Airworthiness Directives; Bell Helicopter Textron, Inc. Model 412 Helicopters and Agusta S.p.A. Model AB412 Helicopters

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-SW-58-AD; Amendment 39-10421; AD 98-07-03]

RIN 2120-AA64

Airworthiness Directives; Bell Helicopter Textron, Inc. Model 412

Helicopters and Agusta S.p.A. Model AB412 Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

-----------------------------------------------------------------------

SUMMARY: This amendment adopts a new airworthiness directive (AD) that

is applicable to Bell Helicopter Textron, Inc. (Bell) Model 412

helicopters and Agusta S.p.A. (Agusta) Model AB412 helicopters. This

action requires a temporary reduction of the never-exceed velocity

(Vne) limitation until an inspection of the tail rotor yoke (yoke)

assembly for fatigue damage and installation of a redesigned yoke

flapping stop are accomplished. Recurring periodic and special

inspections to detect occurrences of yoke overload are also required.

This amendment is prompted by laboratory tests and engineering analyses

that indicated that the yoke assembly is susceptible to fatigue damage

due to unforeseen static and dynamic loading of the tail rotor against

the original flapping stop. The actions specified in this AD are

intended to prevent fatigue failure of the yoke that could result in

loss of control of the tail rotor and subsequent loss of control of the

helicopter.

DATES: Effective April 8, 1998.

The incorporation by reference of certain publications listed in

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

of April 8, 1998.

Comments for inclusion in the Rules Docket must be received on or

before May 26, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Office of the Regional Counsel, Southwest Region,

Attention: Rules Docket No. 97-SW-58-AD, 2601 Meacham Blvd., Room 663,

Fort Worth, Texas 76137.

The service information referenced in this AD may be obtained from

Bell Helicopter Textron, Inc., P.O. Box 482, Fort Worth, Texas 76101,

telephone (817) 280-3391, fax (817) 280-6466 for the Bell Model 412

helicopters; and

[[Page 14027]]

Agusta S.p.A., 21017 Cascina Costa di Samarate (VA), Via Giovanni

Agusta 520, telephone (0331) 229111, fax (0331) 229605-222595 for the

Agusta Model AB412 helicopters. This information may be examined 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.

FOR FURTHER INFORMATION CONTACT: Mr. Shep Blackman, Aerospace Engineer,

FAA, Rotorcraft Directorate, Rotorcraft Standards Staff, 2601 Meacham

Blvd., Fort Worth, Texas 76137, telephone (817) 222-5296, fax (817)

222-5961.

SUPPLEMENTARY INFORMATION: The Registro Aeronautico Italiano (RAI),

which is the airworthiness authority for Italy, recently notified the

FAA that an unsafe condition may exist on Agusta Model AB412

helicopters, and since the Bell Model 412 helicopters are of similar

type design, a similar unsafe condition could exist on those models.

The RAI advises installing a temporary airspeed placard, inspecting the

yoke assembly, and installing a redesigned tail rotor flapping stop.

Bell has issued Bell Helicopter Textron Alert Service Bulletin

(ASB) 412-96-89, Revision A, dated October 17, 1997 and Bell Helicopter

Textron ASB 412CF-96-01, dated September 3, 1996, for the Bell Model

412 helicopters; and Agusta has issued Agusta Bolletino Tecnico

(Technical Bulletin) No. 412-65, dated December 2, 1996 for the Agusta

Model AB412 helicopters. Both service bulletins and the technical

bulletin specify an immediate temporary reduction in the maximum

airspeed, installing a cockpit placard for this limitation, and

incorporating a temporary flight manual supplement until the yoke

historical records are researched for previous damage history; until an

x-ray diffraction inspection is performed on the yoke to detect fatigue

damage; and until a frangible tail rotor flapping stop/yield indicator,

P/N 212-011-713-103, is installed. A repetitive 25-hours time-in-

service inspection to detect damaging tail rotor flapping stop contact

due to a hard landing, sudden stoppage, or miscellaneous power on/off

incidents has been added. The RAI classified the Agusta technical

bulletin as mandatory and issued AD 97-223 in order to assure the

continued airworthiness of these helicopters in Italy.

The Bell Model 412 helicopters are manufactured in the U.S. and are

type certificated for operation in the United States under the

provisions of Sec. 21.21 of the Federal Aviation Regulations (14 CFR

21.21). The Agusta Model AB412 helicopters are manufactured in Italy

and are type certificated for operation in the United States under the

provisions of Sec. 21.29 of the Federal Aviation Regulations (14 CFR

21.29) and the applicable bilateral airworthiness agreement. Pursuant

to this bilateral airworthiness agreement, the RAI has kept the FAA

informed of the situation described above. The FAA has examined the

findings of the RAI, reviewed all available information, and determined

that AD action is necessary for products of these type designs that are

certificated for operation in the United States.

Since an unsafe condition has been identified that is likely to

exist or develop on other Bell Model 412 and Agusta Model AB412

helicopters of the same type designs registered or eligible for

registration in the United States, this AD is being issued to prevent

fatigue failure of the yoke that could result in loss of control of the

helicopter. This AD requires a temporary reduction of the Vne

limitation until an inspection of the yoke assembly for fatigue damage

and installation of a redesigned yoke flapping stop is accomplished,

and includes additional periodic and special inspections to detect

occurrences of yoke overload.

The short compliance time involved is required because the

previously described critical unsafe condition can adversely affect the

controllability of the helicopter. Therefore, a temporary reduction in

Vne is required prior to further flight, and this AD must be issued

immediately.

Since a situation exists that requires the immediate adoption of

this regulation, it is found that notice and opportunity for prior

public comment hereon are impracticable, and that good cause exists for

making this amendment effective in less than 30 days.

The FAA estimates that 124 helicopters of U.S. registry will be

affected by this AD, that it will take approximately 6.5 hours per

helicopter to accomplish the installation of a placard, the inspection,

and the installation of the yoke. Required parts will cost

approximately $511 per helicopter. Based on these figures, the total

cost impact of this AD on U.S. operators is estimated to be $111,724.

Comments Invited

Although this action is in the form of a final rule that involves

requirements affecting flight safety and, thus, was not preceded by

notice and an opportunity for public comment, comments are invited on

this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All

communications received on or before the closing date for comments will

be considered, and this rule may be amended in light of the comments

received. Factual information that supports the commenter's ideas and

suggestions is extremely helpful in evaluating the effectiveness of the

AD action and determining whether additional rulemaking action would be

needed.

Comments are specifically invited on the overall regulatory,

economic, environmental, and energy aspects of the rule that might

suggest a need to modify the 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 that

summarizes each FAA-public contact concerned with the substance of this

AD will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments

submitted in response to this rule must submit a self-addressed,

stamped postcard on which the following statement is made: ``Comments

to Docket No. 97-SW-58-AD.'' The postcard will be date stamped and

returned to the commenter.

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.

The FAA has determined that this regulation is an emergency

regulation that must be issued immediately to correct an unsafe

condition in aircraft, and that it is not a ``significant regulatory

action'' under Executive Order 12866. It has been determined further

that this action involves an emergency regulation under DOT Regulatory

Policies and Procedures (44 FR 11034, February 26, 1979). If it is

determined that this emergency regulation otherwise would be

significant under DOT Regulatory Policies and Procedures, a final

regulatory evaluation will be prepared and placed in the Rules Docket.

A copy of it, if filed, may be obtained from the

[[Page 14028]]

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.

Sec. 39.13 [Amended]

2. Section 39.13 is amended by adding a new airworthiness directive

to read as follows:

AD 98-07-03 Bell Helicopter Textron, Inc. and Agusta S.p.A.:

Amendment 39-10421. Docket No. 97-SW-58-AD.

Applicability: Bell Helicopter Textron, Inc. Model 412

helicopters, serial numbers (S/N) 33001 through 33213, 34001 through

34024, 36001 through 36121, 46400 through 46434, 46437, and Agusta

S.p.A. Model AB412 helicopters, S/N prior to and including S/N

25806, and S/N 25901; 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 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 fatigue failure of the tail rotor yoke (yoke), that

could result in loss of control of the helicopter, accomplish the

following:

(a) Before further flight, review the historical records of the

yoke assembly, part number (P/N) 212-011-702-all dash numbers, for

any static or dynamic incident history, other than normal usage,

that could have imposed a bending load on the yoke, but did not

require yoke assembly replacement; for example, an incident in which

a damaged tail rotor blade was replaced due to a blade strike. If

such a history exists, replace the yoke with an airworthy yoke.

(b) Before further flight, unless paragraph (c) of this AD has

been accomplished previously:

(1) Install a Never Exceed Velocity (Vne) red line at 120 knots

indicated airspeed (KIAS) on the pilot and copilot airspeed

indicators using red tape or paint, and a slippage indicator on the

instrument case and glass.

(2) Install a placard made of material that is not easily

erased, disfigured, or obscured on the instrument panel in clear

view of the pilot and copilot: ``Observe temporary Maximum Never

Exceed (Vne) airspeed red line (marked at 120 knots indicated

airspeed (KIAS)). Vne is 20 KIAS less than the value presented on

the airspeed limitation placard for each ambient condition.''

(3) Insert the applicable Bell Helicopter Textron 412 Temporary

Revision, dated August 16, 1996, into the Model 412 Rotorcraft

Flight Manual (RFM), or Agusta AB412EP Temporary Revision No. 2 into

the Model AB412 RFM.

(c) Within 180 calendar days:

(1) Remove yoke assembly, P/N 212-011-702-all dash numbers, and

replace it with an airworthy yoke assembly, P/N 212-011-702-all dash

numbers, with zero hours time-in-service (TIS), or an airworthy yoke

(regardless of TIS) that has passed a one-time x-ray diffraction

inspection in accordance with Bell Helicopter Textron ASB 412-96-89,

Revision A, dated October 17, 1997; Bell Helicopter Textron ASB

412CF-96-01, dated September 3, 1996; or, Agusta Bolletino Tecnico

(Technical Bulletin) No. 412-65, dated December 2, 1996, whichever

is applicable.

(2) Install an airworthy tail rotor flapping stop, P/N 212-011-

713-103.

(3) If requirements are accomplished in accordance with paragraphs

(c)(1) and (c)(2) of this AD, remove the 120 KIAS redline from the

pilot and copilot airspeed indicators; remove the Vne airspeed

restriction placard; and remove the Bell Helicopter Textron 412

Temporary Revision, dated August 16, 1996, or Agusta AB Temporary

Revision No. 2, as applicable, from the RFM.

(d) After accomplishing paragraph (c) of this AD, thereafter

inspect the yoke assembly and tail rotor flapping stop at intervals

not to exceed 25 hours TIS in accordance with Part III, Recurring

25-Hour Special Inspection and Conditional Inspection Requirement,

of Bell Helicopter Textron ASB 412-96-89, Revision A, dated October

17, 1996; Bell Helicopter Textron ASB 412CF-96-01, dated September

3, 1996; or Agusta Bolletino Tecnico (Technical Bulletin) No. 412-

65, dated December 2, 1996, as applicable.

(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, Rotorcraft Standards Staff,

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 Standards Staff.

Note 2: Information concerning the existence of approved

alternative methods of compliance with this AD, if any, may be

obtained from the Rotorcraft Standards Staff.

(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 at airspeeds not to

exceed 120 KIAS to a location where the requirements of this AD can

be accomplished.

(g) The inspections and installations shall be done in

accordance with Bell ASB 412-96-89, Revision A, dated October 17,

1997; Bell Helicopter Textron ASB 412CF-96-01, dated September 3,

1996; or Agusta Technical Bulletin No. 412-65, dated December 2,

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 Bell Helicopter Textron, Inc.,

P.O. Box 482, Fort Worth, Texas 76101, telephone (817) 280-3391, fax

(817) 280-6466; or Agusta, 21017 Cascina Costa di Samarate (VA), Via

Giovanni Agusta 520, telephone (0331) 229111, fax (0331) 229605-

222595. 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 April 8, 1998.

Note 3: The subject of this AD is addressed in Registro

Aeronautico Italiano (Italy) AD 97-223, dated January 8, 1997.

Issued in Fort Worth, Texas, on March 16, 1998.

Eric Bries,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.

[FR Doc. 98-7414 Filed 3-23-98; 8:45 am]

BILLING CODE 4910-13-U