[Federal Register Volume 64, Number 183 (Wednesday, September 22, 1999)]
[Rules and Regulations]
[Pages 51200-51202]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-24535]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-SW-46-AD; Amendment 39-11331; AD 99-17-17]
RIN 2120-AA64


Airworthiness Directives; Robinson Helicopter Company 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) 99-17-17 which was sent 
previously to all known U.S. owners and operators of Robinson 
Helicopter Company (RHC) Model R44 helicopters by individual letters. 
This AD requires, prior to further

[[Page 51201]]

flight, replacing certain yoke assemblies with airworthy yoke 
assemblies. This amendment is prompted by an incident in which, during 
cruise flight, the pilot heard a loud bang and no tail rotor 
effectiveness due to a cracked yoke assembly. RHC has identified the 
manufacturing lots associated with the failed yoke assembly. The 
actions specified by this AD are intended to prevent failure of the 
yoke assembly, which could result in loss of main and tail rotor drive 
and subsequent loss of control of the helicopter.

DATES: Effective October 7, 1999, to all persons except those persons 
to whom it was made immediately effective by Emergency Priority Letter 
AD 99-17-17, issued on August 13, 1999, which contained the 
requirements of this amendment.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of October 7, 1999.
    Comments for inclusion in the Rules Docket must be received on or 
before November 22, 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-46-AD, 2601 Meacham Blvd., Room 663, 
Fort Worth, Texas 76137.
    The applicable service information may be obtained from Robinson 
Helicopter Company, 2901 Airport Drive, Torrance, California 90505 
telephone (310) 539-0508, fax (310) 539-5198. This information may be 
examined at the FAA, Office of the Regional Counsel, Southwest Region, 
2601 Meacham Blvd., Room 663, Fort Worth, Texas; or at the Office of 
the Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.

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 August 13, 1999, the FAA issued Emergency 
Priority Letter AD 99-17-17, applicable to RHC Model R44 helicopters, 
which requires, prior to further flight, replacing certain yoke 
assemblies with airworthy yoke assemblies. That action was prompted by 
an incident in which, during cruise flight, the pilot heard a loud bang 
and noticed no tail rotor effectivity after entering autorotation. An 
investigation revealed that the yoke assembly, which connects the main 
rotor gearbox pinion shaft to the forward flexplate, had failed at a 
weld joint due to a crack. The cause of the crack is unknown but still 
under investigation. RHC has identified the manufacturing lots 
associated with the failed yoke. This condition, if not corrected, 
could result in failure of the yoke assembly, loss of main and tail 
rotor drive, and subsequent loss of control of the helicopter.
    The FAA has reviewed RHC R44 Service Bulletin SB-35, dated July 26, 
1999, which prescribes procedures for identifying the manufacturing lot 
for each yoke assembly, part number (P/N) C908-1C, and for removing and 
replacing the yoke assembly.
    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 Emergency Priority Letter AD 99-17-17 to prevent failure of the 
yoke assembly, which could result in loss of main and tail rotor drive 
and subsequent loss of control of the helicopter. The AD requires, 
prior to further flight, replacing the yoke assembly, P/N C908-1C, from 
Lot Nos. 36B, 37, and 38, with an airworthy yoke assembly from a lot 
other than 36B, 37, or 38. The actions must be accomplished in 
accordance with the service bulletin described previously. The short 
compliance time involved is required because the previously described 
critical unsafe condition can adversely affect the structural integrity 
of the helicopter. Therefore, replacing any yoke assembly, P/N C908-1C, 
from Lot Nos. 36B, 37, and 39, is required prior to 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 August 13, 1999 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 75 helicopters of U.S. registry will be 
affected by this AD, that it will take approximately 2 work hours per 
helicopter to accomplish the required actions, and the average labor 
rate is $60 per work hour. Required parts will cost approximately $840 
per helicopter. Based on these figures, the total cost impact of the AD 
on U.S. operators is estimated to be $72,000, assuming that the yoke 
assembly is replaced in each helicopter.

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-46-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

[[Page 51202]]

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, Incorporation by 
reference, 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 99-17-17  Robinson Helicopter Company: Amendment 39-11331. Docket 
No. 99-SW-46-AD.

    Applicability: Model R44 helicopters, 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 (c) 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 prior to further flight, unless 
accomplished previously.
    To prevent failure of the yoke assembly, which could result in 
loss of main and tail rotor drive and subsequent loss of control of 
the helicopter, accomplish the following:
    (a) Determine, by inspection, if the yoke assembly, part number 
(P/N) C908-1C, from Lot No. 36B, 37, or 38 is installed.

    Note 2: Yoke assemblies, P/N C908-1C, from Lot Nos. 36B, 37, and 
38 were installed as original equipment in R44 helicopters, Serial 
Numbers (S/N) 0219 and 0535 through 0608 (except S/N's 0565, 0582, 
and 0592).

    (b) Replace any yoke assembly, P/N C908-1C, from Lot No. 36B, 
37, or 38, with an airworthy yoke assembly from a lot other than 
36B, 37, or 38 in accordance with the compliance procedure, steps 2 
through 12, of Robinson Helicopter Company R44 Service Bulletin SB-
35, dated July 26, 1999.
    (c) 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 3: 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.

    (d) Special flight permits will not be issued.
    (e) The replacement of the yoke assembly shall be done in 
accordance with the compliance procedure, steps 2 through 12, of 
Robinson Helicopter Company R44 Service Bulletin SB-35, dated July 
26, 1999. This incorporation by reference was approved by the 
Director of the Federal Register in accordance with 5 U.S.C. 552(a) 
and 1 CFR part 51. Copies may be obtained from Robinson Helicopter 
Company, 2901 Airport Drive, Torrance, California 90505 telephone 
(310) 539-0508, fax (310) 539-5198. Copies may be inspected at the 
FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham 
Blvd., Room 663, Fort Worth, Texas; or at the Office of the Federal 
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
    (f) This amendment becomes effective on [insert date 15 days 
after date of publication in the Federal Register], to all persons 
except those persons to whom it was made immediately effective by 
Emergency Priority Letter AD 99-17-17, issued August 13, 1999, which 
contained the requirements of this amendment.

    Issued in Fort Worth, Texas, on September 13, 1999.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 99-24535 Filed 9-21-99; 8:45 am]
BILLING CODE 4910-13-U