[Federal Register Volume 85, Number 115 (Monday, June 15, 2020)]
[Rules and Regulations]
[Pages 36145-36148]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-12821]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-1008; Project Identifier AD-2019-00110-P; 
Amendment 39-21142; AD 2020-12-07]
RIN 2120-AA64


Airworthiness Directives; Hamilton Sundstrand Corporation 
Propellers

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain Hamilton Sundstrand Corporation (Hamilton Sundstrand) 54H60 
model propellers. This AD was prompted by the failure of a propeller 
blade that resulted in the loss of the airplane. This AD requires 
initial and repetitive eddy current inspections (ECIs) of the affected 
propeller blades and replacement of the propeller blades that fail the 
inspection. The FAA is issuing this AD to address the unsafe condition 
on these products.

DATES: This AD is effective July 20, 2020.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of July 20, 
2020.

ADDRESSES: For service information identified in this final rule, 
contact Hamilton Sundstrand, 1 Hamilton Road, Windsor Locks, CT 06096-
1010, United States; phone: (877) 808-7575; email: [email protected]. You 
may view this service information at the FAA, Airworthiness Products 
Section, Operational Safety Branch, 1200 District Avenue, Burlington, 
MA 01803. For information on the availability of this material at the 
FAA, call 781-238-7759. It is also available on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2019-
1008.

Examining the AD Docket

    You may examine the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2019-
1008; or in person at Docket Operations between 9 a.m. and 5 p.m., 
Monday

[[Page 36146]]

through Friday, except Federal holidays. The AD docket contains this 
final rule, any comments received, and other information. The address 
for Docket Operations is U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE, Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Maureen Maisttison, Aerospace 
Engineer, Boston ACO Branch, FAA, 1200 District Avenue, Burlington, MA 
01803; phone: 781-238-7076; fax: 781-238-7199; email: 
[email protected].

SUPPLEMENTARY INFORMATION:

Discussion

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to certain Hamilton 
Sundstrand 54H60 model propellers. The NPRM published in the Federal 
Register on January 28, 2020 (85 FR 4916). The NPRM was prompted by a 
report of the separation of a 54H60 model propeller blade installed on 
a United States Marine Corps Reserve (USMCR) KC-130T airplane during a 
flight in July 2017.
    The USMCR investigation of this event revealed the Hamilton 
Sundstrand 54H60 model propeller blade separated due to corrosion 
pitting and a resultant intergranular radial crack that was not 
corrected at the last propeller overhaul. From this intergranular 
crack, a fatigue 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 this AD is therefore limited to those Hamilton 
Sundstrand 54H60 model propellers blades with a blade serial number 
below 813320, which are those propeller blades manufactured before 
1971.
    The NPRM proposed to require initial and repetitive ECIs of the 
affected propeller blades and removal from service of any blades that 
fail these inspections. Propeller blade taper bore cracks, if not 
detected, could result in failure of the propeller blade, blade 
separation, and loss of the airplane. The FAA is issuing this AD to 
address the unsafe condition on these products.

Comments

    The FAA gave the public the opportunity to participate in 
developing this final rule. The FAA received one comment, from Lockheed 
Martin Aeronautics Company (LMAC). The following presents the FAA's 
response.

Comment on Cause of Propeller Blade Separation

    LMAC commented that the Discussion section of the NPRM indicated 
that the propeller blade separated from the KC-130T airplane as the 
result of corrosion that was not corrected at the last propeller 
overhaul. LMAC noted that the investigation completed by the U.S. Navy 
and the U.S. Air Force concluded that the separation was a result of a 
fatigue crack which grew under service loading until the blade could no 
longer sustain the applied loads.
    The FAA revised the Discussion section of this final rule to state 
that the investigation concluded that corrosion pitting and a resultant 
intergranular radial crack was not corrected at the last propeller 
overhaul. From this intergranular crack, a fatigue 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. No change to this AD is required.

Comment on Difference in Compliance Time

    LMAC commented that the compliance time in paragraphs (g)(1) and 
(2) of the NPRM differs from the time recommended by LMAC in its two 
applicable Alert Service Bulletins (ASBs): AV382-61-011, dated October 
3, 2019, for all ``382 models'' (excluding the 382J) and 88/SB-723, 
dated November 6, 2019, for L-188 Electra aircraft types. LMAC has 
recommended that its customers comply with the Hamilton Sundstrand ASB 
54H60-61-A154, dated August 26, 2019, within 90 days of receipt of the 
applicable aircraft-type LMAC ASB. LMAC stated that this 90-day 
compliance time was based on an aircraft-level risk assessment that 
considered the consequence of loss of the propeller and the probability 
of occurrence based on the reported cases of intergranular cracking of 
the blade.
    The FAA applied Advisory Circular (AC) 39-8, ``Continued 
Airworthiness Assessments of Powerplant and Auxiliary Power Unit 
Installations of Transport Category Airplanes,'' dated September 8, 
2003 (``AC 39-8'') to identify the unsafe condition and to assess the 
risk for propellers installed in transport aircraft. The FAA's risk 
assessment for the Hamilton Sundstrand 54H60 propeller affected by this 
AD did not support the compliance interval proposed by LMAC in its 
ASBs. The FAA's risk assessment did not justify mandating that all 
blades be inspected within 90 days, per the LMAC recommendation. No 
change to this AD is required.

Comment on Relationship Between Unsafe Condition, Overhaul Period, and 
Blade Cracking

    LMAC commented that the severity of this ``hazard/unsafe 
condition'' is not influenced by the overhaul period and there is no 
known correlation between time since overhaul and probability of 
intergranular cracking.
    The FAA agrees that the severity of this unsafe condition is not 
influenced by the overhaul period and there is no known correlation 
between time since overhaul and probability of intergranular cracking. 
There is little established knowledge of this type of intergranular 
crack initiation and growth in this aluminum alloy, although an 
investigation has been underway for 2 years. However, the FAA has 
determined that since corrosion occurs regardless of whether the 
propeller is in service and corrosion has been discovered in blades 
exhibiting intergranular cracks, the appropriate compliance time uses 
calendar time after the effective date of this AD, based on the time of 
the last overhaul.
    This AD employs risk-based inspections by placing priority on 
inspecting blades that have higher calendar time since their last 
overhaul because these blades have a higher probability of corrosion. 
In most cases, corrosion has been found to exist in conjunction with 
intergranular cracking. Moreover, this AD imposes a mandatory reporting 
requirement for cracked blades and the FAA expects that such blades 
will be subject to additional metallurgical examinations intended to 
identify factors influencing intergranular cracking. The FAA may 
consider further rulemaking action on this unsafe condition, depending 
on the results of these examinations. No change to this AD is required.

Conclusion

    The FAA reviewed the relevant data, considered the comments 
received, and determined that air safety and the public interest 
require adopting this final rule as proposed except for minor editorial 
changes. These minor changes:
     Are consistent with the intent that was proposed in the 
NPRM for addressing the unsafe condition; and

[[Page 36147]]

     Do not add any additional burden upon the public than was 
already proposed in the NPRM.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Hamilton Sundstrand Corporation ASB 54H60-61-A154, 
dated August 26, 2019. The ASB describes procedures for performing an 
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 
the ADDRESSES section.

Interim Action

    The FAA considers this AD interim action. The root cause of the 
54H60 model propeller blade separation is still under investigation. 
The FAA may consider further rulemaking action.

Costs of Compliance

    The FAA estimates that this AD affects 212 propellers installed on 
53 aircraft of U.S. registry.
    The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
               Action                         Labor cost            Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
ECI of propeller...................  8 work-hours x $85 per hour            $700          $1,380        $292,560
                                      = $680.
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    The FAA estimates the following costs to do any necessary 
replacements that would be required based on the results of the 
inspection. The FAA has no way of determining the number of aircraft 
that might need these replacements:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                   Action                                 Labor cost                Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replace blade..............................  1 work-hour x $85 per hour = $85...         $63,500         $63,585
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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 collection is 2120-0056. 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 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 
76177-1524.

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.
    The FAA is 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

    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) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Will not affect intrastate aviation in Alaska, 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.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13   [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive (AD):

2020-12-07 Hamilton Sundstrand Corporation: Amendment 39-21142; 
Docket No. FAA-2019-1008; Project Identifier AD-2019-00110-P.

(a) Effective Date

    This AD is effective July 20, 2020.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all Hamilton Sundstrand Corporation (Hamilton

[[Page 36148]]

Sundstrand) model 54H60 propellers with a blade having a serial 
number (S/N) below S/N 813320.

(d) Subject

    Joint Aircraft System Component (JASC) Code 6111, Propeller 
Blade Section.

(e) Unsafe Condition

    This AD was prompted by the separation of a propeller blade that 
resulted in the loss of an airplane and 17 fatalities. The FAA is 
issuing this AD to detect cracking in the propeller blade taper 
bore. The unsafe condition, if not addressed, could result in 
failure of the propeller blade, blade separation, and loss of the 
airplane.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Required Actions

    (1) For affected propellers identified in Planning Information, 
paragraph 1.E.(1), of Hamilton Sundstrand Corporation Alert Service 
Bulletin (ASB) 54H60-61-A154, dated August 26, 2019 (``the ASB''), 
perform an eddy current inspection (ECI) of all blades installed on 
the propeller within one year or 500 flight hours after the 
effective date of this AD, whichever occurs first.
    (2) For affected propellers identified in Planning Information, 
paragraph 1.E.(2), of the ASB, perform an ECI of all blades 
installed on the propeller within two years or 1,000 flight hours 
after the effective date of this AD, whichever occurs first.
    (3) Perform the ECI of the affected propeller blades using the 
Accomplishment Instructions, paragraph 3.C. of the ASB.
    (4) If any propeller blade fails any inspection required by this 
AD, based on the criteria in paragraph 3.C. of the ASB, remove the 
blade from service and replace with a blade eligible for 
installation prior to the next flight.
    (5) For all affected propellers, repeat the inspection required 
by paragraphs (g)(1) through (4) of this AD at intervals not 
exceeding 3 years or 1,500 flight hours, whichever comes first, 
after the previous inspection.
    (6) Report the results of the ECI required by paragraphs (g)(1) 
through (5) of this AD in accordance with the Accomplishment 
Instructions, paragraph 3.C.(6) of the ASB.

(h) Installation Prohibition

    After the effective date of this AD, do not install any Hamilton 
Sundstrand propeller blades having an S/N below 813320 on any 
propeller, unless the blade has first passed the inspection required 
by this AD. After the effective date of this AD, do not install any 
propeller assemblies with affected propeller blades onto any 
aircraft unless the affected propeller blades have passed the 
inspection required by paragraph (g) of this AD.

(i) Paperwork Reduction Act Burden Statement

    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 collection is 
2120-0056. 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 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 76177-1524.

(j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Boston ACO Branch, FAA, has the authority to 
approve AMOCs for this AD, if requested using the procedures found 
in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request 
to your principal inspector or local Flight Standards District 
Office, as appropriate. If sending information directly to the 
manager of the certification office, send it to the attention of the 
person identified in paragraph (k) of this AD.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.

(k) Related Information

    For more information about this AD, contact Maureen Maisttison, 
Aerospace Engineer, Boston ACO Branch, FAA, 1200 District Avenue, 
Burlington, MA 01803; phone: 781-238-7076; fax: 781-238-7199; email: 
[email protected].

(l) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Hamilton Sundstrand Corporation (Hamilton Sundstrand) Alert 
Service Bulletin 54H60-61-A154, dated August 26, 2019.
    (ii) [Reserved]
    (3) For Hamilton Sundstrand service information identified in 
this AD, contact Hamilton Sundstrand, 1 Hamilton Road, Windsor 
Locks, CT 06096-1010, United States; phone: (877) 808-7575; email: 
[email protected].
    (4) You may view this service information at the FAA, 
Airworthiness Products Section, Operational Safety Branch, 1200 
District Avenue, Burlington, MA 01803. For information on the 
availability of this material at the FAA, call 781-238-7759.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, email: [email protected], or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on June 3, 2020.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2020-12821 Filed 6-12-20; 8:45 am]
 BILLING CODE 4910-13-P