
[Federal Register Volume 82, Number 40 (Thursday, March 2, 2017)]
[Proposed Rules]
[Pages 12308-12310]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-03950]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-0141; Directorate Identifier 2016-SW-067-AD]
RIN 2120-AA64


Airworthiness Directives; The Enstrom Helicopter Corporation

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: We propose to supersede airworthiness directive (AD) 2015-08-
51 for Enstrom Helicopter Corporation (Enstrom) Model F-28A, 280, F-
28C, F-28C-2, F-28C-2R, 280C, F-28F, F-28F-R, 280F, 280FX, and 480 
helicopters. AD 2015-08-51 requires an inspection of the main rotor 
spindle (spindle) and reporting the inspection results to the FAA. This 
proposed AD was prompted by additional reports of cracked spindles and 
would require establishing a life limit and a recurring inspection. 
These proposed actions are intended to prevent the unsafe condition on 
these products.

DATES: We must receive comments on this proposed AD by May 1, 2017.

ADDRESSES: You may send comments by any of the following methods:
     Federal eRulemaking Docket: Go to http://www.regulations.gov. Follow the online instructions for sending your 
comments electronically.
     Fax: 202-493-2251.
     Mail: Send comments to the U.S. Department of 
Transportation, Docket Operations, M-30, West Building Ground Floor, 
Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590-0001.
     Hand Delivery: Deliver to the ``Mail'' address between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

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-2017-
0141; 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 
contains this proposed AD, the economic evaluation, any comments 
received and other information. The street address for the Docket 
Operations Office (telephone 800-647-5527) is in the ADDRESSES section. 
Comments will be available in the AD docket shortly after receipt.
    For service information identified in this proposed rule, contact 
Enstrom Helicopter Corporation, 2209 22nd Street, Menominee, MI; 
telephone (906) 863-1200; fax (906) 863-6821; or at 
www.enstromhelicopter.com. You may review service information at the 
FAA, Office of the Regional Counsel, Southwest Region, 10101 Hillwood 
Pkwy., Room 6N-321, Fort Worth, TX 76177.

FOR FURTHER INFORMATION CONTACT: Monica Nemecek, Continued Operational 
Safety Program Manager, Chicago Aircraft Certification Office, Small 
Airplane Directorate, FAA, 2300 East Devon Ave., Des Plaines, IL 60018; 
(847) 294-7618; email 9-AGL-CHI-ACO-COS@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to participate in this rulemaking by submitting 
written comments, data, or views. We also invite comments relating to 
the economic, environmental, energy, or federalism impacts that might 
result from adopting the proposals in this document. The most helpful 
comments reference a specific portion of the proposal, explain the 
reason for any recommended change, and include supporting data. To 
ensure the docket does not contain duplicate comments, commenters 
should send only one copy of written comments, or if comments are filed 
electronically, commenters should submit only one time.
    We will file in the docket all comments that we receive, as well as 
a report summarizing each substantive public contact with FAA personnel 
concerning this proposed rulemaking. Before acting on this proposal, we 
will consider all comments we receive on or before the closing date for 
comments. We will consider comments filed after the comment period has 
closed if it is possible to do so without incurring expense or delay. 
We may change this proposal in light of the comments we receive.

Discussion

    On May 8, 2015, we issued AD 2015-08-51, Amendment 39-18160 (80 FR 
28172, May 18, 2015), which was sent previously as an emergency AD to 
all known U.S. owners and operators of Enstrom Model F-28A, 280, F-28C, 
F-28C-2, F-28C-2R, 280C, F-28F, F-28F-R, 280F, 280FX, and 480 
helicopters. AD 2015-08-51 applies to helicopters with a spindle part 
number (P/N) 28-14282-11 or 28-14282-13 installed and requires 
conducting a one-time magnetic particle inspection (MPI) of the spindle 
for cracks and reporting the inspection results to the FAA. AD 2015-08-
51 was prompted by a fatal accident and reports of spindles with 
cracks. The actions of AD 2015-08-51 are intended to detect a crack in 
a spindle and prevent loss of a main rotor blade and subsequent loss of 
control of the helicopter.

Actions Since AD 2015-08-51 Was Issued

    Since we issued AD 2015-08-51, we received additional reports of 
cracked spindles. Additionally, Enstrom revised its service information 
to reduce the time for the initial MPI from 3,500 hours TIS to 1,500 
hours TIS and extend the compliance time for a recurring MPI of the 
spindles from 300 hours TIS to 500 hours TIS. Based on a review of the 
in-service data and a fatigue analysis, the FAA determined a life limit 
and repetitive MPIs were necessary to reduce the risk of a crack 
developing in a spindle. We also determined the reporting requirement 
in AD 2015-08-51 is no longer necessary.
    We issued AD 2015-08-51 as interim action; this proposed AD would 
provide long-term requirements to prevent a spindle failure. 
Accordingly, this

[[Page 12309]]

proposed AD would require an MPI of the spindle every 500 hours TIS 
until the spindle reaches its new life limit of 1,500 hours TIS. These 
proposed actions are intended to detect a crack in a spindle and 
prevent loss of a main rotor blade and subsequent loss of control of 
the helicopter.

FAA's Determination

    We are proposing this AD because we evaluated all the relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of these same type 
designs.

Related Service Information

    We reviewed Enstrom Service Directive Bulletin No. 0119, Revision 
3, dated June 24, 2016, for Model F-28A, F-28C, F-28F, 280, 280C, 280F, 
and 280FX helicopters with a spindle P/N 28-14282-11 or 28-14282-13. We 
also reviewed Enstrom Service Directive Bulletin No. T-050, Revision 3, 
dated June 24, 2016, for Model 480 helicopters, serial numbers 5001 
through 5004 and 5006, and with a spindle P/N 28-14282-13, except those 
aircraft modified with tension-torsion straps. Both service directive 
bulletins specify sending the spindle to Enstrom for an MPI before the 
spindle reaches 1,500 hours time-in-service (TIS), or within 5 hours 
TIS for those spindles with 1,500 or more hours TIS. Thereafter, the 
service directive bulletins specify returning the spindle to Enstrom 
for an MPI every 500 hours.

Proposed AD Requirements

    This proposed AD would require establishing a life limit of 1,500 
hours TIS for spindle P/Ns 28-14282-11 and 28-14282-13. This proposed 
AD would also require an initial and recurring MPI of the spindles.

Differences Between This Proposed AD and the Service Information

    This proposed AD would require establishing a spindle life limit of 
1,500 hours TIS. The service information does not specify a life limit.
    This proposed AD would require that the MPI be conducted by a Level 
II or Level III inspector or equivalent. The service information 
specifies sending the spindle to Enstrom for an MPI.
    This proposed AD would require an initial MPI before further flight 
for a spindle with 500 or more hours TIS, unless an MPI has been done 
within the last 500 hours TIS. The service information specifies an 
initial MPI compliance time of within 5 hours TIS for a spindle with 
1,500 or more hours TIS.

Costs of Compliance

    We estimate that this proposed AD would affect 323 helicopters of 
U.S. Registry. We estimate that operators may incur the following costs 
in order to comply with this AD. Labor costs are estimated at $85 per 
work-hour. Inspecting the spindles would take about 15 work-hours for 
an estimated cost of $1,275 per helicopter and $411,825 for the U.S. 
fleet per inspection cycle. Replacing a cracked spindle would cost 
$8,164 for parts and no additional work-hours. Replacing a set of three 
spindles that have reached their life limit would take about 14 work-
hours and parts would cost $17,500 for a total cost of $18,690 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

    We determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would 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, I certify this proposed regulation:
    1. Is not a ``significant regulatory action'' under Executive Order 
12866;
    2. Is not a ``significant rule'' under the 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 proposed 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.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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 removing Airworthiness Directive (AD) 
2015-08-51, Amendment 39-18160 (80 FR 28172, May 18, 2015), and adding 
the following new AD:

The Enstrom Helicopter Corporation (Enstrom): Docket No. FAA-2017-
0141; Directorate Identifier 2016-SW-067-AD.

(a) Applicability

    This AD applies to Enstrom Model F-28A, 280, F-28C, F-28C-2, F-
28C-2R, 280C, F-28F, F-28F-R, 280F, and 280FX helicopters, all 
serial numbers; and Enstrom Model 480 helicopters, serial numbers 
5001 through 5006; with a main rotor spindle (spindle) part number 
(P/N) 28-14282-11 or 28-14282-13, installed, certificated in any 
category.

(b) Unsafe Condition

    This AD defines the unsafe condition as a crack in a spindle, 
which, if not detected, could result in loss of a main rotor blade 
and subsequent loss of control of the helicopter.

(c) Affected ADs

    This AD supersedes AD 2015-08-51, Amendment 39-18160 (80 FR 
28172, May 18, 2015).

(d) Comments Due Date

    We must receive comments by May 1, 2017.

(e) 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.

(f) Required Actions

    (1) Before further flight, remove from service any spindle P/N 
28-14282-11 or 28-14282-13 that has 1,500 or more hours time-in-
service (TIS). If the hours TIS of a spindle is unknown, use the TIS 
of the helicopter.

[[Page 12310]]

Thereafter, remove from service any spindle P/N 28-14282-11 or 28-
14282-13 before accumulating 1,500 hours TIS.
    (2) For each spindle with 500 or more hours TIS, using the hours 
TIS of the helicopter if the hours TIS of the spindle is unknown:
    (i) Before further flight, unless already done within the last 
500 hours TIS, conduct a magnetic particle inspection (MPI) of the 
spindle for a crack, paying particular attention to the threaded 
portion of the spindle. The MPI of the spindle must be conducted by 
a Level II or Level III inspector qualified in the MPI in the 
Aeronautics Sector according to the EN4179 or NAS410 standard or 
equivalent. If there is a crack in the spindle, replace it with an 
airworthy spindle before further flight.
    (ii) Thereafter at intervals not to exceed 500 hours TIS, repeat 
the MPI specified in paragraph (f)(2)(i) of this AD.

(g) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Chicago Aircraft Certification Office, FAA, may 
approve AMOCs for this AD. Send your proposal to: Monica Nemecek, 
Continued Operational Safety Program Manager, Chicago Aircraft 
Certification Office, Small Airplane Directorate, FAA, 2300 East 
Devon Ave., Des Plaines, IL 60018; (847) 294-7618; email 9-AGL-CHI-ACO-COS@faa.gov.
    (2) 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.
    (3) AMOCs approved previously in accordance with AD 2015-08-51, 
Amendment 39-18160 (80 FR 28172, May 18, 2015), are approved as 
AMOCs for the corresponding requirements in paragraph (f) of this 
AD.

(h) Additional Information

    Enstrom Service Directive Bulletin Nos. 0119 and T-050, both 
Revision 3 and both dated June 24, 2016, which are not incorporated 
by reference, contain additional information about the subject of 
this AD. For service information identified in this AD, contact 
Enstrom Helicopter Corporation, 2209 22nd Street, Menominee, MI; 
telephone (906) 863-1200; fax (906) 863-6821; or at 
www.enstromhelicopter.com. You may review the service information at 
the FAA, Office of the Regional Counsel, Southwest Region, 10101 
Hillwood Pkwy., Room 6N-321, Fort Worth, TX 76177.

(i) Subject

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


    Issued in Fort Worth, Texas, on February 16, 2017.
Lance T. Gant,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 2017-03950 Filed 3-1-17; 8:45 am]
BILLING CODE 4910-13-P


