[Federal Register Volume 61, Number 117 (Monday, June 17, 1996)]
[Proposed Rules]
[Pages 30548-30550]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-15214]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-SW-17-AD]


Airworthiness Directives; Schweizer Aircraft Corporation and 
Hughes Helicopters, Inc. Model 269A, 269A-1, 269B, and TH-55A 
Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to supersede an existing airworthiness 
directive (AD), applicable to Schweizer Aircraft Corporation and Hughes 
Helicopters, Inc. Model 269A, 269A-1, 269A-2, and 269B helicopters, 
that currently requires initial and repetitive inspections of the main 
rotor thrust bearing (bearing) for bearing rotational roughness, 
corrosion, inadequate lubrication, physical damage, or excessive zinc 
chromate paste or moisture. This action would require the same initial 
and repetitive inspections required by the existing AD, but would 
extend the retirement life for certain bearings, and would remove the 
Model 269A-2 helicopter from, and add the Model TH-55A helicopters to 
the applicability of this AD. This proposal is prompted by an FAA 
analysis of service information issued by the

[[Page 30549]]

manufacturer that extends the retirement life for certain bearings. The 
actions specified by the proposed AD are intended to prevent failure of 
the bearing, loss of the main rotor, and subsequent loss of control of 
the helicopter.

DATES: Comments must be received by August 16, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Assistant Chief Counsel, Attention: 
Rules Docket No. 94-SW-17-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 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, Room 663, 2601 Meacham Blvd., Fort Worth, 
Texas.

FOR FURTHER INFORMATION CONTACT:
Mr. Ray O'Neill, Aerospace Engineer, Airframe and Propulsion Branch, 
New York Aircraft Certification Office, FAA, New England Region, 10 5th 
Street, Valley stream, New York 11581, telephone (516) 256-7505, fax 
(516) 568-2716.

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. 94-SW-17-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-17-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 
76137

Discussion

    On October 11, 1968, the FAA issued AD 68-21-05, Amendment 39-672 
(33 FR 15543, October 19, 1968), to require, for Model 269A 
helicopters, serial numbers (S/N) 0011 through 0979 (except Model TH-
55A helicopters), Model 269A-1 helicopters, S/N 0001 through 0041, 
Model 269A-2 helicopter, S/N 0001, and Model 269B, S/N 0001 through 
0370, an initial inspection at 25 hours time-in-service (TIS) and 
thereafter, repetitive inspections at 150 hours TIS intervals of the 
bearing, part number (P/N 269A5050-50 or P/N 269A5050-51, for bearing 
corrosion, inadequate lubrication, physical damage, or evidence of 
excessive zinc chromate paste or moisture; and, to establish a bearing 
retirement life of 300 hours TIS. The AD was revised and issued on July 
24, 1970 (35 FR 12532, August 6, 1970) to require, for bearings, P/N 
269A5050-73, repetitive inspections at 600 hours TIS intervals for 
bearing corrosion, rust, freedom of rotation, looseness, binding, 
nicks, burrs, cracks, and inadequate lubrication; and to establish a 
bearing retirement life of 1,800 hours TIS. These actions were prompted 
by several reports of failures of the bearings in military-use 
helicopters (Model TH-55a) that were equipped with the same bearings. 
That condition, if not corrected, could result in failure of the main 
rotor thrust bearing, loss of the main rotor, and subsequent loss of 
control of the helicopter.
    Since the issuance of that AD, Hughes Helicopters, Inc., issued a 
report (Hughes Report JS-10-3, Revised May 4, 1979), which stated that 
the retirement life for the bearing, P/N 269A5050-73, should be 
extended from 1,800 hours TIS to 3,000 hours TIS. There have been no 
reports of failures of that bearing since the issuance of AD 68-21-05. 
In 1979, the FAA incorporated the 3,000 hours TIS retirement life into 
Type Certificate Data Sheet 4H12, Revision 19, which governs Schweizer 
Aircraft Corporation Model 269A, 269A-1, 269B, and former TH-55A 
helicopters. Additionally, the Model 269A-2 Serial No. 0001) was 
deleted from that Type Certificate Data Sheet. Therefore, the Model 
269A-2 is removed from the applicability of this AD. Finally the Model 
TH-55A helicopter was omitted from the applicability of the existing 
AD, and has been added to the applicability of this AD.
    Since an unsafe condition has been identified that is likely to 
exist or develop another Schweizer Aircraft Corporation and Hughes 
Helicopters, Inc. Model 269A, 269A-1, 269B, and TH-55A helicopters of 
the same type design, the proposed AD would supersede AD 68-21-05 to 
require the same initial and repetitive inspections required by the 
existing AD, but extend the retirement life for bearings, P/N 269A5050-
73, from 1,800 hours TIS to 3,000 hours TIS.
    The FAA estimates that 500 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 proposed actions, and that the 
average labor rate is $60 per work hour. Required parts would cost 
approximately $1,890 per helicopter. Based on these figures, the total 
cost impact of the proposed AD on U.S. operators is estimated to be 
$1,185,000.
    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.

[[Page 30550]]

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, and 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing Amendment 39-1055 (35 FR 
12532, August 6, 1970), and Amendment 39-672 (33 FR 15543, October 19, 
1968), and by adding a new airworthiness directive (AD), to read as 
follows:

Schweizer Aircraft Corporation and Hughes Helicopters, Inc.: Docket 
No. 94-SW-17-AD. Supersedes AD 68-21-05, Amendment 39-1055 and 
Amendment 39-672.

    Applicability: Model 269A helicopters, serial numbers (S/N) 0011 
through 1109, Model 269A-1 helicopters, S/N 0001 through 0041, Model 
269B, S/N 0001 through 0444, and Model TH-55A, with main rotor 
thrust bearing, part number (P/N) 269A5050-50, -51 or -73, 
installed, certified 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 (g) 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) after 
the effective date of this AD, unless accomplished previously.
    To prevent failure of the main rotor thrust bearing, loss of the 
main rotor, and subsequent loss of control of the helicopter, 
accomplish the following:
    (a) From available helicopter records, determine the TIS of the 
appropriate main rotor thrust bearing (bearing), part number (P/N) 
269A5050-50, 269A5050-51, or 269A5050-73.
    (1) If the TIS on the bearing, P/N 269A5050-50 or -51, equals or 
exceeds 300 hours TIS, replace the bearing before further flight.
    (2) If the TIS on the hearing, P/N 269A5050-50 or -51, equals or 
exceeds 275 hours TIS, retire the bearing from service within 25 
hours TIS after the effective date of this AD.
    (b) Inspect bearing, P/N 269A5050-50 or -51, for rotational 
roughness, corrosion, inadequate lubrication, physical damage, 
moisture or inadequate drainage due to build-up of zinc chromate 
paste in accordance with Step II, paragraph b of Schweizer Service 
Notice (SSN) No. N-59, dated October 9, 1968.
    (1) If bearing rotational roughness, corrosion, inadequate 
lubrication, physical damage, moisture or inadequate drainage due to 
build-up of zinc chromate paste is found, replace the bearing with 
an airworthy bearing.
    (2) If no bearing rotational roughness, corrosion, lack of 
lubrication, physical damage, moisture or inadequate drainage due to 
build-up of zinc chromate paste is found, thereafter, inspect the 
bearing in accordance with this paragraph upon attaining an 
additional 150 hours TIS.
    (3) For replacement bearings, inspect in accordance with this 
paragraph upon attaining 150 hours TIS, unless the bearing reaches 
its 300 hour TIS retirement life limit prior to this inspection.
    (c) For bearing, P/N 269A5050-73:
    (1) Inspect the bearing for corrosion, rust, freedom of 
rotation, looseness, binding, nicks, burrs, cracks and lubrication. 
Thereafter, inspect the bearing at intervals not to exceed 600 hours 
TIS.
    (2) As necessary, repack the bearing cavity in accordance with 
Schweizer Aircraft Corporation CKP-C-41 ``Installation Instructions 
For 269 Series Helicopters, SA-269K-057-1 Main Rotor Thrust Bearing 
Kit,'' dated June 9, 1994.
    (d) This AD establishes a retirement life of 300 hours TIS for 
bearings, P/Ns 269A5050-50 and -51 and a retirement life of 3,000 
hours TIS for bearing, P/N 2695050-73. However, bearings, P/Ns 
269A5050-50 and -51, with at least 275 hours TIS but less than 300 
hours TIS on the effective date of this AD, need not be retired 
until or before the accumulation of an additional 25 hours TIS after 
the effective date of this AD.
    (e) Inspect the thrust bearing nut (nut), P/N 269A1306-5, for 
corrosion and physical damage and determine whether the nut has been 
modified in accordance with Step III of SSN No. N-59, dated October 
9, 1968.
    (1) If corrosion or physical damage is found, replace the nut 
with an airworthy nut that has been modified in accordance with Step 
III of SSN No. N-59, dated October 9, 1968.
    (2) If the nut has not been modified, modify the nut in 
accordance with Step III of SSN No. N-59, dated October 9, 1968.
    (f) Inspect the interior of the main rotor mast (mast) for 
corrosion, physical damage, foreign materials, moisture or 
inadequate drainage due to a buildup of zinc chromate paste and 
determine whether the mast has been modified in accordance with Step 
II of SSN No. N-59, dated October 9, 1968 to install a drain hole.
    (1) If corrosion or physical damage is found, replace the mast 
with an airworthy mast that has been modified in accordance with 
Step III of SSN No. N-59, dated October 9, 1968.
    (2) If the interior of the mast has foreign materials, moisture 
or inadequate drainage due to a buildup of zinc chromate past, clean 
the area with a suitable solvent in accordance with Step II of SSN 
No. N-59, dated October 9, 1968.
    (3) If the mast has not been modified, modify the mast in 
accordance with Step III of SSN No. N-59, dated October 9, 1968.
    (g) 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, New York Aircraft Certification 
Office. 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 2: 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.

    (h) 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 June 6, 1996.
Larry M. Kelly,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 96-15214 Filed 6-14-96; 8:45 am]
BILLING CODE 4910-13-M