[Federal Register Volume 61, Number 56 (Thursday, March 21, 1996)]
[Rules and Regulations]
[Pages 11536-11538]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-6420]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 93-SW-26-AD; Amendment 39-9539; AD 96-06-02]


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to The Enstrom Helicopter Corporation Model (Enstrom) 
F-28A, F-28C, 280, and 280C 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 amendment requires that the 
visual inspections apply to both the upper and lower swashplate 
bearings (bearings); expands the applicability to include the Model F-
28C-2 helicopter; limits the applicability to those affected 
helicopters manufactured prior to January 1, 1981; establishes a 
retirement life of 1,200 hours time-in-service for certain bearings; 
and provides a corrected upper swashplate bearing part number. This 
amendment is prompted by the necessity to require visual inspections of 
the lower swashplate bearings; to expand the applicability to include 
the Model F-28C-2 helicopter; to establish a retirement life for 
certain bearings; and to correct the upper swashplate bearing part 
number from the existing AD. The actions specified by this AD are 
intended to prevent failure of the bearings and subsequent loss of 
control of the helicopter.

DATES: Effective April 25, 1996.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of April 25, 1996.

ADDRESSES: 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 
Meacham Blvd., 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, 
Airframe Branch, Chicago Aircraft Certification Office, Small Airplane 
Directorate, FAA, 2300 East Devon Avenue, Room 232, Des Plaines, 
Illinois 60018, telephone (708) 294-7136, fax (708) 294-7834.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) by superseding AD 76-06-11, 
Amendment 39-2560, (41 FR 13906, April 1, 1976), which is applicable to 
Enstrom Model F-28A, F-28C, 280, and 280C helicopters manufactured 
prior to January 1, 1981, was published in the Federal Register on July 
6, 1994 (59 FR 34584). That action proposed to require visual 
inspections of both the upper and lower swashplate bearings; to expand 
the applicability to include the Model F-28C-2 helicopter which was 
omitted in AD 76-06-11; to establish a retirement life of 1,200 hours 
time-in-service for certain upper and lower swashplate bearings; and to 
correct the upper swashplate bearing part number in the existing AD. 
That action also proposed an optional terminating action from the 
requirements of the AD and

[[Page 11537]]
limited the applicability of the AD requirements to those affected 
model helicopters manufactured prior to January 1, 1981.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. No comments were received on the 
proposal or the FAA's determination of the cost to the public. The FAA 
has determined that air safety and the public interest require the 
adoption of the rule as proposed except for editorial changes and 
adding explanatory Note 1, relating to the scope of the applicability 
statement when modifications, alterations, or repairs have been made in 
the area subject to the requirements of the AD. Additionally, the FAA 
has revised the proposed estimated average labor rate from $55 per work 
hour to an estimated average labor rate of $60 per work hour in the 
preamble portion of this final rule. This revision will increase the 
estimated total cost impact of the AD from $1,105,500 to $1,122,000. 
The FAA has determined that these changes will neither increase the 
economic burden on any operator nor increase the scope of the AD.
    The FAA estimates that 660 helicopters of U.S. registry will be 
affected by this AD, that it will take approximately 5 work hours per 
helicopter to accomplish the required actions, and that the average 
labor rate is $60 per work hour. Required parts will cost approximately 
$1,400 per helicopter. Based on these figures, the total cost impact of 
the AD on U.S. operators is estimated to be $1,122,000.
    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.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it 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 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. 106(g), 40113, 44701.


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), Amendment 39-9539, to read as follows:

[AD 96-06-02] The Enstrom Helicopter Corporation: Amendment 39-9539. 
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.

    Note 1: This AD applies to each helicopter identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For helicopters that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must use the authority 
provided in paragraph (e) to request approval from the FAA. This 
approval may address either no action, if the current configuration 
eliminates the unsafe condition, or different actions necessary to 
address the unsafe condition described in this AD. Such a request 
should include an assessment of the effect of the changed 
configuration on the unsafe condition addressed by this AD. In no 
case does the presence of any modification, alteration, or repair 
remove any helicopter from the applicability of this AD.

    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, part number (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 seals from the upper and lower 
swashplate bearings 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 the bearing seals 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) Installation of 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, 
constitutes 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 2: 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 
sections 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.
    (g) The optional replacement permitted by paragraph (d) shall be 
done in accordance with The Enstrom Helicopter Corporation Service 
Information Letter No. 0110, Revision B, dated March 18, 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 Blvd., Room 663, Fort Worth, Texas; or at the Office of 
the Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.

[[Page 11538]]

    (h) This amendment becomes effective on April 25, 1996.

    Issued in Fort Worth, Texas, on March 11, 1996.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 96-6420 Filed 3-20-96; 8:45 am]
BILLING CODE 4910-13-U