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Federal Register / Vol. 86, No. 47 / Friday, March 12, 2021 / Proposed Rules
Actions Since AD 20140406 Was Issued Since the FAA issued AD 201404
06, the manufacturer has published new service information that revises the inspections for certain HMUs, reduces compliance times for initial inspections, and allows application of noncumulative tolerance of 10% of operating hours to be applied to the timing of the repetitive inspection of HMUs installed on certain engines.
The European Union Aviation Safety Agency EASA, which is the Technical Agent for the Member States of the European Community, has issued EASA
AD 20200033, dated February 25, 2020
referred to after this as the MCAI, to address the unsafe condition on these products. The MCAI states:
A number of in-flight shutdown IFSD
occurrences have been reported for ARRIUS
2 engines. The results of the technical investigations concluded that these events were caused by deterioration of the splines on the high pressure HP/low pressure LP
pump assembly drive shaft of the HMU, which eventually interrupted the fuel supply to the engine.
This condition, if not detected and corrected, could lead to further cases of engine IFSD, possibly resulting in forced landing with consequent damage to the helicopter and injury to occupants. To address these occurrences, Turbomeca published MSB 319 73 2825 up to version G to provide instructions for inspection of the HMU and sleeve assembly. Consequently, EASA issued AD 20130082 to require repetitive inspections of the drive gear shaft splines of the HP pump, and, depending on findings, accomplishment of applicable corrective actions.
Since that EASA AD was issued, SAFRAN published the MSB to provide
specific inspection instructions for HMU
installed on a helicopter after 31 January 2013, to reduce the compliance time for the initial inspection of Group 1 engines that were not previously inspected in accordance with version G or later of the MSB, and to provide some operational margin before the first inspection in all possible scenarios.
For the reason described above, this EASA AD retains the requirements of AD
20130082, which is superseded, and requires accomplishment of the actions in accordance with the instructions of the MSB, as defined in this EASA AD.

You may obtain further information by examining the MCAI in the AD
docket at https www.regulations.gov by searching for and locating Docket No.
FAA20210137.
FAAs Determination This product has been approved by EASA and is approved for operation in the United States. Pursuant to the FAAs bilateral agreement with the European Community, EASA has notified the agency of the unsafe condition described in the MCAI and service information. The FAA is issuing this NPRM because the agency evaluated all the relevant information provided by EASA and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design.
Related Service Information Under 1
CFR Part 51
The FAA reviewed Safran Helicopter Engines Mandatory Service Bulletin MSB No. 319 73 2825, Version J, dated March 15, 2019. The MSB describes procedures for inspecting the HMU high pressure pump drive gear shaft splines and cleaning and inspecting the sleeve
assembly splines. This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in ADDRESSES.
Proposed AD Requirements in This NPRM
This proposed AD would retain certain requirements of AD 20140406.
This proposed AD would require initial and repetitive inspections of the HMU
high pressure pump drive gear shaft splines. This proposed AD would require cleaning of the sleeve assembly splines. This proposed AD would also require replacing the HMU or the sleeve assembly on the affected high pressure pump drive gear shaft if the HMU fails inspection.
Differences Between This Proposed AD
and the Service Information or the MCAI
EASA AD 20200033 identifies applicable engines as Safran Helicopter Engines Arrius 2B1, 2B1A, 2B2, 2G1, 2K1 and 2K2 model turboshaft engines, all serial numbers. This AD does not include Safran Helicopter Engines Arrius 2G1 and 2K2 model turboshaft engines in its applicability since these engines are not type certificated in the United States.
Costs of Compliance The FAA estimates that this AD, if adopted as proposed, would affect 194
engines installed on helicopters of U.S.
registry.
The FAA estimates the following costs to comply with this proposed AD:

ESTIMATED COSTS
Parts cost
Action
Labor cost
Visual inspection of drive gear shaft splines;
cleaning and inspection of sleeve assembly splines.

2 work-hours $85 per hour = $170

The FAA estimates the following costs to do any necessary replacements that would be required based on the
results of the proposed inspection. The agency has no way of determining the
Cost per product
$900

$1,070

Cost on U.S.
operators $207,580

number of aircraft that might need these replacements.

ON-CONDITION COSTS
Parts cost
Cost per product
Action
Labor cost
Replace sleeve assembly on high-pressure pump drive gear shaft.
Replace HMU

1 work-hour $85 per hour = $85

$898

$983

1 work-hour $85 per hour = $85

45,000

45,085

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