[Federal Register Volume 63, Number 217 (Tuesday, November 10, 1998)]
[Rules and Regulations]
[Pages 62931-62935]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-30046]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-SW-56-AD; Amendment 39-10874; AD 98-22-16]
Airworthiness Directives; Robinson Helicopter Company (RHC) Model
R44 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) 98-22-16 which was sent
previously to all known U.S. owners and operators of RHC Model R44
helicopters by individual letters. This amendment supersedes AD 98-12-
19, issued August 5, 1998, applicable to RHC Model R44 helicopters,
that currently requires main rotor blade inspections and replacement if
a crack is found. This amendment requires the same inspections as AD
98-12-19, but mandates replacement of all the affected main rotor
blades prior to further flight after November 15, 1998. This amendment
is prompted by an incident in which a crack was discovered in a main
rotor blade. The actions specified by this AD are intended to prevent
failure of a main rotor blade and subsequent loss of control of the
helicopter.
DATES: Effective November 10, 1998, to all persons except those persons
to whom it was made immediately effective by priority letter AD 98-22-
16, issued on October 22, 1998, which contained the requirements of
this amendment.
Comments for inclusion in the Rules Docket must be received on or
before January 11, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Office of the Regional Counsel, Southwest Region,
Attention: Rules Docket No. 98-SW-56-AD, 2601 Meacham Blvd., Room 663,
Fort Worth, Texas 76137.
FOR FURTHER INFORMATION CONTACT: Frederick Guerin, Aerospace Engineer,
FAA, Los Angeles Aircraft Certification Office, Airframe Branch, 3960
Paramount Blvd., Lakewood, California 90712, telephone (562) 627-5232,
fax (562) 627-5210.
SUPPLEMENTARY INFORMATION: On October 22, 1998, the FAA issued priority
letter AD 98-22-16, applicable to RHC Model R44 helicopters, which
[[Page 62932]]
requires inspecting each main rotor blade for cracks every 5 hours
time-in-service (TIS) until each main rotor blade is replaced with a
redesigned main rotor blade. The main rotor blade must be replaced
prior to further flight after November 15, 1998. The AD was prompted by
an incident in which a pilot heard a loud noise and felt severe
vibrations while hovering, resulting in a forced landing. Upon
inspection, a crack was found in a main rotor blade. The crack started
at the mid-span inboard trim tab, ran chordwise to the spar, and turned
along the spar for about an inch. The crack originated from a hole in
the main rotor blade skin. Subsequent investigations revealed that the
manufacturing process utilized to drill the holes in the main rotor
blade skin can allow a fatigue crack to originate at these holes and
propagate in the skin. That condition, if not corrected, could result
in failure of a main rotor blade and subsequent loss of control of the
helicopter.
This AD supersedes AD 98-12-19, Amendment 39-10712 (63 FR 43299,
August 13, 1998), that required the same inspections as this AD.
However, since the issuance of that AD, it has been determined that
continued inspections are inadequate to ensure continued operational
safety and that mandatory terminating action is required to permanently
resolve this unsafe condition. Therefore, this AD mandates replacement
of all the affected main rotor blades prior to further flight after
November 15, 1998.
The FAA has reviewed RHC R44 Service Bulletin SB-27B, Revision B,
which recommends replacing daily preflight inspections with repetitive
inspections at intervals not to exceed 5 hours TIS and clarifies the
inspection procedure. The FAA has also reviewed RHC R44 Service
Bulletin SB-28, which describes procedures for main rotor blade
replacement and recommends replacement by December 31, 1998. Both
service bulletins are dated June 18, 1998.
RHC has also issued a Safety Alert to all Model R44 helicopter
owners, operators, and service centers which states that long term
usage of main rotor blades, part number (P/N) C016-1, is not
recommended. RHC recently commented to Rules Docket No. 98-SW-25-AD (AD
98-12-19). RHC states that AD 98-12-19 should not permit visual
inspections of main rotor blade, P/N C016-1, to continue indefinitely,
and requests that the compliance procedures be modified to require the
installation of redesigned main rotor blades, P/N C016-2, to ``avoid
possible catastrophic failure.'' The commenter also requests that NOTE
5 reference ``Revision B of R44 Service Bulletin 27'' for blade
inspection and ``R44 Service Bulletin 28'' for blade replacement. The
FAA concurs that as the TIS and total number of repetitive inspections
on these main rotor blades increase, so does the possibility for a
crack to develop and remain undetected. Based on that re-evaluation,
the FAA has determined that the required compliance time for main rotor
blade replacement should be earlier than the date stated in RHC R44
Service Bulletin SB-28 in order to ensure public safety.
Since an unsafe condition has been identified that is likely to
exist or develop on other RHC Model R44 helicopters of the same type
design, the FAA issued priority letter AD 98-22-16 to require
repetitively inspecting both holes on both the upper and lower surfaces
of each main rotor blade for cracks until the main rotor blades are
replaced with redesigned main rotor blades. The main rotor blades must
be replaced prior to further flight after November 15, 1998.
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 October 22, 1998 to all known U.S. owners and operators of
RHC Model R44 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 96 helicopters of U.S. registry will be
affected by this AD, that it will take approximately 2 work hours per
helicopter to perform the inspections and 10 work hours to replace both
main rotor blades on each helicopter, and the average labor rate is $60
per work hour. Required parts will cost approximately $3,900 per main
rotor blade. Based on these figures, the total cost impact of the AD on
U.S. operators is estimated to be $817,920, assuming one inspection and
replacement of both main rotor blades on all helicopters.
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. 98-SW-56-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.
[[Page 62933]]
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 removing Amendment 39-10712 (63 FR
43299, August 13, 1998), and by adding a new airworthiness directive
(AD), Amendment 39-10874, to read as follows:
AD 98-22-16 Robinson Helicopter Company: Amendment 39-10874. Docket
No. 98-SW-56-AD. Supersedes AD 98-12-19, Amendment 39-10712, Docket
No. 98-SW-25-AD.
Applicability: Model R44 helicopters, serial numbers (S/N) 0002
through 0486, with main rotor blades, part number (P/N) C016-1,
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
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 (f) 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 a main rotor blade and subsequent loss of
control of the helicopter, accomplish the following:
(a) Within the next 5 hours time-in-service (TIS), perform a
dye-penetrant inspection of the main rotor blade skin around both
inboard trim tab alignment rivets as follows, referring to Figure 1.
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[GRAPHIC] [TIFF OMITTED] TR10NO98.000
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(1) Remove all paint around both rivets, exposing an area of
approximately 3/4'' in diameter, at the inboard trim tab on the top
and bottom of each main rotor blade (4 places per main rotor blade).
Use 180 grit or finer abrasive paper, followed by 600 grit or finer
paper to eliminate course sanding marks. Sand only in a spanwise
direction. Do not use chemical paint strippers.
(2) Inspect the main rotor blade skin around the rivets on the
upper and lower surfaces (4 locations) using a dye-penetrant
inspection method.
Note 2: Chordwise cracks in the paint up to 2 inches long which
are located along either inboard or outboard edge of the trim tab
are acceptable.
(b) Clean the sanded areas prepared in accordance with paragraph
(a) of this AD with 111-Trichloroethane or methyl ethyl ketone (MEK)
and then apply clear lacquer to seal the unpainted areas.
Note 3: Do not bend the inboard main rotor blade tabs from their
present position or utilize them for any subsequent main rotor blade
tracking adjustment.
(c) Thereafter, prior to the first flight of each day, or at
intervals not to exceed 5 hours TIS, whichever occurs first, using a
5-power or higher magnifying glass, visually inspect both upper and
lower main rotor blade skin surfaces around the inboard trim tab
rivets (4 locations) for cracks.
(d) If a crack is found, replace the main rotor blade with an
airworthy main rotor blade before further flight.
(e) Prior to further flight after November 15, 1998, install a
set of main rotor blades, main rotor blade P/N C016-2. This
constitutes terminating action for the inspections required by this
AD.
Note 4: Robinson Helicopter Company R44 Service Bulletin SB-27B,
Revision B, and Robinson Helicopter Company Service Bulletin SB-28,
both dated June 18, 1998, pertain to the subject of this AD.
(f) 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, 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 5: 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.
(g) Special flight permits will not be issued.
(h) This amendment becomes effective on November 10, 1998, to
all persons except those persons to whom it was made immediately
effective by Priority Letter AD 98-22-16, issued October 22, 1998,
which contained the requirements of this amendment.
Issued in Fort Worth, Texas, on November 1, 1998.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 98-30046 Filed 11-9-98; 8:45 am]
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