[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