[Federal Register Volume 61, Number 199 (Friday, October 11, 1996)]
[Proposed Rules]
[Pages 53339-53340]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-26127]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 96-SW-04-AD]


Airworthiness Directives; Sikorsky Aircraft-Manufactured Model S-
64E 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 Sikorsky Aircraft-
manufactured Model S-64E and S-64F helicopters, that currently requires 
initial and repetitive inspections of the main gearbox assembly second 
stage lower planetary plate (plate) for cracks, and removal and 
replacement of the plate if cracks are found; and daily inspections of 
certain main transmission oil filter packs for magnesium chips, and 
removal and replacement of the main transmission if chips are found. 
The AD also provides for reworking and re-identifying the plate, as 
well as establishes a retirement life for the plate, including those 
that have been reworked and re-identified. This action would require, 
for Model S-64E helicopters, inspections and rework of the plate and 
establishes a new retirement life for the plate. This proposal is 
prompted by the type certificate holder's reports that four plates were 
discovered to have cracks, three of which had been reworked in 
accordance with the existing AD. The actions specified by the proposed 
AD are intended to add another plate to the applicability of the AD, 
remove the requirements of AD 77-20-01 for the Model S-64F and prevent 
failure of the plate on the Model S-64E due to fatigue cracking, which 
could lead to failure of the main gearbox and subsequent loss of 
control of the helicopter.

DATES: Comments must be received by December 10, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Assistant Chief Counsel, Attention: 
Rules Docket No. 96-SW-04-AD, 2601 Meacham Blvd., 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 Erickson Air-Crane Co., 3100 Willow Springs Rd., P.O. Box 
3247, Central Point, OR 97502. This information may be examined at the 
FAA, Office of the Assistant Chief Counsel, 2601 Meacham Blvd., Room 
663, Fort Worth, Texas.

FOR FURTHER INFORMATION CONTACT: Mr. Uday Garadi, Aerospace Engineer, 
FAA, Rotorcraft Directorate, Rotorcraft Certification Office, 2601 
Meacham Blvd., Fort Worth, Texas 76137; telephone (817) 222-5157, fax 
(817) 222-5961.

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 No. 96-SW-04-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. 96-SW-04-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 
76137.

Discussion

    On September 19, 1977, the FAA issued AD 77-20-01, Amendment 39-
3045 (42 FR 51565, September 29, 1977), that was subsequently revised 
by Amendment 39-3064 (42 FR 56600, October 27, 1977), that was issued 
on October 18, 1977, to require initial and repetitive inspections of 
the Model S-64E and S-64F plates for cracks that initiate at and 
radiate from the lightening holes in the plate web, and removal and 
replacement of the plates if cracks are found; and daily inspections of 
certain main transmission oil filter packs for magnesium chips, and 
removal and replacement of the main transmission if chips are found. 
The AD also provided for reworking and re-identifying the plates, as 
well as established a retirement life for the plates, including those 
that have been reworked and re-identified. That action was prompted by 
the manufacturer's discovery of plates with cracks in the area of the 
lightening holes. The requirements of that AD are intended to prevent 
cracking and failure of the plates.
    Since the issuance of that AD, the type certificate holder, 
Erickson Air-Crane Co. (Erickson), reported that a cracked plate was 
found during the overhaul of a main gearbox assembly. Three additional 
cracked plates were found during inspections and maintenance of main 
gearboxes. These plates had been reworked in accordance with the 
existing AD and therefore were not subject to recurring inspections. 
Erickson has issued revised service bulletins for inspections of 
plates, P/N 6435-20229-102, that have been reworked in accordance with 
the existing service bulletins, and P/N 6435-20229-104, which have a 
total time-in-service (TIS) of 1,500 hours or more. This AD applies 
only to the Model S-64E helicopters because the Model S-64F helicopters 
utilize a different part-numbered planetary plate. The Model S-64F 
helicopters, with the different part-numbered planetary plates, are 
being addressed in a separate AD.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other Sikorsky Aircraft-manufactured Model S-64E 
helicopters of the same type design, the proposed AD would supersede AD 
77-20-01 to require, at 1,300 hours TIS, a fluorescent magnetic 
particle inspection of the plate, P/N 6435-20229-102 or P/N

[[Page 53340]]

643520229-102-TS-107, for cracks, replacement of the plate if a crack 
is found, and reworking the plate if no crack is found. The proposed AD 
also requires, at 1,500 hours TIS, and thereafter at intervals not to 
exceed 70 hours TIS, for reworked plate, P/N 6435-20229-102 or P/N 
6435-20229-102-TS-107, and for plate, P/N 6435-20229-104, a borescope 
inspection for cracks and replacement of the plate if a crack is found. 
Finally, these part-numbered plates are to be retired upon reaching 
2,600 hours TIS.
    The FAA estimates that 8 helicopters of U.S. registry would be 
affected by this proposed AD, that it would take approximately 8 work 
hours per helicopter to accomplish the inspections and 56 hours to 
remove and replace the main gearbox assembly, if necessary, and that 
the average labor rate is $60 per work hour. Required parts would cost 
$8,000. Based on these figures, the total cost impact of the proposed 
AD on U.S. operators is estimated to be $94,720; $3,840 to accomplish 
the inspections, and $90,880 to replace the plate in the main gearbox 
assembly in all 8 helicopters, if necessary.
    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 USC 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing Amendment 39-3045 (42 FR 
51565, September 29, 1977) and Amendment 39-3064 (42 FR 56600, October 
27, 1977), and by adding a new airworthiness directive (AD), to read as 
follows:

Erickson Air-Crane Co.: Docket No. 96-SW-04-AD. Supersedes AD 77-20-
01, Amendment 39-3045 and Amendment 39-3064.

    Applicability: Sikorsky Aircraft-manufactured Model S-64E 
helicopters, with main gearbox assembly second stage lower planetary 
plate (plate), part number (P/N) 6435-20229-102, P/N 6435-20229-102-
TS-107, or P/N 6435-20229-104, 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 (d) 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 prevent failure of the plate due to fatigue cracking, which 
could lead to failure of the main gearbox and subsequent loss of 
control of the helicopter, accomplish the following:
    (a) For plate, part number (P/N) 6435-20229-102 and P/N 6435-
20229-102-TS-107, at 1,300 hours total time-in-service (TIS), 
inspect and rework or replace the plate, as appropriate, in 
accordance with the Accomplishment Instructions, paragraph 2A., 
steps (1), and (3) through (11), of Erickson Air Crane Co. Service 
Bulletin No. 64B35-7C, dated November 8, 1995.
    (b) For plate, P/N 6435-20229-104, and for any plate, P/N 6435-
20229-102, that has been reworked and identified with ``TS-107'', at 
1,500 hours TIS and thereafter at intervals not to exceed 70 hours 
TIS, inspect the plate in accordance with the Accomplishment 
Instructions, paragraph 2B., step (1), of Erickson Air-Crane Co. 
Service Bulletin No. 64B35-7C, dated November 8, 1995. If a crack is 
found, replace the main gearbox assembly with an airworthy assembly.
    (c) Retire the plate upon or before reaching 2,600 hours TIS. 
This AD revises the airworthiness limitation section of the 
maintenance manual by establishing a retirement life of 2,600 hours 
TIS for the main gearbox assembly second stage planetary plate, P/N 
6435-20229-102, P/N 6435-20229-102-TS-107, and P/N 6435-20229-104.
    (d) 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, Rotorcraft Certification Office, 
Rotorcraft Directorate, FAA. Operators shall submit their requests 
through an FAA Principal Maintenance Inspector, who may concur or 
comment and then send it to the Manager, Rotorcraft Certification 
Office.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Rotorcraft 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) to operate the helicopter to a location where 
the requirements of this AD can be accomplished.

    Issued in Fort Worth, Texas, on October 4, 1996.
Eric Bries,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 96-26127 Filed 10-10-96; 8:45 am]
BILLING CODE 4910-13-U