[Federal Register Volume 64, Number 10 (Friday, January 15, 1999)]
[Rules and Regulations]
[Pages 2558-2559]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-910]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-SW-79-AD; Amendment 39-10991; AD 99-02-02]
RIN 2120-AA64
Airworthiness Directives; Robinson Helicopter Company (RHC) Model
R22 Helicopters
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
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SUMMARY: This amendment supersedes an existing airworthiness directive
(AD), applicable to RHC Model R22 helicopters, that currently requires
initial and repetitive inspections of the forward flexplate (flexplate)
at specified time intervals. This amendment also supersedes an existing
priority letter AD that requires, within 25 hours time-in-service (TIS)
or 15 calendar days, whichever occurs first, replacing the flexplate
with an airworthy flexplate. This amendment requires the same
replacement as the priority letter AD. This amendment is prompted by an
accident in which the flexplate failed, causing loss of main rotor
drive and rupture of the fuel tank. The actions specified by this AD
are intended to prevent failure of the flexplate, which could result in
failure of the main rotor drive system and subsequent loss of control
of the helicopter.
DATES: Effective February 1, 1999.
Comments for inclusion in the Rules Docket must be received on or
before March 16, 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-79-AD, 2601 Meacham Blvd., Room 663,
Fort Worth, Texas 76137.
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 (817) 627-5210.
SUPPLEMENTARY INFORMATION: The FAA issued priority letter AD 94-11-01
on May 18, 1994 and AD 95-06-07 (60 FR 14619, March 20, 1995) on March
10, 1995. AD 95-06-07 superseded priority letter AD 94-11-01. Both AD's
were prompted by three accidents involving failure of the flexplate.
Both AD's also required an initial dye-penetrant inspection and
repetitive visual inspections of the flexplate at intervals not to
exceed 50 hours TIS, after accumulating 500 hours TIS or 2 years
service life, whichever occurred first. AD 95-06-07 also exempted
flexplate, part number (P/N) A947-1 E, and subsequent FAA-approved
revisions, from the requirements of that AD, and provided that
installation of flexplate, P/N A947-1 E or a subsequent FAA-approved
revision to that P/N, constituted a terminating action for the
requirements of that AD.
After the issuance of AD 95-06-07, another accident occurred in
which the flexplate, P/N A947-1, failed, causing loss of the main rotor
drive and rupture of the fuel tank. Prompted by that accident, the FAA
determined that the repetitive inspections required by AD 95-06-07 did
not correct the unsafe condition. Therefore, the FAA issued priority
letter AD 98-14-08 on June 25, 1998, which specifies procedures for
replacing flexplate, P/N A193-1 or P/N A947-1 A through D, with
flexplate, P/N A947-1 E or F. Also, the FAA intended that Priority
Letter AD 98-14-08 (Docket 98-SW-33-AD) supersede AD 95-06-07 (Docket
94-SW-22-AD), but did not state that in Priority Letter AD 98-14-08. To
eliminate any confusion, this AD supersedes Priority Letter AD 98-14-08
(Docket 98-SW-30-AD), and AD 95-06-07, Amendment 39-9177 (Docket 94-SW-
22-AD). This action is intended to prevent failure of the flexplate,
which could result in failure of the main rotor drive system and
subsequent loss of control of the helicopter.
Since an unsafe condition has been identified that is likely to
exist or develop on other RHC Model R22 helicopters of the same type
design, this AD supersedes AD 95-06-07 and priority letter AD 98-14-08
to prevent failure of the flexplate, which could result in failure of
the main rotor drive system and subsequent loss of control of the
helicopter. The short compliance time involved is required because the
previously described critical unsafe condition can adversely affect the
controllability of the helicopter. Therefore, replacing the flexplate
with an airworthy flexplate is required within 25 hours TIS or 15
calendar days, whichever occurs first, and this AD must be issued
immediately.
Since a situation exists that requires the immediate adoption of
this regulation, it is found that notice and opportunity for prior
public comment hereon are impracticable, and that good cause exists for
making this amendment effective in less than 30 days.
The FAA estimates that 100 helicopters will be affected by this AD,
that it will take approximately 1.5 work hours to replace the
flexplate, and that the average labor rate is $60 per work hour.
Required parts will cost approximately $536 per helicopter. Based on
these figures, the total cost impact of the AD on U.S. operators is
estimated to be $62,600.
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.
[[Page 2559]]
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-79-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 removing Amendment 39-9177 (60 FR
14619, March 20, 1995), and by adding a new airworthiness directive
(AD), Amendment 39-10991, to read as follows:
AD 99-02-02 Robinson Helicopter Company: Amendment 39-10991. Docket
No. 98-SW-79-AD. Supersedes AD 95-06-07, Amendment 39-9177, Docket
No. 94-SW-22-AD, and Priority Letter AD 98-14-08, Docket No. 98-SW-
30-AD.
Applicability: Model R22 helicopters, with forward flexplate
(flexplate), part number (P/N) A947-1, A through D, or P/N A193-1,
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 (b) 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 within 25 hours time-in-service (TIS) or 15
calendar days, whichever occurs first, unless accomplished
previously.
To prevent failure of the flexplate, which could result in
failure of the main rotor drive system and subsequent loss of
control of the helicopter, accomplish the following:
(a) Remove the flexplate and replace it with an airworthy
flexplate, P/N A947-1 E or F, in accordance with following:
(1) With the clutch disengaged, support the forward end of the
clutch shaft, P/N A166-1, and remove the forward flexplate, P/N
A947-1 or A193-1, and the intermediate flexplate, P/N A947-2 or P/N
A193-2. Record any shim locations for reinstallation.
(2) Install a zero TIS forward flexplate, P/N A947-1 E or F, and
any shims that were noted. Use washers, P/N AN960-516 or AN960-516L,
under the nut so that 2-4 threads are exposed. Torque the fasteners.
(3) Inspect the sheave alignment.
(4) Inspect the clutch shaft, P/N A166-1, angle.
(5) Reinstall the intermediate flexplate and shim.
Note 2: Robinson R22 Maintenance Manual, Sections 1.320, 7.230,
7.240, and 7.330 pertain to paragraphs (a)(2), (a)(3), (a)(4), and
(a)(5) of this AD, respectively.
Note 3: Robinson Helicopter Company R22 Service Bulletin SB-75,
dated November 22, 1994, pertains to the subject of this AD.
(b) 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.
(c) Special flight permits may be issued in accordance with
sections 21.197 and 21.199 of the Federal Aviation Regulations (14
CFR 21.197 and 21.199) to operate the helicopter to a location where
the requirements of this AD can be accomplished.
(d) This amendment becomes effective on February 1, 1999.
Issued in Fort Worth, Texas, on January 6, 1999.
Henry A. Armstrong,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 99-910 Filed 1-14-99; 8:45 am]
BILLING CODE 4910-13-U
