[Federal Register Volume 63, Number 56 (Tuesday, March 24, 1998)]
[Rules and Regulations]
[Pages 14026-14028]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-7414]


=======================================================================
-----------------------------------------------------------------------

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