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

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 94-SW-17-AD; Amendment 39-9950; AD 97-05-06]

RIN 2120-AA64

Airworthiness Directives; Schweizer Aircraft Corporation and

Hughes Helicopters, Inc. Model 269A, 269A-1, 269B, and TH-55A

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, 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 amendment requires 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 amendment is prompted by an FAA

analysis of service information issued by the manufacturer that extends

the retirement life for certain bearings. The actions specified by this

AD are intended to prevent failure of the bearing, loss of the main

rotor, and subsequent loss of control of the helicopter.

DATES: Effective April 7, 1997.

The incorporation by reference of certain publications listed in

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

of April 7, 1997.

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 FAA, Office of the

Assistant Chief Counsel, Room 663, 2601 Meacham Blvd., 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. 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: A proposal to amend part 39 of the Federal

Aviation Regulations (14 CFR part 39) by superseding AD 68-21-05,

Amendment 39-672 (33 FR 15543, October 19, 1968), which is applicable

to 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, as revised by Amendment 39-1055 (35 FR 12532, August

6, 1970), was published in the Federal Register on June 17, 1996 (61 FR

30548). That action proposed to require the same initial and repetitive

inspections required by the existing AD (inspections of the main rotor

thrust bearing (bearing) for bearing rotational roughness, corrosion,

inadequate lubrication, physical damage, or excessive zinc chromate

paste or moisture), 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.

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, except for editorial changes and

changes to paragraph (a) that more specifically state the actions that

are required for those bearings having less than 300 hours time-in-

service. The FAA has determined that these changes will neither

increase the economic burden on any operator nor expand the scope of

the AD.

The FAA estimates that 500 helicopters of U.S. registry will be

affected by this AD, that it will take approximately 8 work hours per

helicopter to accomplish the required

[[Page 9362]]

actions, and that the average labor rate is $60 per work hour. Required

parts will cost approximately $1,890 per helicopter. Based on these

figures, the total cost impact of the AD on U.S. operators is estimated

to be $1,185,000.

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. 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), Amendment 39-

9950, to read as follows:

AD 97-05-06 SCHWEIZER AIRCRAFT CORPORATION AND HUGHES HELICOPTERS,

INC.: Amendment 39-9950. 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, 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 (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 (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 bearing, part number (P/N) 269A5050-50, P/N 269A5050-51,

or P/N 269A5050-73.

(1) If the TIS on the bearing, P/N 269A5050-50 or -51, equals or

exceeds 300 hours TIS, replace the bearing with an airworthy bearing

before further flight.

(2) If the TIS on the bearing, P/N 269A5050-50 or -51, equals or

exceeds 275 hours TIS, and is less than 300 hours TIS, replace the

bearing with an airworthy bearing within the next 25 hours TIS.

(3) If the TIS on the bearing, P/N 269A5050-50 or -51, is less

than 275 hours TIS, replace the bearing with an airworthy bearing on

or before 300 hours TIS.

(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, need not be retired until or before the accumulation of

an additional 25 hours TIS.

(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 paste,

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

[[Page 9363]]

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.

(i) The inspections, modifications, and replacements shall be

done in accordance with Schweizer Service Notice No. N-59, dated

October 9, 1968 and 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. 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, Room 663, 2601 Meacham Blvd.,

Fort Worth, Texas; or at the Office of the Federal Register, 800

North Capitol Street, NW., suite 700, Washington, DC.

(j) This amendment becomes effective on April 7, 1997.

Issued in Fort Worth, Texas, on February 20, 1997.

Eric Bries,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.

[FR Doc. 97-4951 Filed 2-28-97; 8:45 am]

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