[Federal Register Volume 64, Number 70 (Tuesday, April 13, 1999)]
[Rules and Regulations]
[Pages 17966-17968]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-9131]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 99-SW-24-AD; Amendment 39-11126; AD 99-07-17]
RIN 2120-AA64
Airworthiness Directives; Robinson Helicopter Company Model R22
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) 99-07-17 which was sent
previously to all known U.S. owners and operators of Robinson
Helicopter Company (RHC) Model R22 helicopters by individual letters.
This AD requires, before further flight, inserting a Special Pilot
Caution into the Normal Procedures section of the Rotorcraft Flight
Manual (RFM). This amendment is prompted by several reports of sprag
clutch assemblies with cracked or fractured sprag ends. The sprag
clutch failures, determined to be due to a change in the manufacturing
process, could result in loss of main rotor revolutions-per-minute
(RPM) during autorotations. The intent of this AD is to alert pilots of
the potential for the sprag clutch failing to overrun during
autorotation, loss of main rotor RPM, and subsequent loss of control of
the helicopter.
DATES: Effective April 28, 1999, to all persons except those persons to
whom it was made immediately effective by Priority Letter AD 99-07-17,
issued on March 26, 1999, which contained the requirements of this
amendment.
Comments for inclusion in the Rules Docket must be received on or
before June 14, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Office of the Regional Counsel, Southwest Region,
Attention: Rules Docket No. 99-SW-24-AD, 2601 Meacham Blvd., Room 663,
Fort Worth, Texas 76137.
FOR FURTHER INFORMATION CONTACT: 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: On March 26, 1999, the FAA issued Priority
Letter AD 99-07-17, applicable to RHC Model R22 helicopters, which
requires, before further flight, inserting a Special Pilot Caution into
the Normal Procedures section of the RFM. That action was prompted by
several reports of sprag clutch assemblies, including one from wreckage
of an accident that occurred within the past year, with cracked or
fractured sprag ends. The sprag clutch failures, determined to be due
to a change in the manufacturing process, could result in loss of main
rotor RPM during autorotations. The intent of that priority letter AD
is to alert pilots of the potential for the sprag clutch failing to
overrun during autorotation, loss of main rotor RPM, and subsequent
loss of control of the helicopter.
The FAA has reviewed Robinson Helicopter Company R22 Service
Bulletin SB-85, dated March 22, 1999, which describes procedures for
checking whether sprag clutches with certain serial numbers are
installed and replacing certain serial numbered sprag clutches, and
inserting a Special Pilot Caution in the Normal Procedures section of
the RFM.
Since the unsafe condition described is likely to exist or develop
on other RHC Model R22 helicopters of the same type design, the FAA
issued Priority Letter AD 99-07-17 to alert pilots of the potential for
the sprag clutch failing to overrun during autorotation due to the
failure of the sprags within the sprag clutch assembly, and loss of
main rotor RPM. The AD requires, before further flight, inserting a
Special Pilot Caution into the Normal Procedures section of the RFM
which primarily addresses autorotation maneuvers and a before every
flight sprag clutch (split tach needles) check for proper function of
the sprag clutch. Inserting the Special Pilot caution is an interim
action. The FAA will issue an AD to supersede this AD and require
replacing the clutch assembly when parts become available from the
manufacturer. The short compliance time involved is required because
the previously described critical unsafe condition can adversely affect
the structural integrity of the helicopter. Therefore, inserting a
Special Pilot Caution into the Normal Procedures section of the RFM is
required before further flight, and this AD must be issued immediately.
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 March 26, 1999, to all
[[Page 17967]]
known U.S. owners and operators of RHC Model R22 helicopters. These
conditions still exist, and the AD is hereby published in the Federal
Register as an amendment to section 39.13 of the Federal Aviation
Regulations (14 CFR 39.13) to make it effective to all persons.
The FAA estimates that 880 helicopters of U.S. registry will be
affected by this AD, that it will take approximately 0.5 work hour per
helicopter to insert the caution into the RFM, and that the average
labor rate is $60 per work hour. Based on these figures, the total cost
impact of the AD on U.S. operators is estimated to be $26,400.
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 No. 99-SW-24-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, 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 adding a new airworthiness directive
to read as follows:
AD 99-07-17 Robinson Helicopter Company: Amendment 39-11126. Docket
No. 99-SW-24-AD.
Applicability: Model R22 helicopters, serial numbers (S/N) 0002
through 2862, with sprag clutch, part number (P/N)
A188-2, S/N's 3708 through 3757, 3808 through 3893, and 3908 through
4207, installed, certificated in any category.
Note 1: This AD applies to each helicopter identified in the
preceding applicability provision, regardless of whether it has been
otherwise 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 request approval for an
alternative method of compliance in accordance with paragraph (b) of
this AD. The request should include an assessment of the effect of
the modification, alteration, or repair on the unsafe condition
addressed by this AD; and, if the unsafe condition has not been
eliminated, the request should include specific proposed actions to
address it.
Compliance: Required before further flight, unless accomplished
previously.
To alert pilots of the potential for the sprag clutch failing to
overrun during autorotation due to failure of the sprags within the
sprag clutch assembly, and loss of main rotor revolutions-per-
minute, accomplish the following:
(a) Insert either the Special Pilot Caution, revised March 22,
1999, which is contained in Robinson Helicopter Company R22 Service
Bulletin SB-85, dated March 22, 1999, or the following Special Pilot
Caution paragraphs, into the Normal Procedures section of the
Rotorcraft Flight Manual, between pages P.4-8 and P.4-9:
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SPECIAL PILOT CAUTION
Some sprags in overrunning clutches have been found cracked in service.
A broken sprag could conceivably prevent the clutch from overrunning
when entering autorotation. Until the clutch in this aircraft has been
replaced, do not enter practice autorotations by rapidly closing or
``chopping'' the throttle. ``Chopping'' the throttle could result in a
sudden loss of rotor RPM if the clutch failed to disengage.
Enter autorotation by first lowering collective and then rolling off
just enough throttle to produce a small visible split between the rotor
and engine tachometer needles. If the clutch fails to disengage,
immediately complete a power recovery. Perform hovering autos only
after checking the function of the overrunning sprag clutch prior to
lift-off, then smoothly rolling off the throttle from a low hover with
the skids no more than two feet above the ground.
Be sure to perform the sprag clutch check (split tach needles) before
every flight, not just the first flight of the day.
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[[Page 17968]]
(b) 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.
(c) 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.
(d) This amendment becomes effective on April 28, 1999 to all
persons except those persons to whom it was made immediately
effective by Priority Letter AD 99-07-17, issued March 26, 1999,
which contained the requirements of this amendment.
Issued in Fort Worth, Texas, on April 5, 1999.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 99-9131 Filed 4-12-99; 8:45 am]
BILLING CODE 4910-13-U