[Federal Register Volume 59, Number 9 (Thursday, January 13, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-141]


[[Page Unknown]]

[Federal Register: January 13, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 93-SW-21-AD; Amendment 39-8766; AD 93-15-10]

 

Airworthiness Directives; Enstrom Helicopter Corporation Model F-
28A, F-28C, F-28C2, F-28F, 280, 280C, 280F, and 280FX Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This document publishes in the Federal Register an amendment 
adopting Airworthiness Directive (AD) 93-15-10 that was sent previously 
to all known U.S. owners and operators of The Enstrom Helicopter 
Corporation Model F-28A, F-28C, F-28C2, F-28F, 280, 280C, 280F, and 
280FX helicopters by individual letters. This AD requires an initial 
inspection of the composite-wrapped main rotor shaft for composite- 
wrapping separation, red color residue, corrosion, or cracks, and 
replacement of certain main rotor shafts. This amendment is prompted by 
the discovery of a significant crack in a composite-wrapped main rotor 
shaft. The actions specified by this AD are intended to prevent failure 
of the main rotor shaft, loss of the main rotor, and subsequent loss of 
control of the helicopter.

DATES: Effective January 28, 1994, to all persons except those persons 
to whom it was made immediately effective by Priority Letter AD 93-15-
10, issued on August 3, 1993, which contained the requirements of this 
amendment.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of January 28, 1994.
    Comments for inclusion in the Rules Docket must be received on or 
before March 14, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Assistant Chief Counsel, Attention: 
Rules Docket No. 93-SW-21-AD, 2601 Meacham Boulevard, room 663, Fort 
Worth, Texas 76137.
    The applicable service information may be obtained from The Enstrom 
Helicopter Corporation, Twin County Airport, P.O. Box 490, Menominee, 
Michigan 49858. This information may be examined at the FAA, Office of 
the Assistant Chief Counsel, 2601 Meacham Boulevard, room 663, Fort 
Worth, Texas; or at the Office of the Federal Register, 800 North 
Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Mr. Joe McGarvey, Aerospace Engineer, 
Chicago Aircraft Certification Office, FAA, Airframe Branch, Small 
Airplane Directorate, 2300 East Devon Avenue, room 232, Des Plaines, 
Illinois 60018, telephone (708) 294-7136, fax (708) 294-7834.

SUPPLEMENTARY INFORMATION: On August 3, 1993, the FAA issued Priority 
Letter AD 93-15-10, applicable to The Enstrom Helicopter Corporation 
Model F-28A, F-28C, F-28C2, F-28F, 280, 280C, 280F, and 280FX 
helicopters, which requires an initial inspection of the composite-
wrapped main rotor shaft (shaft) for composite-wrapping separations, 
red color residue, corrosion, or cracks, and replacement of certain 
shafts. That action was prompted by the discovery of a significant 
crack in a shaft. This condition, if not corrected, could result in 
failure of the shaft, loss of the main rotor, and subsequent loss of 
control of the helicopter.
    The FAA has reviewed and approved The Enstrom Helicopter 
Corporation Service Directive Bulletin No. 0083, dated July 16, 1993, 
that describes an initial inspection of the shafts for evidence of 
separation between the composite-wrapping and the shaft, corrosion, or 
cracks. Service Directive Bulletin No. 0083 also specifies replacement 
of certain shafts.
    Since the unsafe condition described is likely to exist or develop 
on other helicopters of the same type design, the FAA issued Priority 
Letter AD 93-15-10 to prevent failure of the shaft, loss of the main 
rotor, and subsequent loss of control of the helicopter. The AD 
requires an initial inspection of the shaft, part number (P/N) 28-
13183, for composite-wrapping separation, red color residue, corrosion, 
or cracks, and replacement of the shaft upon discovery of these 
conditions. The AD also requires replacement of the shaft whenever 
vibrations occur that cannot be corrected with track and balance 
procedures or if track and balance procedures are required more than 
once. Further, the AD requires replacement of any shaft, P/N 28-13183, 
with an airworthy shaft, P/N 28-13140-11 or P/N 28-13104-1, within the 
next 10 hours' time-in-service or at the next annual inspection after 
the effective date of this AD, whichever occurs first. The actions are 
required to be accomplished in accordance with the service directive 
bulletin described previously.
    Since it was found that immediate corrective action was required, 
notice and opportunity for prior public comment thereon were 
impracticable and contrary to the public interest, and good cause 
existed to make the AD effective immediately by individual letters 
issued on August 3, 1993, to all known U.S. owners and operators of The 
Enstrom Helicopter Corporation Model F-28A, F-28C, F-28C2, F-28F, 280, 
280C, 280F, and 280FX helicopters. These conditions still exist, and 
the AD is hereby published in the Federal Register as an amendment to 
Section 39.13 of part 39 of the Federal Aviation Regulations (FAR) to 
make it effective to all persons.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this rule by 
submitting such written data, views, or arguments as they may desire. 
Communications should identify the Rules Docket number and be submitted 
in triplicate to the address specified under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the rule. All comments submitted will be 
available, both before and after the closing date for comments, in the 
Rules Docket for examination by interested persons. A report that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 93-SW-21-AD.'' The postcard will be date stamped and 
returned to the commenter.
    The regulations adopted herein will not have substantial direct 
effects 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. Therefore, in 
accordance with Executive Order 12612, it is determined that this final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If it is 
determined that this emergency regulation otherwise would be 
significant under DOT Regulatory Policies and Procedures, a final 
regulatory evaluation will be prepared and placed in the Rules Docket. 
A copy of it, if filed, may be obtained from the Rules Docket at the 
location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 14 CFR part 
39 of the Federal Aviation Regulations as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [AMENDED]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:


The Enstrom Helicopter Corporation: Amendment 39-8766. Docket Number 
93-SW-21-AD. Final Rule of a Priority Letter AD.

    Applicability: Model F-28A, F-28C, F-28C2, F-28F, 280, 280C, 
280F, and 280FX helicopters equipped with composite-wrapped main 
rotor shaft, part number (P/N) 28-13183, certificated in any 
category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent failure of the main rotor shaft (shaft), loss of the 
main rotor, and subsequent loss of control of the helicopter, 
accomplish the following:
    (a) Before further flight, after the effective date of this 
airworthiness directive (AD), perform a one-time inspection of the 
shaft in accordance with paragraph 5.1 of The Enstrom Helicopter 
Corporation Service Directive Bulletin No. 0083, dated July 16, 
1993.
    (b) If the shaft is found with composite-wrapping separation, 
corrosion, red color residue or cracks during the inspections in 
paragraph (a) of this AD, remove the shaft from further service and 
install an airworthy shaft, P/N 28-13140-11 or P/N 28-13104-1.
    (c) If main rotor (M/R) vibrations occur that cannot be 
corrected with track and balance procedures; or, if M/R track and 
balance procedures are required more than once, replace the shaft 
with an airworthy shaft, P/N 28-13140-11 or P/N 28-13104-1, before 
further flight.
    (d) Within the next 10 hours' time-in-service, or at the next 
annual inspection after the effective date of this AD, whichever 
occurs first, remove the shaft, P/N 28-13183, and install an 
airworthy shaft, P/N 28-13140-11 or P/N 28-13104-1.
    (e) Installation of airworthy shafts, P/N 28-13140-11 or P/N 28-
13104-1, constitutes terminating action for the requirements of this 
AD.
    (f) An alternative method of compliance or adjustment of the 
compliance time, which provides an acceptable level of safety, may 
be used when approved by the Manager, Chicago Aircraft Certification 
Office, 2300 East Devon Avenue, room 232, Des Plaines, IL 60018. 
Operators shall submit their requests through an FAA Principal 
Maintenance Inspector, who may concur or comment and then send it to 
the Manager, Chicago Aircraft Certification Office.

    Note: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Chicago Aircraft Certification Office.

    (g) Special flight permits may be issued in accordance with FAR 
21.197 and 21.199 to operate the helicopter to a location where the 
requirements of only paragraphs (a) and (d) of this AD can be 
accomplished.
    (h) The inspection, removal and replacement shall be done in 
accordance with The Enstrom Helicopter Corporation Service Directive 
Bulletin No. 0083, dated July 16, 1993. This incorporation by 
reference was approved by the Director of the Federal Register in 
accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be 
obtained from The Enstrom Helicopter Corporation, Twin County 
Airport, P.O. Box 490, Menominee, Michigan 49858. Copies may be 
inspected at the FAA, Office of the Assistant Chief Counsel, 2601 
Meacham Boulevard, room 663, Fort Worth, Texas; or at the Office of 
the Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.
    (i) This amendment becomes effective January 28, 1994, to all 
persons except those persons to whom it was made immediately 
effective by Priority Letter AD 93-15-10, issued August 3, 1993, 
which contained the requirements of this amendment.

    Issued in Fort Worth, Texas, on December 3, 1993.
James D. Erickson,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 94-141 Filed 1-12-94; 8:45 am]
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