Document ID: FAA-2015-4007-0006
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: Various Model 234 and Model CH-47D Helicopters
Posted Date: 2018-08-13T04:00Z

[Federal Register Volume 83, Number 156 (Monday, August 13, 2018)]
[Rules and Regulations]
[Pages 39874-39877]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-17112]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2015-4007; Product Identifier 2015-SW-064-AD; Amendment 
39-19351; AD 2018-16-11]
RIN 2120-AA64

Airworthiness Directives; Various Model 234 and Model CH-47D 
Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for various 
Model 234 and Model CH-47D helicopters. This AD requires inspections of 
the pitch housing and revising the pitch housing retirement life. This 
AD was prompted by reports of cracking in the pitch housing lugs. The 
actions of this AD are intended to detect and prevent an unsafe 
condition on these products.

DATES: This AD is effective September 17, 2018.
    The Director of the Federal Register approved the incorporation by 
reference of certain documents listed in this AD as of September 17, 
2018.

ADDRESSES: For service information identified in this final rule, 
contact Boeing Helicopters, The Boeing Company, 1 S. Stewart Avenue, 
Ridley Park, PA 19078, telephone 610-591-2121, and Columbia 
Helicopters, Inc. (Columbia), 14452 Arndt Road NE, Aurora, OR 97002, 
telephone (503) 678-1222, fax (503) 678-5841, or at http://www.colheli.com. You may review a copy of the referenced service 
information at the FAA, Office of the Regional Counsel, Southwest 
Region, 10101 Hillwood Pkwy, Room 6N-321, Fort Worth, TX 76177.

Examining the AD Docket

    You may examine the AD docket on the internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2015-
4007; or in person at the Docket Operations Office between 9 a.m. and 5 
p.m., Monday through Friday, except Federal holidays. The AD docket

[[Page 39875]]

contains this AD, any incorporated-by-reference service information, 
the Special Airworthiness Information Bulletin (SAIB), the economic 
evaluation, any comments received, and other information. The street 
address for the Docket Operations Office (phone: 800-647-5527) is U.S. 
Department of Transportation, Docket Operations Office, M-30, West 
Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, 
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Chris Bonar, Aerospace Engineer, 
Airframe Section, Seattle ACO Branch, FAA, 2200 S 216th Street, Des 
Moines, WA 98198; telephone (206) 231-3521; email 
[email protected].

SUPPLEMENTARY INFORMATION: 

Discussion

    On March 14, 2017, at 82 FR 13567, the Federal Register published 
our notice of proposed rulemaking (NPRM), which proposed to amend 14 
CFR part 39 by adding an AD that would apply to Model 234 and Model CH-
47D helicopters with a pitch housing part number (P/N) 145R2075-11, 
145R2075-12, 145R2075-13, 145R2075-14, 145R2075-15, 145R2075-16, 
234R2075-1, or 234R2075-2 installed. The type certificate (TC) holder 
for Model 234 helicopters is Columbia (TC previously held by Boeing 
Defense & Space Group), and the TC holders for Model CH-47D helicopters 
currently include Columbia, Billings Flying Service, Inc., and Tandem 
Rotor, LLC. We did not limit the proposed AD to these TC holders 
because we expect additional TC holders of helicopters that are subject 
to this same unsafe condition.
    The NPRM was prompted by reports of cracking in the pitch housing 
lugs, located on the lead side of the lower vertical pin lug. The 
reports initially prompted the FAA to issue SAIB SW-11-03, dated 
October 22, 2010, which recommends that all owners and operators of 
Columbia Model 234 helicopters perform repetitive ultrasonic 
inspections of the lugs. At that time, there were no civil Model CH-47D 
helicopters in service. On March 20, 2015, we received a report of 
lateral vibration on a Model 234 helicopter caused by a crack in an aft 
pitch housing upper lug. The crack was determined to be caused by 
fatigue and attributed to underestimated load conditions in the 
original life limit calculations. This cracking differed from the 
cracking described in the SAIB.
    To correct this unsafe condition, we proposed to require repetitive 
eddy current and ultrasonic inspections of the pitch housing. Boeing, 
the original manufacturer of both model helicopters, developed service 
information for the SAIB ultrasonic inspections, which we proposed to 
require in the NPRM. Due to the rapid growth rate, an effective eddy 
current inspection must detect an inward-growing crack of no more than 
0.10 inch. The NPRM proposed to require, for Columbia helicopters, the 
eddy current inspection method specified in Columbia's service 
information. Because the other TC holders have not developed service 
instructions, we proposed to require the eddy current inspection 
procedures for all other helicopters be submitted to the Seattle or 
Denver Aircraft Certification Offices for approval.
    We also proposed to require removing the pitch housing from service 
when it accumulates a total of 8,200 hours time-in-service (TIS). 
Forward pitch housings on Model CH-47D helicopters had no life limit 
and the aft pitch housing already had a life limit of 8,200 hours TIS. 
For Model 234 helicopters, the forward pitch housing had a life limit 
of 12,547 hours TIS and the aft pitch housing had a life limit of 
19,077 hours TIS. The NPRM proposed to establish or reduce these life 
limits to 8,200 hours TIS for both forward and aft pitch housings, 
regardless of the model helicopter.
    The actions specified by the NPRM were intended to detect and 
prevent a crack in a pitch housing lug. This condition could result in 
loss of a rotor blade and consequent loss of helicopter control.
    Since the NPRM was issued, the FAA's Aircraft Certification Service 
has changed its organization structure. The new structure replaces 
product directorates with functional divisions. We have revised some of 
the office titles and nomenclature throughout this final rule to 
reflect the new organizational changes. Additional information about 
the new structure can be found in the Notice published on July 25, 2017 
(82 FR 34564).

Ex Parte Contact

    On October 25, 2017, after the comment period closed, we had a 
teleconference with Columbia about Columbia's service information 
identified in the NPRM. Columbia's comment during this teleconference 
is addressed below. A summary of this discussion can be found in the 
rulemaking docket at http://www.regulations.gov in Docket No. FAA-2015-
4007.

Comments

    We gave the public an opportunity to participate in developing this 
AD. The following presents the comments we received and the FAA's 
response to each comment.

Request

    One commenter supported the actions required by this AD.
    Another commenter requested that we provide more information 
regarding our determination to include all Model CH-47D and Model 234 
helicopters in this AD, including the number of hours on the failed 
Japanese military CH-47 pitch housing. This commenter suggested the 
failures may be unique to the Model 234 helicopter or may result from 
factors, such as high speed operations, a corrosive Japanese operating 
environment, or inaccurate fatigue equations.
    We agree to provide additional information regarding our 
determination. The Japanese military CH-47 pitch housing failure 
referenced in SAIB SW-11-03 failed due to fatigue cracking initiated by 
fretting. The event occurred in 2006, and we do not have access to the 
number of hours on the failed pitch housing. The reported pitch housing 
lug cracks occurred on both the Model 234 and the Model CH-47D. These 
models use identical rotor head design and components, including the 
same part-numbered pitch housings. Therefore, we determined that the 
life limits for the pitch housings on both models should be the same.
    We found no indication that the lug failure resulted from the 
Japanese operating environment. Investigation of the cracking did not 
show evidence of damage originating at corrosion sites. The Japanese 
operating environment is not unique as these aircraft operate worldwide 
in a variety of conditions. We also found no indications that the 
failures were due to inaccuracies in the Boeing Model 234 cycle count 
equations. Our investigation concluded that the original fatigue life 
evaluation excluded certain loading conditions and resulted in a life 
limit that was too high.
    Tandem Rotor requested the AD not impose a life limit on the 
forward pitch housing or, alternatively, impose a life limit consistent 
with the life limit of the MH-47E/G forward pitch housing of 24,975 
hours TIS. As part of this request, Tandem Rotor asks us to reconsider 
the service lives established by Boeing.
    We disagree. We reviewed newer analyses than those considered by 
Boeing, including fatigue loading that was not part of the original 
design data. These newer analyses show a life limit is required on both 
the forward and aft pitch housings. This is consistent with SAIB SW-11-
03, which included the

[[Page 39876]]

forward pitch housing despite cracks having only been found in service 
on the aft pitch housing. The newer analyses do not support the 24,975-
hour life limit requested by Tandem Rotor. These helicopters are used 
in a wide variety of operations. The life limits required by this AD 
assume more severe usage than the average operator in order to fully 
cover the range of different operators and usages. Individual operators 
may request an alternative method of compliance if sufficient data is 
submitted to substantiate a different life limit because their usage is 
not as damaging to a particular part.
    Tandem Rotor also requested that the repetitive ultrasonic 
inspection interval be increased from 200 hours to 250 hours TIS to 
align the inspection with an existing recurring 500-hour eddy current 
inspection, thus reducing travel costs and simplifying maintenance 
planning for the technician.
    We disagree. We have determined that the 200-hour interval for the 
inspection represents an appropriate time in which the required actions 
can be performed in a timely manner within the affected fleet, while 
still maintaining an adequate level of safety. A 250-hour interval did 
not yield a sufficient safety margin when considering all usage 
spectrums in the current fleet.
    Columbia requested that we change the AD to make the eddy current 
inspection requirement the same for all helicopters. In support of its 
request, Columbia states that its service bulletin is proprietary and 
should not be incorporated by reference (and thus made publicly 
available) as an inspection method in the AD.
    We agree. The inspection methods in the Columbia service 
information is specific to Columbia helicopters. Because Columbia is 
the only operator of its U.S. fleet, we determined there are no other 
operators that need this information to perform the eddy current 
inspections. We have changed the AD accordingly.

FAA's Determination

    We have reviewed the relevant information, considered the comments 
received, and determined that an unsafe condition exists and is likely 
to exist or develop on other products of these same type designs and 
that air safety and the public interest require adopting the AD with 
the change previously described. This change will not increase the 
economic burden on any operator or increase the scope of the AD.

Related Service Information Under 1 CFR Part 51

    We reviewed Boeing Service Bulletin 145R2075-62-0001, Revision 1, 
dated September 27, 2011, which specifies updated life limits for the 
forward and aft pitch housings and revised overhaul and ultrasonic 
inspection procedures for various military Model CH-47 and Model 234 
helicopters.
    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.

Other Related Service Information

    We also reviewed Columbia Helicopters, Inc. Alert Service Bulletin 
No. 234-62-A0012, Revision 2, dated March 1, 2016, and Alert Service 
Bulletin No. 47D-62-A0002, Revision 0, dated March 1, 2016. This 
service information specifies performing repetitive eddy current 
inspections, visual inspections, and ultrasonic inspections and for 
reducing the life limit of the pitch housing assemblies.

Differences Between This AD and the Service Information

    The service information provides different life limits for the 
forward and aft pitch housings, while this AD requires a life limit of 
8,200 hours TIS for all pitch housings. The service information 
requires either an ultrasonic inspection or a dye penetrant inspection 
as part of the overhaul procedures. The service information specifies 
different compliance times for the inspections than what this AD 
requires.

Costs of Compliance

    We estimate that this AD affects 15 helicopters of U.S. Registry 
and that labor costs average $85 per work-hour. Based on these 
estimates, we expect the following costs:
     An eddy current inspection requires 4 work-hours for a 
total cost of $340 per helicopter and $5,100 for the U.S. fleet, per 
inspection cycle.
     An ultrasonic inspection requires 4 work-hours for a total 
cost of $340 per helicopter and $5,100 for the U.S. fleet, per 
inspection cycle.
     Replacing a pitch housing requires 8 work-hours and parts 
cost $13,000, for a total cost of $13,680 per helicopter.

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

    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) 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.

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):

[[Page 39877]]

2018-16-11 Various Model 234 and Model CH-47D Helicopters: Amendment 
39-19351; Docket No. FAA-2015-4007; Product Identifier 2015-SW-064-
AD.

(a) Applicability

    This AD applies to Model 234 and Model CH-47D helicopters, 
regardless of type certificate holder, with a pitch housing assembly 
(pitch housing) part number (P/N) 145R2075-11, 145R2075-12, 
145R2075-13, 145R2075-14, 145R2075-15, 145R2075-16, 234R2075-1, or 
234R2075-2 installed, certificated in any category.

(b) Unsafe Condition

    This AD defines the unsafe condition as a crack in a pitch 
housing lug. This condition could result in loss of a rotor blade 
and consequent loss of helicopter control.

(c) Effective Date

    This AD becomes effective September 17, 2018.

(d) Compliance

    You are responsible for performing each action required by this 
AD within the specified compliance time unless it has already been 
accomplished prior to that time.

(e) Required Actions

    (1) Before further flight, remove from service any pitch housing 
P/N 145R2075-11, 145R2075-12, 145R2075-13, 145R2075-14, 145R2075-15, 
145R2075-16, 234R2075-1, and 234R2075-2 that has accumulated 8,200 
hours total time-in-service (TIS).
    (2) Before the pitch housing accumulates 200 hours TIS after the 
effective date of this AD and thereafter at intervals not to exceed 
200 hours TIS, ultrasonic inspect the pitch housing for a crack in 
accordance with Attachment 1, paragraphs F and H through K, of 
Boeing Service Bulletin 145R2075-62-0001, Revision 1, dated 
September 27, 2011. If there is a crack, replace the pitch housing 
before further flight.
    (3) Within 400 hours TIS after the effective date of this AD or 
before the pitch housing has accumulated 4,000 hours total TIS, 
whichever occurs later, and thereafter at intervals not to exceed 
500 hours TIS, eddy current inspect the pitch housing for a crack. 
If there is a crack, replace the pitch housing before further 
flight. The eddy current inspection must be accomplished using a 
method approved by the Manager, Seattle ACO Branch, or by the 
Manager, Denver ACO Branch. For a repair method to be approved as 
required by this AD, the manager's approval letter must specifically 
refer to this AD.

 (f) Alternative Methods of Compliance (AMOCs)

    (1) For operators of helicopters with type certificates issued 
by the Denver Aircraft Certificate Office or ACO Branch, the manager 
of the Denver ACO Branch, FAA, may approve AMOCs for this AD. Send 
your proposal to: Greg Johnson, Senior Aerospace Engineer, Denver 
ACO Branch, Compliance and Airworthiness Division, FAA, 26805 East 
68th Avenue, Denver, CO 80249; phone: 303-342-1083; fax: 303-342-
1088; email: [email protected].
    (2) All other AMOC requests should be sent to the Manager, 
Seattle ACO Branch, FAA. Send your proposal to: Chris Bonar, 
Aerospace Engineer, Airframe Section, Seattle ACO Branch, FAA, 2200 
S 216th Street, Des Moines, WA 98198; telephone (206) 231-3521; 
email [email protected].
    (3) For operations conducted under a 14 CFR part 119 operating 
certificate or under 14 CFR part 91, subpart K, we suggest that you 
notify your principal inspector, or lacking a principal inspector, 
the manager of the local flight standards district office or 
certificate holding district office before operating any aircraft 
complying with this AD through an AMOC.

(g) Additional Information

    Special Airworthiness Information Bulletin SW-11-03, dated 
October 22, 2010 (SAIB); Columbia Helicopters, Inc., Alert Service 
Bulletin No. 234-62-A0012, Revision 2, dated March 1, 2016; and 
Columbia Helicopters, Inc., Alert Service Bulletin No. 47D-62-A0002, 
Revision 0, dated March 1, 2016, which are not incorporated by 
reference, contain additional information about the subject of this 
AD. You may view the SAIB on the internet at http://www.regulations.gov in the AD Docket. For Columbia service 
information identified in this final rule, contact Columbia 
Helicopters, Inc., 14452 Arndt Road NE, Aurora, OR 97002, telephone 
(503) 678-1222, fax (503) 678-5841, or at http://www.colheli.com. 
You may view a copy of the referenced service information at the 
FAA, Office of the Regional Counsel, Southwest Region, 10101 
Hillwood Pkwy, Room 6N-321, Fort Worth, TX 76177.

 (h) Subject

    Joint Aircraft Service Component (JASC) Code: 6220, Main Rotor 
Head.

(i) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference 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) Boeing Service Bulletin 145R2075-62-0001, Revision 1, dated 
September 27, 2011.
    (ii) Reserved.
    (3) For Boeing Helicopters service information identified in 
this AD, contact Boeing Helicopters, The Boeing Company, 1 S. 
Stewart Avenue, Ridley Park, PA 19078, telephone 610-591-2121.
    (4) You may view this service information at FAA, Office of the 
Regional Counsel, Southwest Region, 10101 Hillwood Pkwy, Room 6N-
321, Fort Worth, TX 76177. For information on the availability of 
this material at the FAA, call (817) 222-5110.
    (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, call (202) 741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued in Fort Worth, Texas, on July 27, 2018.
Scott A. Horn,
Deputy Director for Regulatory Operations, Compliance & Airworthiness 
Division, Aircraft Certification Service.
[FR Doc. 2018-17112 Filed 8-10-18; 8:45 am]
 BILLING CODE 4910-13-P