[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


BILLING CODE 4910-13-C

[[Page 62935]]

    (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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