Airworthiness directives: Robinson Helicopter Co.,
[Federal Register: August 13, 1998 (Volume 63, Number 156)]
[Rules and Regulations]
[Page 43299-43302]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr13au98-8]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
[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.
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
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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 filedin 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
-
The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
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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. 98-21706Filed8-12-98; 8:45 am]
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