This section of the FEDERAL REGISTER

contains regulatory documents having general

applicability and legal effect, most of which

are keyed to and codified in the Code of

Federal Regulations, which is published under

50 titles pursuant to 44 U.S.C. 1510.

The Code of Federal Regulations is sold by

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new books are listed in the first FEDERAL

REGISTER issue of each week.

Rules and Regulations Federal Register

69177

Vol. 63, No. 241

Wednesday, December 16, 1998

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96–SW–29–AD; Amendment

39–10943; AD 98–26–02]

Airworthiness Directives; Sikorsky

Aircraft Corporation Model S–61A, D,

E, L, N, NM, R, and V Helicopters

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Final rule.

SUMMARY: This amendment adopts a

new airworthiness directive (AD),

applicable to Sikorsky Aircraft

Corporation Model S–61A, D, E, L, N,

NM, R, and V helicopters, that requires

a nondestructive inspection (NDI) for

cracks in the main rotor shaft (shaft),

and requires removal of any shaft with

a crack and replacement with an

airworthy shaft. This AD also requires

appropriate marking of shafts and log

book entries by the operator to

determine the shaft retirement life, and

establishes a new retirement life for the

shaft. This amendment is prompted by

four reports of cracks occurring in

helicopters that were utilized in

repetitive external lift (REL) operations.

The actions specified by this AD are

intended to detect a fatigue crack in the

shaft that could result in shaft structural

failure, loss of power to the main rotor,

and subsequent loss of control of the

helicopter.

DATES: Effective January 20, 1999.

The incorporation by reference of

certain publications listed in the

regulations is approved by the Director

of the Federal Register as of January 20,

1999.

ADDRESSES: The service information

referenced in this AD may be obtained

from Sikorsky Aircraft Corporation,

Attn: Manager, Commercial Tech

Support, 6900 Main Street, P.O. Box

9729, Stratford, CT 06497–9129. This

information may be examined at the

FAA, Office of the Regional Counsel,

Southwest Region, 2601 Meacham

Blvd., Room 663, Fort Worth, Texas

76137; or at the Office of the Federal

Register, 800 North Capitol Street, NW.,

suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Wayne Gualzetti, Aerospace Engineer,

ANE–150, 12 New England Executive

Park, Burlington, MA 01803, telephone

(781) 238–7156, fax (781) 238–7199.

SUPPLEMENTARY INFORMATION: A

proposal to amend part 39 of the Federal

Aviation Regulations (14 CFR part 39) to

include an airworthiness directive (AD)

that is applicable to Sikorsky Aircraft

Corporation Model S–61A, D, E, L, N,

NM, R, and V helicopters was published

in the Federal Register on September

18, 1997 (62 FR 48961). That action

proposed to require a NDI of the shaft,

part number (P/N) S6135–20640–001,

S6135–20640–002, or S6137–23040–

001, used in REL operations within the

next 1,000 hours time-in-service (TIS).

The NDI must be performed in

accordance with the Overhaul Manual.

That action also proposed to establish

retirement lives for certain shafts

utilized in REL operations. For shafts

installed on helicopters utilized in REL

operations that have not been modified

in accordance with Sikorsky Customer

Service Notice (CSN) 6135–10, dated

March 18, 1987, and Sikorsky Alert

Service Bulletin (ASB) No. 61B35–53,

dated December 2, 1981, the retirement

life would be 1,500 hours TIS. For shafts

installed on helicopters utilized in REL

operations that have been modified in

accordance with Sikorsky CSN 6135–10,

dated March 18, 1987, and Sikorsky

ASB No. 61B35–53, dated December 2,

1981, the retirement life would be 2,000

hours TIS.

Interested persons have been afforded

an opportunity to participate in the

making of this amendment. Due

consideration has been given to the

comments received.

Several commenters state that the cost

of a replacement shaft, which is

$44,753, should be stated in the AD to

indicate the severity of the cost impact

this AD will have on owners and

operators. The FAA concurs and will

include the cost of the shaft in the AD.

One commenter states that issuance of

the AD is unnecessary because, over a

period of 38 years, there have been only

two occurrences of shaft cracks. The

FAA does not concur. There have been

a total of four reported instances of

cracked shaft flanges. All four shafts

were used in REL operations.

Subsequent tests conducted by the

manufacturer confirmed the failure due

to REL cycles and the need for the life

limitation.

The same commenter states that the

AD should be applicable to Model CH–

3C, CH–3E, HH–3C, and HH–3E

helicopters. The FAA concurs since

these restricted category helicopters are

equipped with the same main gearbox

and shaft. These models will be the

subject of future rulemaking action.

Two commenters state that the

proposed retirement life should be

increased from 2,000 hours TIS to 2,500

hours TIS. The change is requested so

that the shaft retirement time will be in

line with existing gearbox overhaul

requirements. The FAA partially

concurs. This change will allow the

shaft replacement to be conducted

concurrently with any recommended

gearbox overhaul actions. Based on a

further evaluation of the dowel pin

cracking and the fretting cracking, the

FAA has determined that the retirement

life can safely be increased from the

proposed 2,000 hours TIS to 2,200 hours

TIS. This will allow operators to get two

overhaul cycles of 1,100 hours TIS for

each shaft used in REL operations.

Therefore, the retirement life is

extended from 2,000 hours TIS to 2,200

hours TIS for shafts that have been

modified in accordance with the

Sikorsky service information described

previously. This change also will allow

operators to avoid excessive

disassembly and re-assembly of the

gearbox for overhauls and shaft removal

based on an approved 1,100 hours TIS

gearbox overhaul cycle.

After careful review of the available

data, including the comments noted

above, the FAA has determined that air

safety and the public interest require the

adoption of the rule with the changes

described previously. 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 30 helicopters

of U.S. registry that are involved in REL

operations will be affected by this AD,

that it will take approximately 2.2 work

hours per helicopter to accomplish the
69178 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

required actions during the next

scheduled overhaul, and that the

average labor rate is $60 per work hour.

Required parts will cost approximately

$50 for the inspection and $44,753 for

each shaft. Based on these figures, the

total cost impact of the AD on U.S.

operators is estimated to be $1,348,050,

assuming all 30 shafts are replaced.

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. 106(g), 40113, 44701.

§ 39.13 [Amended]

2. Section 39.13 is amended by

adding a new airworthiness directive to

read as follows:

AD 98–26–02 Sikorsky Aircraft

Corporation: Amendment 39–10943.

Docket No. 96–SW–29–AD.

Applicability: Model S–61A, D, E, L, N,

NM, R, and V helicopters, with main rotor

shaft (shaft), part number (P/N) S6135–

20640–001, S6135–20640–002, or S6137–

23040–001, 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 (e) 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 change 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 detect a fatigue crack in the shaft that

could result in shaft structural failure, loss of

power to the main rotor, and subsequent loss

of control of the helicopter, accomplish the

following:

(a) Within the next 30 calendar days or 240

hours time-in-service (TIS) after the effective

date of this AD, whichever occurs first,

determine if the shaft has been used in

repetitive external lift (REL) operations. REL

operation is defined as operation during

which the average number of external lifts

equals or exceeds six per flight hour for any

250 hour TIS period during the main gearbox

overhaul interval. An external lift is defined

as a flight cycle in which an external load is

picked up, the helicopter is repositioned

(through flight or hover), and the helicopter

hovers and releases the load and departs or

lands and departs. Record the total number

of hours TIS during which external lifts have

been conducted, as well as the number of

external lifts conducted during each hour, on

the component log card or equivalent record.

If the number of external lifts cannot be

determined, assume 6 external lifts were

conducted during each hour TIS in which

external lifts were conducted. If the hours

TIS of external lift operations cannot be

determined, assume REL operations were

conducted.

(b) For shafts used in REL operations,

within the next 1,100 hours TIS after the

effective date of this AD, conduct a nondestructive inspection (NDI) for cracks in the

shaft in accordance with the Overhaul

Manual. If a crack is discovered in a shaft,

remove the shaft and replace it with an

airworthy shaft. Mark the removed airworthy

shafts and the replacement shafts in

accordance with the Accomplishment

Instructions in paragraphs 2E and 2f of

Sikorsky Aircraft Corporation Alert Service

Bulletin (ASB) No. 61B35–68, dated July 19,

1996. Once a shaft has been designated and

marked as an REL shaft, it is life-limited

accordingly for the remainder of that shaft’s

airworthy service life.

(c) Retire all shafts that have been used in

REL operations as follows:

(1) Shafts that have been modified in

accordance with Sikorsky Customer Service

Notice 6135–10, dated March 18, 1997, and

Sikorsky ASB No. 61B35–53, dated December

2, 1981 (modified REL shafts), must be

removed from service on or before attaining

2,200 hours TIS.

(2) Shafts that have not been modified in

accordance with Sikorsky Customer Service

Notice 6135–10, dated March 18, 1987, and

Sikorsky ASB 61B35–53, dated December

1981 (unmodified REL shafts), must be

removed from service on or before attaining

1,500 hours TIS.

(d) This AD revises the Limitations section

of the maintenance manual by establishing

new retirement lives of 1,500 hours TIS for

unmodified REL shafts and 2,200 hours TIS

for modified REL shafts.

(e) 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, Boston

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, Boston 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 Boston Aircraft

Certification Office.

(f) 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.

(g) The marking of the shaft shall be done

in accordance with Sikorsky Aircraft

Corporation Alert Service Bulletin No.

61B35–68, dated July 19, 1996. 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

Sikorsky Aircraft Corporation, Attn: Manager,

Commercial Tech Support, 6900 Main Street,

P.O. Box 9729, Stratford, CT 06497–9129.

Copies may be inspected at the FAA, Office

of the Regional Counsel, Southwest Region,

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.

(h) This amendment becomes effective on

January 20, 1999.

Issued in Forth Worth, Texas, on December

7, 1998.

Henry A. Armstrong,

Manager, Rotorcraft Directorate, Aircraft

Certification Service.

[FR Doc. 98–33106 Filed 12–15–98; 8:45 am]

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