DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2015-0365; Directorate Identifier 2014-SW-049-AD;
Amendment 39-18106; AD 2015-04-04]
RIN 2120-AA64

Airworthiness Directives; Bell Helicopter Textron Inc.
Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

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

SUMMARY: We are adopting a new airworthiness directive (AD) for Bell
Helicopter Textron Inc. (Bell) Model 412 and 412EP helicopters with
certain static inverters (inverters) installed. This AD requires
revising the Rotorcraft Flight Manual (RFM) and installing a placard in
full view of the pilot to limit flight to visual flight rules (VFR)
only and prohibit night operations. This AD is prompted by failures of
certain inverters, most of which resulted in smoke in the cockpit. The
actions specified by this AD are intended to restrict flight to VFR
only and prohibit night operations to allow safe operation in the event
of failure of an affected inverter. This failure would increase pilot
workload during instrument flight rules (IFR) and could result in loss
of certain pilot information displays and subsequent loss of control of
the helicopter.

DATES: This AD becomes effective March 11, 2015.
We must receive comments on this AD by April 27, 2015.

ADDRESSES: You may send comments by any of the following methods:
Federal eRulemaking Docket: Go to http://www.regulations.gov. Follow the
online instructions for sending your comments electronically.
Fax: 202-493-2251.
Mail: Send comments to the U.S. Department of
Transportation, Docket Operations, M-30, West Building Ground Floor,
Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590-0001.
Hand Delivery: Deliver to the ``Mail'' address between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov
or in person at the Docket Operations Office
between 9 a.m. and 5 p.m., Monday through Friday, except Federal
holidays. The AD docket contains this AD, the economic evaluation, any
comments received, and other information. The street address for the
Docket Operations Office (telephone 800-647-5527) is in the ADDRESSES
section. Comments will be available in the AD docket shortly after
receipt.
For service information identified in this AD, contact Bell
Helicopter Textron, Inc., P.O. Box 482, Fort Worth, TX 76101; telephone
(817) 280-3391; fax (817) 280-6466; or at http://www.bellcustomer.com/files/.
You may review the referenced service information at the FAA,
Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd.,
Room 663, Fort Worth, Texas 76137.

FOR FURTHER INFORMATION CONTACT: Ife Ogunleye, Aviation Safety
Engineer, Rotorcraft Certification Office, Rotorcraft Directorate, FAA,
2601 Meacham Blvd., Fort Worth, Texas 76137; telephone (817) 222-5927;
email 7-AVS-ASW-170@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

This AD is a final rule that involves requirements affecting flight
safety, and we did not provide you with notice and an opportunity to
provide your comments prior to it becoming effective. However, we
invite you to participate in this rulemaking by submitting written
comments, data, or views. We also invite comments relating to the
economic, environmental, energy, or federalism impacts that resulted
from adopting this AD. The most helpful comments reference a specific
portion of the AD, explain the reason for any recommended change, and
include supporting data. To ensure the docket does not contain
duplicate comments, commenters should send only one copy of written
comments, or if comments are filed electronically, commenters should
submit them only one time. We will file in the docket all comments that
we receive, as well as a report summarizing each substantive public
contact with FAA personnel concerning this rulemaking during the
comment period. We will consider all the comments we receive and may
conduct additional rulemaking based on those comments.

Discussion

We are adopting a new AD for Bell Model 412 and 412EP helicopters
with an inverter part number (P/N) 412-375-079-101 or P/N 412-375-079-
103 with a serial number 29145 or larger. This AD limits operations to
VFR and prohibits night operations by adding a restriction to the RFM
and installing a placard in full view of the pilots. This AD is
prompted by at least 30 failures of certain inverters; most have
resulted in smoke in the cockpit. The root cause of the failures is
still under investigation by Bell and Avionics Instruments LLC, the
manufacturer of the inverters. The consequence of one failed inverter
has the potential of allowing smoke in the cockpit, making it difficult
to find a safe landing site at night or in instrument meteorological
conditions. If both inverters fail, the pilot will lose primary flight
and navigation displays, alternating current powered engine and
transmission indicators, and autopilot. The RFM emergency procedure for
dual inverter failure is to land as soon as practicable or fly VFR. The
RFM emergency procedure for smoke in the cabin is to land as soon as
possible. Until a new design is available, restricting flight
operations to VFR and daytime increases the likelihood of a prompt safe
landing.

FAA's Determination

We are issuing this AD because we evaluated all the relevant
information and determined the unsafe condition described previously is
likely to exist or develop in other products of these same type
designs.

Related Service Information

Bell issued Alert Service Bulletin 412-13-156, dated April 25, 2013
(ASB), which specifies inspecting part-numbered 412-375-079-101
inverters and either repairing each inverter or replacing it with
inverter P/N 412-375-079-103 to prevent failure. This ASB does not
correct the unsafe condition identified in this AD. The specific cause
of the inverter failures has not been verified, and since Bell issued
the ASB, the failures have continued.

AD Requirements

This AD requires, within 5 hours time-in-service, limiting
operations to VFR and prohibiting night operations by revising the
Limitations section of the RFM and by installing a placard in the
cockpit in full view of the pilots.

Interim Action

We consider this AD to be an interim action. The design approval
holder is currently developing a modification that will address the
unsafe condition identified in this AD. Once this modification is
developed, approved, and available, we might consider additional
rulemaking.

Costs of Compliance

We estimate that this AD will affect 88 helicopters of U.S.
Registry.
We estimate that operators may incur the following costs in order
to comply with this AD. Labor costs are $85 per work hour. We estimate
a minimal amount of time to revise the RFM and to install a placard.
The required parts are $10 for a placard. Based on these requirements,
the cost will be $10 per helicopter and $880 for the U.S. fleet.

FAA's Justification and Determination of the Effective Date

Providing an opportunity for public comments before adopting these
AD requirements would delay implementing the safety actions needed to
correct this known unsafe condition. Therefore, we find that the risk
to the flying public justifies waiving notice and comment before
adopting this rule because the required corrective actions must be done
within 5 hours time-in-service.
Since an unsafe condition exists that requires the immediate
adoption of this AD, we determined that notice and opportunity for
public comment before issuing this AD are impracticable and contrary to
the public interest and that good cause exists for making this
amendment effective in less than 30 days.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. Subtitle I, section 106, describes the
authority of the FAA Administrator. ``Subtitle VII: Aviation
Programs,'' describes in more detail the scope of the Agency's
authority.
We are issuing this rulemaking under the authority described in
``Subtitle VII, Part A, Subpart III, Section 44701: General
requirements.'' Under that section, Congress charges the FAA with
promoting safe flight of civil aircraft in air commerce by prescribing
regulations for practices, methods, and procedures the Administrator
finds necessary for safety in air commerce. This regulation is within
the scope of that authority because it addresses an unsafe condition
that is likely to exist or develop on products identified in this
rulemaking action.

Regulatory Findings

We determined that this AD will not have federalism implications
under Executive Order 13132. This AD will not have a substantial direct
effect 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.
For the reasons discussed, I certify that this AD:
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);
3. Will not affect intrastate aviation in Alaska to the extent that
it justifies making a regulatory distinction; and
4. 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.
We prepared an economic evaluation of the estimated costs to comply
with this AD and placed it in the AD docket.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by
Reference, Safety.

Adoption of the Amendment

Accordingly, under the authority delegated to me by the
Administrator, the FAA amends 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. The FAA amends Sec. 39.13 by adding the following new airworthiness
directive (AD):