[Federal Register Volume 63, Number 156 (Thursday, August 13, 1998)]
[Rules and Regulations]
[Pages 43299-43302]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-21706]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-SW-25-AD; Amendment 39-10712; AD 98-12-19]
RIN 2120-AA64


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) 98-12-19 which was sent 
previously to all known U.S. owners and operators of RHC Model R44 
helicopters by individual letters. This AD requires, within 5 hours 
TIS, a dye penetrant inspection of each main rotor blade skin (blade 
skin) around both inboard trim tab alignment rivet holes. Thereafter, a 
repetitive visual inspection of the blade skin around both inboard trim 
tab alignment rivet holes is required prior to the first flight of each 
day or at intervals not to exceed 5 hours TIS, whichever occurs first. 
This amendment is prompted by an incident in which a crack in the main 
rotor blade resulted in a forced landing. Subsequent investigations 
revealed that the manufacturing process utilized to drill the trim tab 
alignment rivet holes in the blade skin can allow a fatigue crack to 
originate at these holes and propagate in the skin. This condition, if 
not corrected, could result in failure of the main rotor blade and 
subsequent loss of control of the helicopter.

DATES: Effective August 28, 1998, to all persons except those persons 
to whom it was made immediately effective by priority letter AD 98-12-
19, issued on June 2, 1998, which contained the requirements of this 
amendment.
    Comments for inclusion in the Rules Docket must be received on or 
before October 13, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 98-SW-25-AD, 2601 Meacham Blvd., Room 663, 
Fort Worth, Texas 76137.

FOR FURTHER INFORMATION CONTACT: Mr. Fred 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 June 2, 1998, the FAA issued priority 
letter AD 98-12-19, applicable to RHC Model R44 helicopters, which 
requires, within 5 hours TIS, a dye penetrant inspection of the blade 
skin around both inboard trim tab alignment rivet holes. Thereafter, a 
repetitive visual inspection of the blade skin around both inboard trim 
tab alignment rivet holes is required prior to the first flight of each 
day or at intervals not to exceed 5 hours TIS, whichever occurs first. 
If a crack is found, this AD requires replacing the main rotor blade 
with an airworthy main rotor blade before further flight. That action 
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 that started 
at the mid-span inboard trim tab and ran chordwise to the spar where it 
turned along the spar for about an inch. The crack originated from a 
trim tab alignment rivet hole in the blade skin. Subsequent 
investigations revealed that the manufacturing process utilized to 
drill the trim tab alignment rivet holes in the blade skin can allow a 
fatigue crack to originate at these holes and propagate in the skin. 
This condition, if not corrected, could result in failure of the main 
rotor blade and subsequent loss of control of the helicopter.
    Since the unsafe condition described is likely to exist or develop 
on other RHC Model R44 helicopters of the same type design, the FAA 
issued priority letter AD 98-12-19 to prevent failure of the main rotor 
blade and subsequent loss of control of the helicopter. The AD 
requires, within 5 hours TIS, a dye penetrant inspection of the blade 
skin around both inboard trim tab alignment rivet holes. Thereafter, a 
repetitive visual inspection of the blade skin around both inboard trim 
tab alignment rivet holes is required prior to the first flight of each 
day or at intervals not to exceed 5 hours TIS, whichever occurs first. 
If a crack is found, this AD requires replacing the main rotor blade 
with an airworthy main rotor blade before further flight. Installing a 
set of main rotor blades, P/N C016-2, constitutes terminating action 
for the requirements of this AD.
    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 June 2, 1998, to all

[[Page 43300]]

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 inspect the blade skin and 10 work hours per helicopter 
to replace both main rotor blades and that the average labor rate is 
$60 per work hour. Required parts will cost approximately $10,000 per 
main rotor blade set. Based on these figures, the total cost impact of 
the AD on U.S. operators is estimated to be $1,029,120, assuming one 
inspection and replacement of both main rotor blades on all helicopters 
with blades which would terminate the requirements of this AD.

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-25-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:

98-12-19  Robinson Helicopter Company: Amendment 39-10712. Docket 
No. 98-SW-25-AD.

    Applicability: Model R44 helicopters, serial numbers (S/N) 0002 
thru 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 detect main rotor blade skin fatigue cracks which originate 
from the inboard trim tab alignment rivet holes, that could result 
in failure of the main rotor blade and subsequent loss of control of 
the helicopter, accomplish the following:
    (a) Within the next five hours time-in-service (TIS), perform a 
dye penetrant inspection of the blade skin around both inboard trim 
tab alignment rivets as follows, referring to Figure 1.

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[GRAPHIC] [TIFF OMITTED] TR13AU98.003



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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 top 
and bottom of each blade (4 places per 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 blade skin around the rivets on the upper and 
lower surfaces (4 locations) using a dye penetrant 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 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 the upper and 
lower 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) Installation of a set of main rotor blades, P/N C016-2, 
constitutes terminating action for the requirements 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 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 4: 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.

    Note 5: Robinson Helicopter Company R44 Service Bulletin SB-27A, 
revised May 29, 1998, pertains to the subject of this AD.

    (h) This amendment becomes effective on August 28, 1998, to all 
persons except those persons to whom it was made immediately 
effective by Priority Letter AD 98-12-19, issued June 2, 1998, which 
contained the requirements of this amendment.

    Issued in Fort Worth, Texas, on August 5, 1998.
Henry A. Armstrong,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 98-21706 Filed 8-12-98; 8:45 am]
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