Federal Register - February 25, 2021
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Source: Federal Register
11474
Federal Register / Vol. 86, No. 36 / Thursday, February 25, 2021 / Proposed Rules
crack initiated and grew under service loading until the Hamilton Sundstrand 54H60 model propeller blade could no longer sustain the applied loads and ultimately the blade separated. The separation of the blade resulted in the loss of the airplane and 17 fatalities. The investigation further revealed that 54H60 model propeller blades manufactured before 1971 are susceptible to cracks of the propeller blade in the area of the internal taper bore. The applicability of AD 202012
07 was therefore limited to those Hamilton Sundstrand 54H60 model propellers blades with a blade serial number S/N below 813320, which are those propeller blades manufactured before 1971. AD 20201207 required initial and repetitive ECI of the affected propeller blades and replacement of any propeller blade that fails inspection.
The agency issued AD 20201207 to detect cracking in the propeller blade taper bore.
Hamilton Sundstrand Alert Service Bulletin ASB 54H6061A154, Revision 1, dated May 29, 2020, to expand the effectivity of the ASB to include all propeller blades installed on a propeller that contains a blade S/N
below 813320, and all propeller blades installed on a propeller that has not been overhauled within ten years.
Hamilton Sundstrand ASB 54H6061
A154, Revision 1, dated May 29, 2020, also provides instructions for concurrent compliance with Hamilton Sundstrand ASB 54H6061A155, dated May 29, 2020, to ECI an expanded and deeper taper bore area.
Actions Since AD 20201207 Was Issued Since the FAA issued AD 202012
07, the manufacturer determined that all propeller blades installed on Hamilton Sundstrand 54H model propellers with a 54H60 model propeller hub are susceptible to intergranular corrosion cracking in the blade taper bore. As a result, the manufacturer published
The FAA reviewed Hamilton Sundstrand ASB 54H6061A154, Revision 1, dated May 29, 2020. This ASB identifies the affected propeller models and specifies procedures for performing an ECI of the propeller blade taper bore. The FAA also reviewed Hamilton Sundstrand ASB 54H6061
A155, dated May 29, 2020. This ASB
also identifies affected propeller models
FAAs Determination The FAA is issuing this NPRM after determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design.
Related Service Information Under 1
CFR Part 51
and specifies procedures for performing an expanded ECI of the propeller blade taper bore. 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 20201207.
This proposed AD would require initial and repetitive ECI of all propeller blades installed on Hamilton Sundstrand 54H60 propeller hubs and replacement of any propeller blade that fails inspection.
Interim Action The FAA considers that this proposed AD would be an interim action. This unsafe condition is still under investigation by the manufacturer and, depending on the results of that investigation, the FAA may consider further rulemaking action.
Costs of Compliance The FAA estimates that this AD, if adopted as proposed, would affect 212
propellers installed on 53 aircraft of U.S. registry.
The FAA estimates the following costs to comply with this proposed AD:
ESTIMATED COSTS
Action
Labor cost
ECI all propeller blades installed on propeller Report results of ECI
16 work-hours $85 per hour = $1,360
1 work-hour $85 per hour = $85
The FAA estimates the following costs to do any necessary replacement that would be required based on the
Parts cost
results of the proposed inspection. The agency has no way of determining the
$700
0
Cost per product $2,060
85
Cost on U.S.
operators $436,720
18,020
number of aircraft that might need this replacement:
ON-CONDITION COSTS
Action
Labor cost
Replace propeller blade
1 work-hour $85 per hour = $85
Paperwork Reduction Act A federal agency may not conduct or sponsor, and a person is not required to respond to, nor shall a person be subject to a penalty for failure to comply with a collection of information subject to the requirements of the Paperwork Reduction Act unless that collection of information displays a currently valid OMB Control Number. The OMB
Control Number for this information
VerDate Sep<11>2014
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collection is 21200056. Public reporting for this collection of information is estimated to be approximately 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, completing and reviewing the collection of information. All responses to this collection of information are mandatory. Send
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Parts cost $63,500
Cost per product $63,585
comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to:
Information Collection Clearance Officer, Federal Aviation Administration, 10101 Hillwood Parkway, Fort Worth, TX 761771524.
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