[Federal Register Volume 59, Number 128 (Wednesday, July 6, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-16273]


[[Page Unknown]]

[Federal Register: July 6, 1994]


                                                   VOL. 59, NO. 128

                                            Wednesday, July 6, 1994

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 93-SW-26-AD]

 

Airworthiness Directives; The Enstrom Helicopter Corporation 
Model F-28A, F-28C, F-28C-2, 280, and 280C Series Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to The Endstrom Helicopter 
Corporation Model F-28A, F-28C, 280, and 280C series helicopters, that 
currently requires an initial and repetitive visual inspections of the 
upper swashplate bearings for corrosion, and replacement of defective 
upper swashplate bearings with airworthy bearings. This action would 
require that the visual inspections apply to both the upper and lower 
swashplate bearings (bearings); expand the applicability to those 
affected helicopters manufactured prior to January 1, 1981; establish a 
retirement life of 1,200 hours' time-in-service for certain bearings; 
and provide a corrected upper swashplate bearing part number. This 
proposal is prompted by the necessity to require visual inspection so 
the lower swashplate bearings; expand the applicability to include the 
Model F-28C-2 helicopter; establish a retirement life for certain 
bearings; and correct the upper swashplate bearing part number from the 
existing AD. The actions specified by the proposed AD are intended to 
prevent failure of the bearings and subsequent loss of control of the 
helicopter.

DATES: Comments must be received by September 6, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Assistant Chief Counsel, Attention: 
Rules Docket No. 93-SW-26-Ad, 2601 Meacham Blvd., Room 663, Fort Worth, 
Texas 76137. Comments may be inspected at this location between 9:00 
a.m. and 3:00 p.m., Monday through Friday, except Federal holidays.
    The service information referenced in the proposed rule 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 
Meachum Blvd., Room 663, Fort Worth, Texas.

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

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed 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 above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 93-SW-26-Ad.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Office of the Assistant Chief Counsel, Attention: Rules 
Docket No. 93-SW-26-Ad, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 
76137.

Discussion

    On March 19, 1976, the FAA issued AD 76-01-11, Amendment 39-2560, 
(41 FR 13906, April 1, 1976), to require an initial and repetitive 
visual inspection of the upper swashplate bearing, part number (P/N) 
Z993L13XR3B, for corrosion, and replacement of corroded upper 
swashplate bearings. That action was prompted by three reports of upper 
swashplate bearing failures that were attributed to corrosion. These 
failures occurred between 205 and 586 hours' time-in-service (TIS). In 
two of these incidents, the probable cause of the upper swashplate 
bearing failures was corrosion of the balls and race due to water 
impregnating the housing after the loss of lubricant. This led to a 
spalling interaction between the balls and race, resulting in upper 
swashplate bearing failure. After reviewing the data, the FAA has 
determined that corrosion of either upper or lower bearings (bearings) 
could create an unsafe condition. These conditions, if not corrected, 
could result in failure of the bearings and subsequent loss of control 
of the helicopter.
    Since the issuance of that AD, improved and modified bearings have 
been approved by the FAA for these model helicopters. Additionally, the 
manufacturer has issued The Enstrom Helicopter Corporation Service 
Information Letter (SIL) No. 0110, Revision B, dated March 18, 1993, 
that extends the previous visual inspections to include the Model F-
28C-2 helicopters. The SIL describes an approved swashplate 
modification and indicates that the SIL should only apply to those 
affected helicopters manufactured prior to January 1, 1981. In 
addition, a swashplate modification that would constitute terminating 
action for the requirements of this AD has been approved.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would supersede AD 76-06-11 to require visual inspections 
of the lower swashplate bearings; expand the applicability to the Model 
F-28C-2 helicopter; establish a retirement life of 1,200 hours' time-
in-service for certain upper and lower swashplate bearings; and correct 
the upper swashplate bearing part number in the existing AD. This 
proposed AD would also provide an optional terminating action from the 
requirements of this AD and limit the applicability of the AD 
requirements to those affected model helicopters manufactured prior to 
January 1, 1981.
    The FAA estimates that 660 helicopters of U.S. registry would be 
affected by this proposed AD, that it would take approximately 5 work 
hours per helicopter to accomplish the proposed actions, and that the 
average labor rate is $55 per work hour. Required parts would cost 
approximately $1,400 per helicopter. Based on these figures, the total 
cost impact of the proposed AD on U.S. operators is estimated to be 
$1,105,500.
    The regulations proposed herein would 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 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that 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); 
and (3) if promulgated, 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. A copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
part 39 of the Federal Aviation Regulations (14 CFR part 39) 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 removing amendment 39-2560 (41 FR 
13906, April 1, 1976), and by adding a new airworthiness directive 
(AD), to read as follows:

The Enstrom Helicopter Corporation: Docket No. 93-SW-26-AD. 
Supersedes AD 76-06-11, Amendment 39-2560.

    Applicability: Model F-28A, F-28C, F-28C-2, 280, and 280C 
helicopters, manufactured prior to January 1, 1981, certificated in 
any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent failure of the upper and lower swashplate bearings 
(bearings) and subsequent loss of control of the helicopter, 
accomplish the following:
    (a) Within the next 10 hours' time-in-service (TIS) after the 
effective date of this AD, and thereafter at intervals not to exceed 
100 hours' TIS since the last inspection, perform a visual 
inspection of the upper swashplate bearing, P/N Z993L13X3B, bearing 
number SKF 6013-RS, or ECD013-13, and lower swashplate bearing, P/N 
5201SBKZZ-ABEC, or ECD009-11, for corrosion as follows:
    (1) Lower the swashplate to lowest position with the collective 
control.
    (2) Remove the plastic bearing seal using a blunt scribe.
    (3) Using an inspection mirror, visually inspect the bearings 
for grease lubricant and any evidence of corrosion. Rotate the 
bearings and housing to reposition balls and race for complete 
inspection. For bearings found free of corrosion or defects, repack 
them with Exxon ANDOK-B grease or any MIL-G-18709A grease, and 
reinstall them in accordance with the applicable maintenance manual.
    (b) Replace any unairworthy bearing with an airworthy bearing in 
accordance with the applicable maintenance manual.
    (c) Before further flight, after the effective date of this AD, 
remove all upper and lower swashplate bearings having 1,200 hours' 
or more TIS, and replace them with airworthy bearings. For bearings 
with less than 1,200 hours' TIS on the effective date of this AD, 
replace the bearings on or before attaining 1,200 hours' TIS.
    (d) The owner may elect to install revised upper swashplate 
bearing housing, P/N 28-16108-2, and lower swashplate bearing 
housing, P/N 28-16361-1, that are equipped with grease fittings and 
integral bearing shields as described in The Enstrom Helicopter 
Corporation Service Information Letter No. 0110, Revision B, dated 
March 18, 1993. This would constitute terminating action for the 
requirements of this AD.
    (e) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used when approved by the Manager, Chicago Aircraft Certification 
Office, FAA. 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.

    (f) Special flight permits may be issued in accordance with 
Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 
21.197 and 21.199) to operate the helicopter to a location where the 
requirements of this AD can be accomplished.

    Issued in Fort Worth, Texas, on June 27, 1994.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 94-16273 Filed 7-5-94; 8:45 am]
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