DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-1060; Product Identifier 2018-CE-020-AD]
RIN 2120-AA64

Airworthiness Directives; Gulfstream Aerospace Corporation
Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for all Gulfstream Aerospace Corporation (Gulfstream) Model G-IV
airplanes. This proposed AD was prompted by reports of un-commanded
nose wheel steering turns. This proposed AD would require replacing the
nose wheel steering servo valve manifold, incorporating revised
operating procedures into the airplane flight manual (AFM), doing a
records inspection for any incidents of un-commanded nose wheel
steering turns, and reporting the results to the FAA. The FAA is
proposing this AD to address the unsafe condition on these products.

DATES: The FAA must receive comments on this proposed AD by February 10, 2020.

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 https://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: Deliver to Mail address above between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this NPRM, contact Gulfstream
Aerospace Corporation, Technical Publications Dept., P.O. Box 2206,
Savannah, Georgia 31402-2206; telephone: (800) 810-4853; fax 912-965-
3520; email: pubs@gulfstream.com; internet: https://www.gulfstream.com/
customer-support. 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.

Examining the AD Docket

You may examine the AD docket on the internet at https://www.regulations.gov
by searching for and locating Docket No. FAA-2019-1060; 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 NPRM, the regulatory evaluation, any comments received, and other
information. The street address for Docket Operations is listed above.
Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Alex Armas, Aerospace Engineer,
Atlanta ACO Branch, FAA, 1701 Columbia Avenue, College Park, Georgia
30337; phone: (404) 474-5538; fax: (404) 474-5605; email:
alex.armas@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under the ADDRESSES section. Include "Docket No. FAA-2019-1060;
Product Identifier 2018-CE-020-AD" at the beginning of your comments.
The FAA specifically invite comments on the overall regulatory,
economic, environmental, and energy aspects of this NPRM. The FAA will
consider all comments received by the closing date and may amend this
NPRM because of those comments.

The FAA will post all comments received, without change, to
https://www.regulations.gov, including any personal information you provide.
The FAA will also post a report summarizing each substantive verbal
contact received about this NPRM.

Discussion

The FAA received reports of numerous incidents of un-commanded nose
wheel steering turns on Gulfstream Model G-IV airplanes. An
investigation revealed the supplier compromised the seals during
assembly of the electro-hydraulic servo valves, which allows moisture
to enter the valve. During cold soak conditions, the moisture forms ice
crystals in the servo valve armature air gaps, which may cause the
valve armature to displace to a non-neutral position. This condition,
if not addressed, could result in an un-commanded nose wheel position
once power is applied to the nose wheel servo and subsequent lateral
runway departure.

To address this condition, the supplier improved their production
quality control process to reduce the risk of compromised seals in the
nose wheel steering servo valve. Gulfstream also revised the normal,
abnormal, and emergency procedures in the AFMs related to nose wheel
steering un-commanded turns.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Gulfstream IV Customer Bulletin Number 244, dated
March 12, 2018; Gulfstream G300 Customer Bulletin 244, dated March 12,
2018; and Gulfstream G400 Customer Bulletin 244, dated March 12, 2018.
For the applicable airplane configuration, each customer bulletin
describes procedures for replacing the nose wheel steering servo valve
manifold assembly.

The FAA also reviewed Gulfstream IV Airplane Flight Manual,
Gulfstream Aerospace Document Number GAC-AC-GIV-OPS-0001, Revision 52,
dated October 30, 2017; Gulfstream G300 Airplane Flight Manual,
Gulfstream Aerospace Document Number GAC-AC-G300-OPS-0001, Revision 20,
dated October 30, 2017; and Gulfstream G400 Airplane Flight Manual,
Gulfstream Aerospace Document Number GAC-AC-G400-OPS-0001, Revision 20,
dated October 30, 2017. For the applicable airplane configuration, each
AFM document provides revisions to the AFM with instructions for flight
crew to follow if un-commanded nose wheel steering turns occur.

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

The FAA is proposing this AD because it 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.

Proposed AD Requirements

This proposed AD would require revising the AFM and replacing the
nose wheel steering servo valve manifold. This proposed AD would also
require a records inspection for any incidents of un-commanded nose
wheel steering turns and reporting the results to the FAA.

Differences Between This Proposed AD and the Service Information

The Gulfstream customer bulletins require reporting compliance with
the bulletins to Gulfstream. This proposed AD does not contain that
requirement; however, this proposed AD would require reporting any
known occurrences of un-commanded nose wheel steering turns to the FAA.
The Gulfstream customer bulletins include a compliance time of 48
months beginning on March 12, 2018. The compliance time for this
proposed AD is 36 months after the effective date of the AD.

Costs of Compliance

The FAA estimates that this proposed AD would affect 425 airplanes
of U.S. registry.

The FAA estimates the following costs to comply with this proposed AD:

Estimated Costs

According to the manufacturer, some of the costs of this proposed
AD may be covered under warranty, thereby reducing the cost impact on
affected individuals. The FAA does not control warranty coverage for
affected individuals. As a result, the FAA has included all costs in
this cost estimate.

Paperwork Reduction Act

A federal agency may not conduct or sponsor, and a person is not
required to respond to, nor shall a person be subject to a penalty for
failure to comply with a collection of information subject to the
requirements of the Paperwork Reduction Act unless that collection of
information displays a currently valid OMB Control Number. The OMB
Control Number for this information collection is 2120-0056. Public
reporting for this collection of information is estimated to be
approximately 2 hours per response, including the time for reviewing
instructions, searching existing data sources, gathering and
maintaining the data needed, completing and reviewing the collection of
information. All responses to this collection of information are
mandatory as required by this AD; the nature and extent of
confidentiality to be provided, if any. Send comments regarding this
burden estimate or any other aspect of this collection of information,
including suggestions for reducing this burden to: Information
Collection Clearance Officer, Federal Aviation Administration, 10101
Hillwood Parkway, Fort Worth, TX 76177-1524.

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.

The FAA is 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 proposed 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

The FAA determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would 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 this proposed regulation:

(1) Is not a "significant regulatory action" under Executive Order 12866,

(2) Will not affect intrastate aviation in Alaska, 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.

List of Subjects in 14 CFR Part 39

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

The Proposed Amendment

Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 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):