[Federal Register Volume 61, Number 54 (Tuesday, March 19, 1996)]
[Rules and Regulations]
[Pages 11129-11131]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-6421]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 93-SW-27-AD; Amendment 39-9540; AD 96-06-03]
Airworthiness Directives; The Enstrom Helicopter Corporation
Model F-28, F-28A, F-28C, F-28C-2, F-28F, 280, 280C, 280F, and 280FX
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 (Enstrom) Model
F-28, F-28A, F-28C, F-28C-2, F-28F, 280, 280C, 280F, and 280FX
helicopters, that currently requires initial and repetitive inspections
of a certain main rotor transmission clutch assembly (clutch assembly)
for bearing roughness, noise, lock-up, or improper oil level and, if
necessary, replacement of the clutch assembly. The existing AD also
requires replacement of the clutch assembly at certain time-in-service
intervals. This amendment requires the same inspections and
replacements as required by the existing AD, but would provide for
installation of an additional approved replacement part number and
provide a reference to three additional manufacturer service documents.
This amendment is prompted by the approval of an additional replacement
clutch assembly; the manufacturer's issuance of additional service
information, and the need to correct a service information letter's
number. The actions specified by this AD are intended to prevent
failure of the clutch assembly, loss of control of the main rotor
system, and subsequent loss of control of the helicopter.
EFFECTIVE DATE: April 23, 1996.
ADDRESSES: The service information referenced in this AD 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.
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 (847) 294-7136, fax (847) 294-7834.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) by superseding AD 89-04-09,
Amendment 39-6138 (54 FR 6391, February 10, 1989), which is applicable
to Enstrom Model F-28, F-28A, F-28C, F-28C-2, F-28F, 280, 280C, 280F,
and 280FX helicopters, was published in the Federal Register on
September 13, 1994 (59 FR 46944). That action proposed to require
initial and repetitive inspections of certain clutch assemblies for
bearing roughness, noise, lock-up, or improper oil levels and, if
necessary, immediate replacement of the clutch assembly. Owner/operator
checks were proposed after engine start and rotor engagement to verify
proper operation of the clutch assembly, and after each engine
shutdown, while the main rotor is still turning down, to check for
abnormal noise (such as a clicking or racheting sound) from the upper
pulley that houses the clutch assembly. Those proposed owner/operator
checks do not require the use of tools, precision measuring equipment,
training, pilot logbook endorsements, or the use of technical data not
contained in the AD. Additionally, those owner/operator checks are
considered part of the normal pilot ``Before Takeoff'' and ``After
Landing'' checks and were allowed by the existing AD. Those owner/
operator checks are additional measures to ensure, between 25 hours TIS
inspections, that sufficient lubricants are maintained in the clutch
assembly and not lost through a leaking seal. Those checks may be
performed by an owner/operator holding at least a private pilot
certificate and must be entered into the aircraft records showing
compliance with this AD in accordance with sections 43.11 and
91.417(a)(2)(v) of the Federal Aviation Regulations. The action also
proposed to require replacement of the clutch assembly at certain TIS
intervals.
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 revising
paragraph (a)(3) of the AD to clarify the aircraft records entries, 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 $471,420 to $473,040 if only
overhauled clutch assemblies are installed, and from $1,718,820 to
$1,720,440 if only zero-time clutch assemblies are used. 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 162 helicopters of U.S. registry will be
affected by this AD, that it will take approximately 2 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
$2,800 to overhaul or $10,500 for a zero-time clutch assembly per
helicopter. Based on these figures, the total cost impact of the AD on
U.S. operators is estimated to be from $473,040 if only overhauled
clutch assemblies are installed, to $1,720,440 if only zero-time clutch
assemblies are installed.
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, 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
[[Page 11131]]
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 USC 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by removing Amendment 39-6138 (54 FR
6391, February 10, 1989), and by adding a new airworthiness directive
(AD), Amendment 39-9540, to read as follows:
AD 96-06-03 The Enstrom Helicopter Corporation: Amendment 39-9540.
Docket No. 93-SW-27-AD. Supersedes AD 89-04-09, Amendment 39-6138.
Applicability: Model F-28, F-28A, F-28C, F-28C-2, F-28F, 280,
280C, 280F, and 280FX helicopters, 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 main rotor transmission clutch
assembly (clutch assembly), loss of control of the main rotor
system, and subsequent loss of control of the helicopter accomplish
the following:
(a) For Model F-28, F-28A, F-28C, F-28C-2, 280, and 280C
helicopters, with clutch assembly part number (P/N) 28-13401-1
(Formsprag CL 40526-1 through -7) installed, perform the following:
(1) Before the first flight of each day, before takeoff, gently
close the throttle, splitting the tachometer needles to verify
proper operation of the clutch assembly. If the tachometer needles
do not split, before further flight, inspect the clutch assembly in
accordance with paragraph (a)(4).
(2) At the conclusion of the last flight of each day, after
engine shutdown, while the main rotor is still running down, listen
for any abnormal noise (such as a clicking or racheting sound) from
the area of the upper pulley that houses the clutch assembly. If any
abnormal noise is heard from the clutch assembly, inspect the clutch
assembly in accordance with paragraph (a)(4).
(3) The operational checks required by paragraphs (a)(1) and
(a)(2) may be performed by an owner/operator holding at least a
private pilot certificate and must be entered into the aircraft
records showing compliance with paragraphs (a)(1) and (a)(2) of this
AD in accordance with 14 CFR 43.11 and 91.417(a)(2)(v).
(4) If any irregularities are noted while performing the
procedures required by paragraph (1) or (2), inspect the clutch
assembly to determine if it is locked-up, or if the upper pulley
will rotate. Rotate it in both directions while feeling for any
bearing roughness and listening for any bearing noise. The upper
pulley should free-wheel if rotated in a clockwise direction and
engage if rotated in a counterclockwise direction.
(5) Within the next 25 hours time-in-service (TIS) after the
effective date of this airworthiness directive (AD), make an entry
in the aircraft log book documenting the clutch assembly part
number, the number of hours TIS, and the date.
(6) Within the next 25 hours TIS after the effective date of
this AD, and thereafter at intervals not to exceed 100 hours TIS,
inspect the clutch assembly for proper oil level in accordance with
the appropriate maintenance manual. If there has been less than a
complete loss of oil, replenish the oil and service the clutch
assembly in accordance with the applicable maintenance manual.
Note 2: The Enstrom Helicopter Corporation (Enstrom) Service
Information Letter No. 0079A, dated February 14, 1980, provides
specific information regarding clutch lubrication.
(7) If there has been a complete oil loss, or lock-up, noise, or
roughness are detected from the clutch assembly as a result of the
inspections required by paragraphs (a) (4) or (a) (6) of this AD,
before further flight, replace the clutch assembly, P/N 28-13401-1
(Formsprag CL 40526-1 through -7), with an airworthy clutch
assembly, P/N 28-13401-2 (Formsprag CL 40526-8) or P/N 28-13401-4
(Formsprag CL 40526-10).
(8) For a clutch assembly, P/N 28-13401-1 (Formsprag CL 40526-1
through -7), that has 1,175 or more hours TIS on the effective date
of this AD, within the next 25 hours TIS, replace the clutch
assembly with an airworthy clutch assembly, P/N 28-13401-2
(Formsprag CL 40526-8) or P/N 28-13401-4 (Formsprag CL 40526-10).
(9) For a clutch assembly, P/N 28-13401-1 (Formsprag CL 40526-1
through-7), that has less than 1,175 hours TIS on the effective date
of this AD, replace the clutch assembly with an airworthy clutch
assembly, P/N 28-13401-2 (Formsprag CL 40526-8) or P/N 28-13401-4
(Formsprag CL 40526-10), prior to the clutch assembly accumulating
1,200 hours TIS.
Note 3: The clutch service information published in The Enstrom
Helicopter Corporation (Enstrom) Service Note No. 0027, dated
December 9, 1975; Enstrom Service Information Letter No. 0084, dated
December 19, 1978; Enstrom Service Information Letter No. 0079A,
dated February 14, 1980; Service Information Letter No. 0088,
Revision A, dated August 6, 1980, Enstrom Service Directive Bulletin
No. 0068, Revision A, dated July 9, 1990; and Enstrom Service
Directive Bulletin No. 0069, Revision A, dated July 9, 1990;
pertains to this AD.
(b) For Model F-28F, 280F, and 280FX helicopters, accomplish the
following:
(1) Within the next 25 hours TIS after the effective date of
this AD, determine the part number of the clutch assembly.
(2) If a clutch assembly, P/N 28-13401-1 (Formsprag CL 40526-1
through -7), is found, before further flight, replace it with an
airworthy clutch assembly, P/N 28-13401-2 (Formsprag CL 40526-8) or
P/N 28-13401-4 (Formsprag CL 40526-10). The clutch assembly, P/N 28-
13401-1 (Formsprag CL 40526-1 through -7), is not approved for use
on Enstrom Model F-28F, 280F, or 280FX helicopters.
(c) Installation of a clutch assembly, P/N 28-13401-2 (Formsprag
CL 40526-8) or P/N 28-13401-4 (Formsprag CL 40526-10), on Model F-
28, F-28A, F-28C, F-28C-2, F-28F, 280, 280C, 280F, and 280FX
helicopters constitutes a terminating action for the requirements of
this AD.
(d) This AD establishes a retirement life of 1,200 hours TIS for
the clutch assembly, P/N 28-13401-1 (Formsprag CL 40526-1 through -
7). However, for clutch assemblies with 1,175 or more hours TIS on
the effective date of this AD, those clutch assemblies need not be
retired until on or before the accumulation of an additional 25
hours TIS.
(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 4: 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) This amendment becomes effective on April 23, 1996.
Issued in Fort Worth, Texas, on March 11, 1996.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 96-6421 Filed 3-18-96; 8:45 am]
BILLING CODE 4910-13-U