Discussion
On April 4, 2012, at 77 FR 20321, the Federal Register published our notice of proposed rulemaking (NPRM), which proposed to amend 14 CFR part 39 to include an AD that would apply to ECD Model MBB-BK 117 A-3, MBB-BK 117 A-4, MBB-BK B-1, MBB-BK 117 B-2, and MBB-BK C-1 helicopters equipped with a certain hoist system. That NPRM proposed to require deactivating the entire hoist system or deactivating the hoist system cable cutter function on the operator handle. The proposed requirements were intended to prevent uncommanded cutting of the hoist cable and subsequent injury to persons being lifted by the hoist.
The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union, has issued EASA AD No. 2011-0126, dated July 1, 2011 (EASA AD 2011-0126), to correct an unsafe condition for the ECD Model MBB-BK 117 A-3, MBB-BK 117 A-4, MBB- BK B-1, MBB-BK 117 B-2, and MBB-BK C-1 helicopters equipped with a certain hoist system. EASA AD 2011-0126 requires deactivation of the affected external hoist system by pulling and securing the related circuit breakers, or by removing the hoist boom.
After EASA AD 2011-0126 was issued, it was discovered that pulling the circuit breaker WARN ANN II degraded the annunciator system's redundant power supply, so that pilots could not be warned of a second helicopter system failure. Prompted by these findings, EASA issued superseding EASA AD No. 2011-0131, dated July 8, 2011 (EASA AD 2011- 0131), to require pulling only three circuit breakers (CABLE CUTTER, WINCH CONT, and WINCH BOOM), while circuit breaker WARN ANN II remains inserted.
EASA advises that since EASA AD 2011-0131 was issued ``a corrective action has been developed to establish an adequate safety level, while a terminating action is under
[[Page 44117]]
investigation but currently not available.'' EASA subsequently issued the current EASA AD No. 2011-0148, dated August 5, 2011 (EASA AD 2011- 0148), which retains the requirements of EASA AD 2011-0131 and requires modification of the helicopter wiring and operator handle, part number (P/N) 76803, a revision to the Rotorcraft Flight Manual and Supplement, and repetitive inspections of the operator handle. EASA AD 2011-0148 also requires implementing a 10-year time frame for overhaul of the operator handle.
Comments
We gave the public the opportunity to participate in developing this AD, but we did not receive any comments on the NPRM.
FAA's Determination
These helicopters have been approved by the aviation authority of Germany and are approved for operation in the United States. Pursuant to our bilateral agreement with Germany, 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 developon other helicopters of these same type designs and that air safety and the public interest require adopting the AD requirements as proposed.
Interim Action
We consider this AD to be an interim action. The design approval holder is currently developing a terminating action to address the unsafe condition identified in this AD. Once this terminating action is developed, approved, and available, we might consider additional rulemaking.
Differences Between This AD and the EASA AD
This AD applies to the ECD Model MBB-BK 117 A-4 model. The EASA AD makes no mention of this model. The EASA AD also applies to the MBB-BK 117 A-1 model. Eurocopter informs us that the MBB-BK 117 A-1 model no longer exists, so we did not include it in our AD. The EASA AD requires temporary revisions to the Rotorcraft Flight Manual and its supplements; this AD does not. The EASA AD requires overhaul of the operator handle every ten years; this AD does not.
Related Service InformationECD has issued Emergency Alert Service Bulletin MBB-BK117-80-166, Revision 1, dated August 4, 2011 (ASB). The ASB specifies the deactivation of the cable cutter function on the operator handle. After the cable cutter function on the operator handle has been deactivated, the rescue winch may be used.
Costs of Compliance
We estimate that this AD will affect about 12 helicopters of U.S. registry.
We estimate the following costs to comply with this AD:
Option 1: Pull and secure three circuit breakers. We estimate that this task will require about one half-hour to complete. At $85 per work-hour, the labor cost will total about $43. No parts will be needed, so we estimate the total cost per helicopter to be $43, or $516 for the fleet.
Option 2: Remove the hoist boom from the helicopter. We estimate that this task will require 1.5 hours to complete at $85 per work-hour for a total labor cost of about $128. No parts will be needed, so we estimate the total cost per helicopter to be $128, or $1,536 for the fleet.
Option 3: We estimate that modifying the hoist operator handle will require four work-hours at $85 per work-hour for a total labor cost of $340 per helicopter. Parts will cost about $92. Inspecting the hoist-operator handle for damage will take about one half-hour for a labor cost of about $43. For 12 monthly inspections per year, the annual cost will total $516. We estimate that replacing the operator handle with a new operator handle will require 0.25 work hour at $85 an hour for a labor cost of about $21 per helicopter. Parts will cost about $18,500 for a total cost of $18,521 per helicopter. Total costs per helicopter will vary, depending on whether repairs are needed.
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 detailthe 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 helicopters identified in this rulemaking action.
Regulatory Findings
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 this AD:
(1) Isnot 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.