### FAA Aviation Safety

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

## EMERGENCY AIRWORTHINESS DIRECTIVE

www.faa.gov /aircraft/safety /alerts/



### This emergency airworthiness directive (EAD) 2015-04-51 is being sent to owners and operators ofThe 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 Model480 helicopters with a serial number (SIN) 5001 through 5006; with a ·nrotor spindle (spindle), partnumber (PIN) 28-14282-11 or 

### PIN 28-14282-13. Background This EAD was prompted by a

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### preliminary results indicate tha d the main rotor blade se r spindle retention nut hre s rmine when the crack initiated, it was able to determi r a significant amount oftime before the separation. This EA , conducting a magnetic particle inspection (MPI) to determine ifa crac spi that has 5,000 or more hours time-in-service (TIS) or where the hours TIS o pi tll 

### 1s not known. Ifthere is a crack in the spindle, replacing it before further flight is reqm e 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 ofa main rotor blade and subsequent loss ofcontrol ofthe 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 otherproducts ofthese same type designs. Related Service Information Enstrom has issued Service Directive BulletinNo. 0119, dated February 11, 2015, for all SINed Model F-28A, F-28C, F-28F, 280, 280C, 280F, and 280FX helicopters with a spindle, 

### PIN 28-14282-11 and 28-14282-13. Enstrom has also issued Service Directive BulletinNo. T-050, dated February 11, 2015, for Model480 helicopters, SIN 5001 through 5004 and 5006, and with a spindle, 

### PIN28-14282-13, exceptthose aircraft modified with tension-torsion straps. Both service directives specify, for any spindle that has 5,000 hours or more hours TIS, within 5hours 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 ifa crack exists in any spindle that has 5,000 or more hours TIS or where the hours TIS ofthe spindle is not known. If there is a crack in the spindle, replacing it before further flight is required. The MPI ofthe spindlemust be conducted by a Level II orLevel III inspector qualified in the MPI method in the Aeronautics Sector according to the EN4179 orNAS410 standard. This EAD also requires, within 72 hours, reporting certain informationto the FAA. 

### Costs ofCompliance We estimate thatthis AD affects 323 helicopters ofU.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 laborrate of$85 perwork-hour and the cost to report the required inspection information is $43, for a total of$1,318 perhelicopter and 425,714 for the U.S fleet. Ifreplacing a spindle is required, it will take 4 work-hours and $8,164 for parts, for a total of$8,504 perhelicopter. Differences Between This EAD and the Service Information

Interim Action

eventually to devel identified, we might nte c Ion. The inspectionreports that are required by this**IHJiem~ll** ins into the root cause and extent ofthe cracking, and 1 c · n o address the unsafe condition. Once final action has been siderfurther 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 ofinformation subjectto the requirements ofthe Paperwork Reduction Act unless that collection ofinformation displays a current valid OMB control number. The control numberfor the collection ofinformationrequired by this EAD is 2120-0056. The paperwork cost associated withthis EAD has been detailed in the Costs ofCompliance section ofthis document and includes time for reviewing instructions, as well as completing and reviewing the collection ofinformation. Therefore, all reporting required by this EAD is mandatory. Comments concerning the accuracy ofthis 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 ofthe United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority ofthe FAA Administrator. "Subtitle VII, Aviation Programs," describes in more detail the scope oftheAgency's authority.
We are issuing this rulemaking under the authority described in "Subtitle VII, Part A, Subpart III, Section 44701, General requirements." Underthat section, Congress charges the FAA with promoting safe flight ofcivil 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 ofthat authority because it addresses an unsafe conditionthat is likely to exist ordevelop onproducts identified in this rulemaking action.

2Adoption ofthe 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. 2015-04-51 The Enstrom Helicopter Corporation (Enstrom): 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 Model480 helicopters, serial numbers 5001 through 5006; with a main rotor spindle (spindle), part number (PIN) 28-14282-11 or 28-14282-13, installed, certificated in any category. This EAD only applies to helicopter that has

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....1.-KMI of copter. (c) Effective This EAD is (d) Complia You are responsible for performing each action required by this EAD within the specified compliance time unless ithas already been accomplishedprior to that time. (e) Required Actions (1) Before further flight, conduct a magnetic particle inspection (MPI) the spindle to determine ifa crack exists. The MPI ofthe spindle must be conducted by a Level II orLevel III inspector qualified in the MPI inthe Aeronautics Sector according to the EN4179 orNAS410 standard. Ifthere is a crack inthe spindle, replace it with an airworthy spindle before further flight. (2) Within 72 hours after accomplishing the MPI, report the information requested in Appendix 1to this EAD by mail to the Manager, Chicago Aircraft Certification Office, Federal Aviation Administration, ATTN: Gregory J. Michalik, 2300 East DevonAve., Des Plaines, IL, 60018; by fax to (847) 294-7834; oremail to gregory.michalik@faa.gov

.. (f) Alternative Methods ofCompliance (AMOCs) (1) The Manager, Chicago Aircraft Certification Office, FAA, may approve AMOCs for this EAD. Send yourproposal to: Gregory J. Michalik, SeniorAerospace 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 CFRpart 119 operating certificate orunder 14 CFR part 91, subpart K, we suggest that you notify yourprincipal inspector, or lacking a principal inspector, the manager ofthe 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, SeniorAerospace 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.

4Appendix 1to AD 2014-04-51 Spindle Inspection (Sample Format) Providethe following informationbymail to the Manager, Chicago Aircraft Certification Office, Federal AviationAdministration, ATTN: Gregory 

### J. Michalik, 2300 East DevonAve., Des Plaines, IL, 60018; byfax to (847) 294-7834; oremailto gregory.michalik@faa.gov. Aircraft RegistrationNo.: HelicopterModel: Helicopter Serial Number: Helicopter Owner orOperator: ContactPhoneNo.: Spindle PartNumber and SerialNumber: Total Hours Time-in-Service (TIS) on Spindle: Total Hours TIS onHelicopter (ifhours TIS on spindle w Who Performedthe Inspection: Date and LocationInspection was Acco1Jl£n1Sh' CrackFound? Ifyes, describe t Provide Any OtherCo m ts

Issued inFort Worth,

Lance T. Gant, Acting Manager, RotorcraftDirectorate, Aircraft Certification Service.