DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2018-0870; Product Identifier 2018-CE-047-AD; Amendment
39-19438; AD 2018-20-04]
RIN 2120-AA64

Airworthiness Directives; Gulfstream Aerospace Corporation Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

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SUMMARY: We are adopting a new airworthiness directive (AD) for all
Gulfstream Aerospace Corporation (Gulfstream) Model GVI airplanes. This
AD requires revising the Normal and Abnormal Procedures sections of the
airplane flight manual (AFM). This AD was prompted by potential failure
of the bi-directional data bus that sends and receives critical signals
between the flight control computer (FCC) and the flight control
surfaces. We are issuing this AD to address the unsafe condition on
these products.

DATES: This AD is effective October 15, 2018.
The Director of the Federal Register approved the incorporation by
reference of certain publications listed in this AD as of October 15,
2018.
We must receive comments on this AD by November 13, 2018.

ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the
instructions for submitting comments.
Fax: 202-493-2251.
Mail: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE, Washington, DC 20590.
Hand Delivery: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE, Washington, DC 20590, between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays.
For service information identified in this final rule, contact
Gulfstream Aerospace Corporation, Technical Publications Dept., P.O.
Box 2206, Savannah, GA 31402-2206; telephone: 800-810-4853; fax: 912-
965-3520; email: pubs@gulfstream.com; internet: http://www.gulfstream.com
/product-support/technical-publications. You may view
this service information at the FAA, Policy and Innovation Division,
901 Locust, Kansas City, Missouri 64106. For information on the
availability of this material at the FAA, call (816) 329-4148. It is
also available on the internet at http://www.regulations.gov by
searching for and locating Docket No. FAA-2018-0870.

Examining the AD Docket

You may examine the AD docket on the internet at http://www.regulations.
gov by searching for and locating Docket No. FAA-2018-
0870; or in person at Docket Operations between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays. The AD docket contains
this final rule, the regulatory evaluation, any comments received, and
other information. The street address for Docket Operations (phone:
800-647-5527) is listed above. Comments will be available in the AD
docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Myles Jalalian, Aerospace Engineer,
Systems and Equipment Section, AIR-7A3, Atlanta ACO Branch, FAA, 1701
Columbia Avenue, College Park, GA 30337; phone: 404-474-5572; fax: 404-
474-5606; email: Myles.Jalalian@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

On Gulfstream Model GVI airplanes, the FCC and the remote
electronics unit (REU) communicate with each other by means of bi-
directional data buses, referred to as BD429. Gulfstream notified us
that loss of bi-directional (Transmit/Receive) BD429 communication, due
to wire/connector failures, between the REU and the FCC would result in
the display of a cyan ``FCS MAINTENANCE REQUIRED'' advisory message on
the crew alerting system (CAS). Because this cyan advisory message does
not directly indicate that BD429 communication has failed, the aircraft
can be dispatched with this advisory message. The Model GVI system
depends on the BD429 bus to assure signal transmission to address a
linear variable differential transformer (LVDT) disconnect monitor and/
or surface oscillatory monitor event.
During recent developmental testing, Gulfstream discovered that
certain BD429 failures prevent the shutdown of a flight control surface
that would normally occur during an oscillatory or LVDT disconnect
event. The only indication of the failure is a cyan ``FCS MAINTENANCE
REQUIRED'' advisory message on the CAS.
If the FCC cannot receive information from the REU that a
particular flight control surface had an event, then the FCC cannot
issue a command to place that particular flight control surface into
standby/damped bypass mode. The REU will still receive flight control
commands from the FCC via the secondary (receive only) bus; however,
because the secondary bus is receive-only for certain REUs, the FCC
will no longer receive REU data needed for the LVDT disconnect monitor
and/or surface oscillatory monitor for the impacted flight control
surface.
This condition (results in a cyan CAS message, but does not
indicate the exact reason) can remain latent for up to one year. To
date, there have been no known events or failures of the BD429
communications bus wiring or connectors in the field. However, the
Gulfstream GVI fleet has experienced multiple in-flight flight control
events requiring a standby command sent over the BD429 bus to keep the
airplane safe. Since the GVI system uses these monitors to mitigate
potentially unsafe failure modes, dispatch with their loss leaves the
aircraft one failure away from a potential loss of control event.
This condition, if not addressed, could result in the FCC's
inability to identify when a problematic flight control surface needs
to be damped, which could result in loss of control of the airplane.

Related Service Information Under 1 CFR Part 51

We reviewed Gulfstream Aerospace G650 AFM Supplement No. G650-2018-
01, dated August 14, 2018; and Gulfstream Aerospace G650ER AFM
Supplement No. G650ER-2018-01, dated August 14, 2018. For each
applicable airplane configuration, the AFM supplement provides
instructions and warnings to the Normal Procedures and Abnormal
Procedures section of the AFM for the pilot to follow if a cyan ``FCS
MAINTENANCE REQUIRED'' CAS message displays with the airplane on the
ground or in flight. This service information is reasonably available
because the interested parties have access to it through their normal
course of business or by the means identified in the ADDRESSES section.

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 the same type design.

AD Requirements

This AD requires revising the Normal and Abnormal Procedures
sections of the AFM by adding instructions and warnings for the pilot
if a cyan ``FCS MAINTENANCE REQUIRED'' CAS message displays with the
airplane on the ground or in flight.

Interim Action

We consider this AD interim action. Gulfstream is analyzing the
failures and working to develop a terminating action that will address
the unsafe condition identified in this AD. Once this action is
developed, approved, and available, we might consider additional
rulemaking.

FAA's Justification and Determination of the Effective Date

An unsafe condition exists that requires the immediate adoption of
this AD without providing an opportunity for public comments prior to
adoption. The FAA has found that the risk to the flying public
justifies waiving notice and comment prior to adoption of this rule
because the inability of the FCC to send a standby command when the
BD429 bus is in a failed state could leave the airplane with only one
level of protection from a catastrophic flight control failure.
Therefore, we find good cause that notice and opportunity for prior
public comment are impracticable. In addition, for the reason stated
above, we find that good cause exists for making this amendment
effective in less than 30 days.

Comments Invited

This AD is a final rule that involves requirements affecting flight
safety and was not preceded by notice and an opportunity for public
comment. However, we invite you to send any written data, views, or
arguments about this final rule. Send your comments to an address
listed under the ADDRESSES section. Include the docket number FAA-2018-
0870 and Product Identifier 2018-CE-047-AD at the beginning of your
comments. We specifically invite comments on the overall regulatory,
economic, environmental, and energy aspects of this final rule. We will
consider all comments received by the closing date and may amend this
final rule because of those comments.
We will post all comments we receive, without change, to http://www.
regulations.gov, including any personal information you provide. We
will also post a report summarizing each substantive verbal contact we
receive about this final rule.

Costs of Compliance

We estimate that this AD affects 213 airplanes of U.S. registry.
We estimate the following costs to comply with this AD:

Estimated Costs

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.
This AD is issued in accordance with authority delegated by the
Executive Director, Aircraft Certification Service, as authorized by
FAA Order 8000.51C. In accordance with that order, issuance of ADs is
normally a function of the Compliance and Airworthiness Division, but
during this transition period, the Executive Director has delegated the
authority to issue ADs applicable to small airplanes, gliders,
balloons, airships, domestic business jet transport airplanes, and
associated appliances to the Director of the Policy and Innovation
Division.

Regulatory Findings

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 above, 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, 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.

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):