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 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 

Model480 helicopters with a serial number (SIN) 5001 through 5006; with a ·n rotor spindle 

(spindle), part number (PIN) 28-14282-11 or PIN 28-14282-13. 

Background 

This EAD was prompted by a f:<>t"-"~"'"' 

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 of time before the 

separation. This EA , conducting a magnetic particle inspection (MPI) 

to determine if a crac spi that has 5,000 or more hours time-in-service (TIS) or 

where the hours TIS o pi tll 1s not known. If there 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 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 

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 Bulletin No. T-050, 

dated February 11, 2015, for Model480 helicopters, SIN 5001 through 5004 and 5006, and with a 

spindle, PIN 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 NAS41 0 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 

Interim Action 

eventually to devel 

identified, we might 

nte c Ion. The inspection reports that are required by this 

IHJiem~ll ins into the root cause and extent of the cracking, and 

1 c · n o address the unsafe condition. Once final action has been 

sider 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 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 ofthe Agency's authority. 

We are issuing this rulemaking under the authority described in "Subtitle VII, Part A, 

Subpart III, Section 44 701, 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. 

2 
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. 

2015-04-51 The Enstrom Helicopter Corporation (Enstrom): Directorate Identifier 20 15-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 

~~=le with 5,000 or more hours time-in-service (TIS) or where the r n fthe spindle is not 

(b) Unsafe Condition n u ~d h · not detected, could 

'"'" .... 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 it has already been accomplished 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 NAS41 0 

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. 

4 
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 w 

Who Performed the Inspection: 

Date and Location Inspection was Acco1Jl£n1Sh' 

Crack Found? If yes, describe t 

Provide Any Other Co m ts 

Issued in Fort Worth, 

Lance T. Gant, 

Acting Manager, Rotorcraft Directorate, 

Aircraft Certification Service.