[Federal Register Volume 59, Number 229 (Wednesday, November 30, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-25912]
[[Page Unknown]]
[Federal Register: November 30, 1994]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 94-SW-02-AD]
Airworthiness Directives; Schweizer Aircraft Corporation and
Hughes Helicopters, Inc. Model 269A, 269A-1, 269B, 269C, and TH-55A
Series Helicopters
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes the supersedure of an existing
airworthiness directive (AD), applicable to Schweizer Aircraft
Corporation and Hughes Helicopters, Inc. Model 269A, 269A-1, 269B,
269C, and TH-55A series helicopters with certain main rotor (M/R) drive
shafts installed, that currently requires a one-time radiographic
inspection or a non-destructive inspection of certain M/R drive shafts
for cracks, distortion, corrosion, or other surface damage, at
specified time intervals or upon the occurrence of specified
conditions. This action would require the same inspections as the
previous AD, but would expand the applicability of certain inspections
to additional models of the affected helicopters and would exclude
certain M/R drive shafts from certain inspections. This proposal is
prompted by a reevaluation of the previous AD as a result of a comment
suggesting the need to expand the applicability of certain inspections
to additional models of the affected helicopters and to exclude certain
M/R drive shafts from certain inspections. The actions specified by the
proposed AD are intended to prevent structural failure of the M/R drive
shaft, separation of the M/R from the helicopter, and subsequent loss
of control of the helicopter.
DATES: Comments must be received by January 30, 1995.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Office of the Assistant Chief Counsel, Attention:
Rules Docket No. 94-SW-02-AD, 2601 Meacham Boulevard, Room 663, Fort
Worth, Texas 76137. Comments may be inspected at this location between
9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal
holidays.
The service information referenced in the proposed rule may be
obtained from Schweizer Aircraft Corporation, P.O. Box 147, Elmira, New
York 14902. This information may be examined at the FAA, Office of the
Assistant Chief Counsel, 2601 Meacham Boulevard, Room 663, Fort Worth,
Texas.
FOR FURTHER INFORMATION CONTACT: Mr. Raymond J. O'Neill, Aerospace
Engineer, New York Aircraft Certification Office, ANE-170, FAA, New
England Region, 181 South Franklin Avenue, Room 202, Valley Stream, New
York 11581, telephone (516) 791-7422, fax (516) 791-9024.
SUPPLEMENTARY INFORMATION:
Comments Invited
Interested persons are invited to participate in the making of the
proposed 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 above. All
communications received on or before the closing date for comments,
specified above, will be considered before taking action on the
proposed rule. The proposals contained in this notice may be changed in
light of the comments received.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with
the substance of this proposal will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this notice must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 94-SW-02-AD.'' The postcard will be date stamped and
returned to the commenter.
Availability of NPRMs
Any person may obtain a copy of this NPRM by submitting a request
to the FAA, Office of the Assistant Chief Counsel, Attention: Rules
Docket No. 94-SW-02-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas
76137.
Discussion
On July 13, 1993, the FAA issued AD 93-14-06, Amendment 39-8630 (58
FR 53120, October 14, 1993), to require either a radiographic or a non-
destructive inspection of certain main rotor (M/R) drive shafts for
cracks, distortion, corrosion, or other surface damage. That action was
prompted by an accident resulting from a structural failure of a drive
shaft and reports of stress concentrations caused by deep manufacturing
tooling marks on the inside surface of the drive shaft. That condition,
if not corrected, could result in structural failure of the M/R drive
shaft, separation of the M/R from the helicopter, and subsequent loss
of control of the helicopter.
Since the issuance of that AD, a commenter states that the FAA
incorrectly required inspections of replacement drive shafts with
serial number prefixes of ``SZ'' or ``ZS''. The drive shafts with
serial numbers containing the ``SZ'' and ``ZS'' prefixes were excluded
from the requirements of paragraph (a) of that AD and should have been
excluded from the requirements of paragraph (b), but were not. Also, in
paragraph (a)(3) of the AD, the commenter states that the FAA
incorrectly limited the applicability of the inspection requirements to
the Model 269C helicopter for inspection of those M/R drive shafts with
serial numbers S1112 and higher. It is the commenter's position that
the inspection required by paragraph (a)(3) should apply to all M/R
drive shafts with serial numbers S1112 and higher installed on any
Model 269 series helicopters, and should not be limited to those
installed on the Model 269C as was stated in that AD. The FAA agrees
with the commenter and is hereby proposing to supersede AD 93-14-06 to
incorporate the recommended changes.
Since an unsafe condition has been identified that is likely to
exist or develop on other Schweizer Aircraft Corporation and Hughes
Helicopters, Inc. Model 269A, 269A-1, 269B, 269C, and TH-55A series
helicopters of the same type design, the proposed AD would supersede AD
93-14-06 to require a one-time radiographic inspection or a non-
destructive inspection of the applicable M/R drive shafts of all Model
269 series helicopters. The proposed AD would also change paragraph (b)
of AD 93-14-06 to exclude those replacement drive shafts having an
``SZ'' or ``ZS'' prefix from mandatory inspections prior to their
installation.
The FAA estimates that 1,364 helicopters of U.S. registry would be
affected by this proposed AD, that it would take approximately 10 work
hours per helicopter to accomplish the proposed actions, and that the
average labor rate is $60 per work hour. Based on these figures, the
total cost impact of the proposed AD on U.S. operators is estimated to
be $818,400.
The regulations proposed herein would 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
proposal would not have sufficient federalism implications to warrant
the preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this proposed
regulation (1) is not a ``significant regulatory action'' under
Executive Order 12866; (2) is not a ``significant rule'' under the DOT
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979);
and (3) if promulgated, will not have a significant economic impact,
positive or negative, on a substantial number of small entities under
the criteria of the Regulatory Flexibility Act. A copy of the draft
regulatory evaluation prepared for this action is contained in the
Rules Docket. A copy of it may be obtained by contacting 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.
The Proposed Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration proposes to amend
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. App. 1354(a), 1421 and 1423; 49 U.S.C.
106(g); and 14 CFR 11.89.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by removing Amendment 39-8630, (58 FR
53120, October 14, 1993) and by adding a new airworthiness directive
(AD), to read as follows:
Schweizer Aircraft Corporation and Hughes Helicopters Inc.: Docket
No. 94-SW-02-AD. Supersedes AD 93-14-06, Amendment 39-8630.
Applicability: Model 269A, 269A-1, 269B, 269C, and TH-55A series
helicopters, with main rotor (M/R) drive shafts, part numbers (P/N)
269A5305-3 and 269A5305-11, except those M/R drive shafts having a
serial number with a prefix of ``SZ'' or ``ZS'', installed,
certificated in any category.
Compliance: Required as indicated, unless accomplished
previously.
To prevent structural failure of the M/R drive shaft, separation
of the M/R from the helicopter, and subsequent loss of control of
the helicopter, accomplish the following:
(a) Inspect the M/R drive shaft for cracks, distortion,
corrosion, or other surface damage, using either the radiographic
inspection procedure or the non-destructive inspection procedure in
accordance with Part I of Schweizer Service Bulletin B-255.1 (SB),
dated February 1, 1993. Conduct this inspection at the time
intervals and under the conditions stated in the following:
(1) Inspect M/R drive shafts with serial numbers (S/N) S0001
through S1111, and any drive shaft without an ``S'' prefix on the S/
N, having less than 1,100 hours time-in-service (TIS) on the
effective date of this AD--
(i) At the next removal of the drive shaft;
(ii) Within the next 600 hours TIS;
(iii) Prior to attaining 1,200 hours total TIS; or
(iv) Within 1 year after the effective date of this AD,
whichever occurs first.
(2) Inspect M/R drive shafts with S/N S0001 through S1111, and
any drive shaft without an ``S'' prefix on the S/N with 1,100 hours
or more TIS on the effective date of this AD--
(i) Within the next 100 hours TIS; or
(ii) At the next removal of the drive shaft; or
(iii) Within 1 year after the effective date of this AD,
whichever occurs first.
(3) Inspect M/R drive shafts with S/N S1112 and higher,
regardless of the number of the total hours TIS on the effective
date of this AD--
(i) Within the next 25 hours TIS;
(ii) At the next removal of the drive shaft; or
(iii) Within 1 year after the effective date of this AD,
whichever occurs first.
(4) Inspect the M/R drive shaft before further flight if M/R
vibrations occur that cannot be corrected with track and balance
procedures, or if M/R track and balance procedures are required more
than once within a 25-hour TIS interval.
(b) Inspect any replacement M/R drive shaft, except those that
have a serial number with a prefix of ``SZ'' or ``ZS'', prior to
installation in accordance with the procedures in Part I of the SB,
dated February 1, 1993.
(c) Replace any unairworthy M/R drive shaft with an airworthy M/
R drive shaft before further flight.
(d) 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, New York 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, New York Aircraft Certification Office.
Note: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the New York Aircraft Certification Office.
(e) 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) only for those helicopters that do not
exhibit M/R vibrations due to uncorrected out-of-track or out-of-
balance conditions specified in paragraph (a)(4) of this AD. The
special flight permit allows flight of the helicopter to a location
where the requirements of this AD can be accomplished.
Issued in Fort Worth, Texas, on November 23, 1994.
James D. Erickson,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 94-25912 Filed 11-29-94; 8:45 am]
BILLING CODE 4910-13-P
