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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 92-ASW-50; Amendment 39-8934; AD 94-12-06]

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: Final rule.

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SUMMARY: This amendment supersedes 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, that currently requires repetitive inspections and

replacement of certain lower belt drive pulley bearings (pulley

bearings). This amendment retains the present AD requirements and adds

an alternate pulley bearing to the requirements of the AD. This

amendment is prompted by the introduction of an alternate pulley

bearing into service by Schweizer Aircraft Corporation. The actions

specified by this AD are intended to prevent failure of the pulley

bearings, loss of power to the rotor systems, and subsequent loss of

control of the helicopter.

DATES: Effective on September 19, 1994.

The incorporation by reference of certain publications listed in

the regulations is approved by the Director of the Federal Register as

of September 19, 1994.

ADDRESSES: The service information referenced in this AD may be

obtained from Schweizer Aircraft Corporation, P.O. Box 147, Elmira, New

York 14902. This information may be examined at the Federal Aviation

Administration (FAA), Office of the Assistant Chief Counsel, 2601

Meacham Blvd., room 663, Fort Worth, Texas; or at the Office of the

Federal Register, 800 North Capitol Street NW., suite 700, Washington,

DC.

FOR FURTHER INFORMATION CONTACT: Mr. Raymond Reinhardt, Aerospace

Engineer, FAA, New York Aircraft Certification Office, Propulsion

Branch, ANE-174, New England Region, 181 South Franklin Avenue, Valley

Stream, New York 11581, telephone (516) 791-7421, fax (516) 791-9024.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal

Aviation Regulations (14 CFR 39) by superseding AD 80-02-14, Amendment

39-3668 (45 FR 3251, January 17, 1980), which is applicable to

Schweizer Aircraft Corporation and Hughes Helicopters, Inc. Model 269A,

269A-1, 269B, 269C, and TH-55A series helicopters, was published in the

Federal Register on July 2, 1993 (58 FR 35900). That action proposed to

continue the present AD requirements for lower belt drive pulley

bearings (pulley bearings), part number (P/N) 269A5050-57, and also

proposed a one-time inspection of the pulley bearing installation,

repetitive inspections of the pulley bearings, and an 1,800 hours'

time-in-service life limit for pulley bearings, part number (P/N)

269A5050-80. Pulley bearings, P/N 269A5050-80, are subject to the same

requirements as pulley bearings, P/N 269A5050-57.

Interested persons have been afforded an opportunity to participate

in the making of this amendment. No comments were received on the

proposal or the FAA's determination of the cost to the public. The FAA

has determined that air safety and the public interest require the

adoption of the rule as proposed, with only editorial changes. The FAA

has determined that these changes will neither increase the economic

burden on any operator nor increase the scope of the AD.

The FAA estimates that 700 helicopters of U.S. registry will be

affected by this AD, that it will take approximately 1.5 work hours per

helicopter to accomplish the required actions, and that the average

labor rate is $55 per work hour. Required parts, if needed, will cost

approximately $635 per helicopter. Based on these figures, the total

cost impact of the AD on U.S. operators is estimated to be $168,875

each year assuming 175 helicopters would need new parts each year.

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.

For the reasons discussed above, I certify that this action (1) is

not a ``significant regulatory action'' under Executive Order 12866;

(2) is not a ``significant rule'' under DOT Regulatory Policies and

Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action

and it is contained in the Rules Docket. A copy of it 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, Incorporation by

reference, 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. 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 39-3668, (45 FR

3251, January 17, 1980), and by adding a new airworthiness directive

(AD), Amendment 39-8934, to read as follows:

94-12-06 Schweizer Aircraft Corporation and Hughes Helicopters,

Inc.: Amendment 39-8934. Docket Number 92-ASW-50. Supersedes AD 80-

02-14, Amendment 39-3668.

Applicability: Model 269A, 269A-1, 269B, 269C, and TH-55A

helicopters, with lower belt drive pulley bearings, part number (P/

N) 269A5050-57 or 269A5050-80, installed, certificated in any

category.

Compliance: Required as indicated, unless accomplished

previously.

To prevent failure of the lower belt drive pulley bearings

(pulley bearings), loss of power to the rotor systems, and

subsequent loss of control of the helicopter, accomplish the

following:

(a) Within the next 50 hours' time-in-service (TIS) after the

effective date of this AD, replace all pulley bearings, P/N

269A5050-57 or 269A5050-80, that have accumulated 1,750 or more

hours' TIS on the effective date of this AD. For pulley bearings

that have accumulated less than 1,750 hours' TIS on the effective

date of this AD, replace these pulley bearings on or prior to

attaining 1,800 hours' total TIS. If replaced with pulley bearings,

P/N 269A5050-57 or 269A5050-80, the repetitive inspection

requirements of paragraph (d) of this AD are applicable.

Note: The following paragraphs of the AD, relative to bearing

retention system inspection, cover two systems of retention. At

delivery, all Model 269A, 269A-1, 269B, TH-55A, and certain 269C

helicopters, serial numbers 1 through 589, were equipped with sheet

metal lower bearing straps, P/N 269A5463. Model 269C helicopters,

serial numbers 590 and subsequent, were equipped with machined lower

bearing caps that are part of a 269A5573-11 ``H'' frame assembly.

Paragraph (b) concerns the sheet metal straps and paragraph (c)

concerns the machined caps.

(b) Within the next 50 hours' TIS after the effective date of

this AD, on helicopters equipped with sheet metal lower bearing

straps, P/N 269A5463--

(1) Inspect the pulley bearings in accordance with paragraphs a.

through f. of Part I of Schweizer Aircraft Corporation or Hughes

Helicopters, Inc. Service Information Notice (SIN) N-146.2, dated

December 7, 1979, and,

(2) Shim bearing straps in accordance with paragraph h.(2) of

Part I of SIN N-146.2, dated December 7, 1979.

(c) Within the next 50 hours' TIS after the effective date of

this AD, on helicopters equipped with machined lower pulley bearing

caps (caps) that are part of a 269A5573-11 ``H'' frame assembly,

inspect caps and frame assembly lower bearing bore for out-of-

roundness in accordance with paragraphs l. through p., Part I of SIN

N-164, dated December 7, 1979.

(1) If out-of-roundness exceeds 0.001 inch Total Indicator

Reading (T.I.R.), reverse the caps and repeat the inspections of

paragraph (c) of this AD for both caps.

(2) If out-of-roundness exceeds 0.001 inch T.I.R. after

reversing and reinspecting the caps, replace both caps with two

lower bearing straps, P/N 269A5463, in accordance with paragraph r.

of Part I of SIN N-164, dated December 7, 1979.

(d) Within 300 hours' TIS after accomplishing paragraphs (b) or

(c) of this AD, and thereafter at intervals not to exceed 300 hours'

TIS from the last inspection, inspect the pulley bearings in

accordance with paragraph a. through e. of Part III of SIN N-164,

dated December 7, 1979.

(e) Before returning any helicopter equipped with a replacement

``H'' frame assembly to service, accomplish the inspections of

paragraphs (b) or (c) of this AD as appropriate.

(f) 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.

(g) 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.

(h) The inspections and replacements shall be done in accordance

with Schweizer Aircraft Corporation SIN N-164 and SIN N-146.2, both

dated December 7, 1979. This incorporation by reference was approved

by the Director of the Federal Register in accordance with 5 U.S.C.

552(a) and 1 CFR Part 51. Copies may be obtained from Schweizer

Aircraft Corporation, P.O. Box 147, Elmira, New York 14902. Copies

may be inspected at the FAA, Office of the Assistant Chief Counsel,

2601 Meacham Blvd., Room 663, Fort Worth, Texas; or at the Office of

the Federal Register, 800 North Capitol Street NW., suite 700,

Washington, DC.

(i) This amendment becomes effective on September 19, 1994.

Issued in Fort Worth, Texas, on June 17, 1994.

Eric Bries,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.

[FR Doc. 94-17868 Filed 8-12-94; 8:45 am]

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