[Federal Register Volume 62, Number 148 (Friday, August 1, 1997)]
[Rules and Regulations]
[Pages 41260-41262]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-20195]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-SW-19-AD; Amendment 39-10092; AD 97-16-02]
RIN 2120-AA64
Airworthiness Directives; Robinson Helicopter Company Model R44
Helicopters
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
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SUMMARY: This amendment adopts a new airworthiness directive (AD) that
is applicable to Robinson Helicopter Company (Robinson) Model R44
helicopters. This action requires inspections of the belt tension
actuator switches (up-limit switches) for proper
[[Page 41261]]
operation, and replacement if necessary; and replacement of a certain
part-numbered clutch assembly. This amendment is prompted by six
occurrences of prematurely worn sprag clutches. The actions specified
in this AD are intended to prevent failure of the sprag clutch to lock
in the driving direction, which would result in loss of power to the
main rotor system and a subsequent forced landing; or failure of the
sprag clutch to unlock in the overrunning direction, which, if combined
with engine failure, would result in an inability to autorotate and a
subsequent loss of control of the helicopter.
DATES: Effective August 18, 1997.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of August 18, 1997.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of August 18, 1997.
Comments for inclusion in the Rules Docket must be received on or
before September 30, 1997.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Office of the Assistant Chief Counsel, Attention:
Rules Docket No. 97-SW-19-AD, 2601 Meacham Blvd., Room 663, Fort Worth,
Texas 76137.
The service information referenced in this AD may be obtained from
Robinson Helicopter Company, 2901 Airport Drive, Torrance, California
90505, telephone (310) 539-0508, fax (310) 539-5198. This information
may be examined at the FAA, Office of the Assistant Chief Counsel, 2601
Meacham Blvd., Room 663, Fort Worth, Texas 76137; or at the Office of
the Federal Register, 800 North Capitol Street, NW., suite 700,
Washington, DC.
FOR FURTHER INFORMATION CONTACT: Ms. Elizabeth Bumann, Aerospace
Engineer, FAA, Los Angeles Aircraft Certification Office, Propulsion
Branch, 3960 Paramount Blvd., Lakewood, California 90712, telephone
(562) 627-5265, fax (562) 627-5210.
SUPPLEMENTARY INFORMATION: This amendment adopts a new Airworthiness
Directive (AD), which is applicable to Robinson Model R44 helicopters
and requires, within 25 hours time-in-service (TIS) after the effective
date of this AD and thereafter at intervals not to exceed 100 hours
TIS, an inspection of both up-limit switches, part number (P/N) V3-
1001, for proper operation, and replacement of either switch, if
necessary. Additionally, this AD requires, within 50 hours TIS after
the effective date of this AD, replacement of the clutch assembly, P/N
C018-1, with clutch assembly, P/N C018-2 or P/N C018-2A. This AD is
prompted by six occurrences of prematurely worn sprag clutches. Five of
those clutch assemblies' hours TIS ranged from 286.3 to 828.6 hours
TIS. All of the clutch assemblies were making noise during the landings
and/or shutdowns. One clutch assembly would not allow the main rotor to
disengage from the engine during a practice autorotation. Excessive
wear of the sprag crowns and chattering of the sprag races causes
erratic operation of the clutch by preventing the sprags from rolling
into or releasing from the locked position. A latent failure of one up-
limit switch can exist undetected, eliminating the redundancy of the
system. A failure of both up-limit switches while in the closed
position will result in over-tensioning of the drive belts. The actions
specified in this AD are intended to prevent failure of the sprag
clutch to lock in the driving direction, which would result in loss of
power to the main rotor system and a subsequent forced landing; or
failure of the sprag clutch to unlock in the overrunning direction,
which, if combined with engine failure, would result in an inability to
autorotate and a subsequent loss of control of the helicopter.
The FAA has reviewed Robinson Helicopter Company R44 Service
Bulletin SB-21, dated April 18, 1997, which describes procedures for
removing the aft engine cowling and inspecting to verify that both up-
limit switches function properly. If either up-limit switch does not
function properly, the service bulletin refers the reader to the
replacement procedures in the maintenance manual. The FAA has also
reviewed Robinson Helicopter Company R44 Service Bulletin SB-23, dated
May 30, 1997, which describes or refers to the appropriate procedures
for replacing clutch assembly, P/N C018-1. The compliance times of this
AD differ from those stated in the service bulletins. Robinson
Helicopter Company R44 Service Bulletin SB-21 describes a one-time
inspection within the next 10 hours TIS, or by April 30, 1997,
whichever occurs first; this AD requires an initial inspection within
25 hours TIS after the effective date of this AD, and thereafter,
repetitive inspections at intervals not to exceed 100 hours TIS.
Robinson Helicopter Company R44 Service Bulletin SB-23 describes
replacing the clutch assembly within the next 100 hours TIS, or by
September 30, 1997, whichever occurs first; this AD requires replacing
the clutch assembly within 50 hours TIS after the effective date of
this AD, since the only indication of excessive sprag clutch wear is
hard or rough engagement of the clutch, which may be difficult for a
pilot to detect. The failure of the clutch assembly to allow the main
rotor system to disengage from the engine in the event of an engine
failure creates a significant unsafe condition in that this condition
would result in an inability to autorotate.
Since an unsafe condition has been identified that is likely to
exist or develop on other Robinson Model R44 helicopters of the same
type design, this AD is being issued to prevent failure of the sprag
clutch to lock in the driving direction, which will result in loss of
power to the main rotor and a subsequent forced landing; or failure of
the sprag clutch to unlock in the overrunning direction, which, if
combined with engine failure, could result in catastrophic loss of the
helicopter since the main rotor cannot be disengaged from the engine
for autorotation.
This AD requires both initial and repetitive inspections of the up-
limit switches, P/N V3-1001, to determine that they are functioning
properly, and replacement of either up-limit switch, if necessary; and
replacement of the clutch assembly, P/N C018-1 with clutch assembly, P/
N C018-2 or P/N C018-2A. The actions are required to be accomplished in
accordance with the compliance procedures contained in the service
bulletins described previously.
Since a situation exists that requires the immediate adoption of
this regulation, it is found that notice and opportunity for prior
public comment hereon are impracticable, and that good cause exists for
making this amendment effective in less than 30 days.
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
[[Page 41262]]
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 No. 97-SW-19-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.
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 adding a new airworthiness directive
to read as follows:
97-16-02 Robinson Helicopter Company: Amendment 39-10092. Docket
No. 97-SW-19-AD.
Applicability: Model R44 helicopters, serial numbers 0001
through 0332, 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 (d) 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 sprag clutch to lock in the driving
direction, which would result in loss of power to the main rotor
system and a subsequent forced landing; or failure of the sprag
clutch to unlock in the overrunning direction, which, if combined
with engine failure, would result in an inability to autorotate and
a subsequent loss of control of the helicopter, accomplish the
following:
(a) Within 25 hours time-in-service (TIS) after the effective
date of this AD, and thereafter, at intervals not to exceed 100
hours TIS, inspect both up-limit switches, part number (P/N) V3-
1001, for proper operation in accordance with the Compliance
Procedure in Robinson Helicopter Company R44 Service Bulletin SB-21,
dated April 18, 1997. If the motor runs when the springs are
depressed on one side, the switch on the OPPOSITE side is not
functioning properly.
(b) If the inspections required by paragraph (a) of this AD
indicate that either up-limit switch does not function properly,
replace the up-limit switch with an airworthy up-limit switch in
accordance with the Compliance Procedure contained in Robinson
Helicopter Company R44 Service Bulletin SB-21, dated April 18, 1997.
(c) Within 50 hours TIS after the effective date of this AD,
replace the clutch assembly, P/N C018-1, with a clutch assembly, P/N
C018-2 or P/N C018-2A, in accordance with the Compliance Procedure
contained in Robinson Helicopter Company R44 Service Bulletin SB-23,
dated May 30, 1997.
(d) An alternative method of compliance or adjustment of the
compliance time that provides an acceptable level of safety may be
used if approved by the Manager, Los Angeles 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, Los Angeles 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 Los Angeles Aircraft Certification Office.
(e) 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.
(f) The inspections and replacements, if necessary, shall be
done in accordance with Robinson Helicopter Company R44 Service
Bulletin SB-21, dated April 18, 1997, and Robinson Helicopter
Company R-44 Service Bulletin SB-23, dated May 30, 1997. 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 Robinson Helicopter Company, 2901
Airport Drive, Torrance, California 90505, telephone (310) 539-0508,
fax (310) 539-5198. 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.
(g) This amendment becomes effective on August 18, 1997.
Issued in Fort Worth, Texas, on July 22, 1997.
Mark R. Schilling,
Acting Manager, Rotercraft Directorate, Aircraft Certification Service.
[FR Doc. 97-20195 Filed 7-31-97; 8:45 am]
BILLING CODE 4910-13-U
