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2015-04-51 THE ENSTROM HELICOPTER CORPORATION (ENSTROM): ( e m e r g e n c y )
Directorate Identifier 2015-SW-02-AD. 
(a) APPLICABILITY

    This EAD 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 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.  This EAD only
    applies to any helicopter that has a spindle with 5,000 or more  hours
    time-in-service (TIS)  or where  the hours  TIS of  the spindle is not
    known.

(b) UNSAFE CONDITION

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

(c) EFFECTIVE DATE

    This EAD is effective upon receipt.

(d) COMPLIANCE

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

(e) REQUIRED ACTIONS

(1) Before  further  flight,  conduct a magnetic particle inspection (MPI)
    the spindle to  determine if a  crack exists. 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. If  there is  a crack  in the  spindle, replace  it with  an
    airworthy spindle before further flight.

(2) Within 72 hours after accomplishing the MPI,  report  the  information
    requested in Appendix 1  to this EAD by  mail to the Manager,  Chicago
    Aircraft Certification Office, Federal Aviation Administration,  ATTN:
    Gregory J. Michalik, 2300 East Devon Ave., Des Plaines, IL, 60018;  by
    fax to (847) 294-7834; or email to gregory.michalik@faa.gov.

(f) ALTERNATIVE METHODS OF COMPLIANCE (AMOCS)

(1) The Manager, Chicago Aircraft Certification Office,  FAA,  may approve
    AMOCs for this EAD. Send your proposal to: Gregory J. Michalik, Senior
    Aerospace  Engineer,  Chicago  Aircraft  Certification  Office,  Small
    Airplane Directorate FAA, 2300 East Devon Ave, Des Plaines, IL, 60018;
    (847) 294-7135; email gregory.michalik@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 EAD
    through an AMOC.

(g) ADDITIONAL INFORMATION

    For further information contact: Gregory J. Michalik, Senior Aerospace
    Engineer,   Chicago  Aircraft  Certification  Office,  Small  Airplane
    Directorate, FAA, 2300 East Devon Ave., Des Plaines, IL, 60018,  (847)
    294-7135; email Gregory.michalik@faa.gov.

(h) SUBJECT

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

APPENDIX 1 TO AD 2014-04-51

SPINDLE INSPECTION (SAMPLE FORMAT)

Provide the following information by mail to the Manager, Chicago Aircraft
Certification Office,  Federal Aviation  Administration, ATTN:  Gregory J.
Michalik,  2300 East Devon Ave., Des Plaines, IL, 60018;  by fax to  (847)
294-7834; or email to gregory.michalik@faa.gov.

Aircraft Registration No.:
Helicopter Model:
Helicopter Serial Number:
Helicopter Owner or Operator:
Contact Phone No.:
Spindle Part Number and Serial Number:
Total Hours Time-in-Service (TIS) on Spindle:
Total Hours TIS on Helicopter(if hours TIS on spindle were not available):
Who Performed the Inspection:
Date and Location Inspection was Accomplished:
Crack Found?  If yes, describe the crack size, location, orientation (pro-
vide a sketch or picture):
Provide Any Other Comments:

Issued in Fort Worth, Texas, on February 12, 2015.  Lance T. Gant,  Acting
Manager, Rotorcraft Directorate, Aircraft Certification Service.
PREAMBLE 

DATE: February 12, 2015
AD #: 2015-04-51

This emergency airworthiness directive (EAD) 2015-04-51 is being sent to
owners and operators of The Enstrom Helicopter Corporation (Enstrom)
Enstrom Model F-28A, 280, F-28C, F-28C-2, F-28C-2R, 280C, F-28F, F-28F-R,
280F, 280FX helicopters, all serial numbers; and Model 480 helicopters
with a serial number (S/N) 5001 through 5006; with a main rotor spindle
(spindle), part number (P/N) 28-14282-11 or P/N 28-14282-13.

Background

This EAD was prompted by a fatal accident. The investigation is ongoing,
however, preliminary results indicate that the accident was caused by a
crack in the spindle which resulted in the main rotor blade separating
from the helicopter. The crack was discovered at the last thread of the
spindle retention nut threads. While the investigation could not determine
when the crack initiated, it was able to determine that the crack existed,
undetected, for a significant amount of time before the separation. This
EAD requires, before further flight, conducting a magnetic particle
inspection (MPI) to determine if a crack exists in any spindle that has
5,000 or more hours time-in-service (TIS) or where the hours TIS of the
spindle is not known. If there is a crack in the spindle, replacing it
before further flight is required. Reporting the inspection results to the
FAA is also required within 72 hours. These EAD actions are intended to
detect a crack in the spindle which could result in loss of a main rotor
blade and subsequent loss of control of the helicopter.

FAA’s Determination

We are issuing this EAD 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

Enstrom has issued Service Directive Bulletin No. 0119, dated February 11,
2015, for all S/Ned Model F-28A, F-28C, F-28F, 280, 280C, 280F, and 280FX
helicopters with a spindle, P/N 28-14282-11 and 28-14282-13. Enstrom has
also issued Service Directive Bulletin No. T-050, dated February 11, 2015,
for Model 480 helicopters, S/N 5001 through 5004 and 5006, and with a
spindle, P/N 28-14282-13, except those aircraft modified with tension
-torsion straps. Both service directives specify, for any spindle that has
5,000 hours or more hours TIS, within 5 hours TIS, sending the spindle to
Enstrom for an MPI. For any spindle with less than 5,000 hours TIS, the
service directives specify sending the spindle to Enstrom for an MPI
before it reaches 5,000 hours TIS.

EAD Requirements

This EAD requires, before further flight, conducting an MPI to determine
if a crack exists in any spindle that has 5,000 or more hours TIS or where
the hours TIS of the spindle is not known. If there is a crack in the
spindle, replacing it before further flight is required. The MPI of the
spindle must be conducted by a Level II or Level III inspector qualified
in the MPI method in the Aeronautics Sector according to the EN4179 or
NAS410 standard. This EAD also requires, within 72 hours, reporting
certain information to the FAA.

Costs of Compliance

We estimate that this AD affects 323 helicopters of U.S. Registry and that
operators may incur the following costs to comply with this AD. Inspecting
each spindle will require 15 work-hours at an average labor rate of $85
per work-hour and the cost to report the required inspection information
is $43, for a total of $1,318 per helicopter and 425,714 for the U.S
fleet. If replacing a spindle is required, it will take 4 work-hours and
$8,164 for parts, for a total of $8,504 per helicopter.

Differences Between This EAD and the Service Information

This EAD requires that the MPI be conducted by a Level II or Level III
inspector and that the results of the MPI be reported to the FAA, whereas
the service information requires that the MPI be accomplished by Enstrom.
This EAD requires the MPI before further flight; the service information
specifies that it be accomplished within 5 hours TIS.

Interim Action

We consider this EAD to be an interim action. The inspection reports that
are required by this EAD will enable us to obtain better insight into the
root cause and extent of the cracking, and eventually to develop final
action to address the unsafe condition. Once final action has been
identified, we might consider further rulemaking.

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 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
current valid OMB control number. The control number for the collection of
information required by this EAD is 2120-0056. The paperwork cost
associated with this EAD has been detailed in the Costs of Compliance
section of this document and includes time for reviewing instructions, as
well as completing and reviewing the collection of information. Therefore,
all reporting required by this EAD is mandatory. Comments concerning the
accuracy of this burden and suggestions for reducing the burden should be
directed to the FAA at 800 Independence Ave., SW, Washington, DC 20591;
ATTN: Information Collection Clearance Officer, AES-200.

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.

Adoption of the Emergency Airworthiness Directive (EAD)

We are issuing this EAD under 49 U.S.C. Sections 106(g), 40113, and 44701
according to the authority delegated to me by the Administrator.