulted in confusion in how to comply with Emergency AD 2015-22- 52. Specifically, we referred to the collective switch for the yaw load compensator check, when we should have referred to the ACCU TST switch. Activating the collective switch after rotor shut-down will have no effect due to the absence of hydraulic pressure in the system. We also omitted a method of recording compliance. Therefore, on October 30, 2015, we issued Emergency AD 2015-22-53 to supersede Emergency AD 2015- 22-52 to correct the error in terminology and the defect in recording compliance. Emergency AD 2015-22-53 requires revising the normal operating procedures section of the RFM to prohibit performing the yaw load compensator check (ACCU TST switch) during preflight procedures and instead require performing it during post-flight procedures after rotor shut-down. Emergency AD 2015-22-53 also requires revising the RFM to state that
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the yaw servo hydraulic switch (collective switch) must be in the ``ON'' (forward) position before taking off. Emergency AD 2015-22-53 was also sent previously to all known U.S. owners and operators of these helicopters.
FAA's Determination
This helicopter has been approved by the aviation authority of France and is approved for operation in the United States. Pursuant to our bilateral agreement with France, EASA, its technical representative, has notified us 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 this same type design.
Related Service Information
Airbus Helicopters issued Service Bulletin No. AS350-67.00.66, Revision 1, dated October 22, 2015 (SB AS350-67.00.66), which specifies inserting specific pages of the bulletin into the RFM. These pages revise the preflight and post-flight hydraulic checks by moving the T/R yaw load compensator check from preflight to post-flight. These pages also revise terminology within the flight manuals for the different engine configurations.
Airbus Helicopters also issued Safety Information Notice No. 2944- S-29, Revision 0, dated August 26, 2015 (SIN 2944-S-29), which warns thatattempting to take off without T/R hydraulic assistance (which may be caused by the yaw servo hydraulic switch on the collective grip in the ``OFF'' (aft) position) might be incorrectly perceived as T/R control failure (jam), which could lead to loss of control of the helicopter if not quickly identified and corrected. SIN 2944-S-29 also advises of the RFM update that revises the run-up hydraulic check starting procedures to no longer specify ``pressing'' the yaw servo hydraulic switch. To mitigate this potential error, the yaw load compensator check has been moved from preflight to post-flight procedures. Further, SIN 2944-S-29 states the yaw servo hydraulic switch, which is located on the collective grip, is also called the hydraulic pressure switch or hydraulic cut off switch in various RFMs.
AD Requirements
This AD requires, before further flight, revising the RFM to stop performing the yaw load compensator check (ACCU TST switch) during preflight procedures and insteadperform the yaw load compensator check during post-flight procedures after rotor shut-down. This AD also requires revising the RFM to state that the yaw servo hydraulic switch (collective switch) must be in the ``ON'' (forward) position before taking off.
Differences Between This AD and the EASA AD
The EASA AD requires revising the RFM by incorporating procedures contained in Airbus Helicopters Service Bulletin No. AS350-67.00.66, Revision 0, dated August 26, 2015, and informing all flight crew of the RFM changes. This AD requires revising the RFM by inserting a copy of this AD or by making pen and ink changes.
Interim Action
We consider this AD to be an interim action. The design approval holder is currently developing a terminating action that will address the unsafe condition identified in this AD. Once this terminating action is developed, approved, and available, we might consider additional rulemaking.
Costs of Compliance
We estimate that this ADaffects 427 helicopters of U.S. Registry. We estimate that operators may incur the following costs in order to comply with this AD at an average labor rate of $85 per work-hour. It takes about 0.5 work-hour to revise an RFM for a cost of $43 per helicopter and $18,361 for the U.S. fleet.
FAA's Justification and Determination of the Effective Date
Providing an opportunity for public comments prior to adopting these AD requirements would delay implementing the safety actions needed to correct this known unsafe condition. Therefore, we found and continue to find that the risk to the flying public justifies waiving notice and comment prior to the adoption of this rule because the previously described unsafe condition can adversely affect the controllability of the helicopter and the initial required action must be accomplished before further flight.
Since it was found that immediate corrective action was required, notice and opportunity for prior public comment before issuingthis AD were impracticable and contrary to public interest and good cause existed to make the AD effective immediately by Emergency AD 2015-22- 53, issued on October 30, 2015, to all known U.S. owners and operators of these helicopters. These conditions still exist and the AD is hereby published in the Federal Register as an amendment to section 39.13 of the Federal Aviation Regulations (14 CFR 39.13) to make it effective to all persons.
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.
Regulatory Findings
We 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, I certify that this AD:
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);
3. Will not affect intrastate aviation in Alaska to the extent that it justifies making a regulatory distinction; and
4. 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 and placed it in the AD docket.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.