DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2018-1006; Product Identifier 2018-NM-142-AD; Amendment
39-19565; AD 2019-03-13]
RIN 2120-AA64

Airworthiness Directives; Gulfstream Aerospace LP (Type
Certificate Previously Held by Israel Aircraft Industries, Ltd.)
Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for certain
Gulfstream Aerospace LP Model Gulfstream G150 airplanes. This AD was
prompted by reports of corrosion in the solder joints of the upper and
lower front relay box connectors to the printed circuit board. This AD
requires replacement of the existing relay boxes with modified boxes.
We are issuing this AD to address the unsafe condition on these
products.

DATES: This AD is effective April 8, 2019.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of April 8,
2019.

ADDRESSES: For service information identified in this final rule,
contact Gulfstream Aerospace Corporation, P.O. Box 2206, Mail Station
D-25, Savannah, GA 31402-2206; telephone 800-810-4853; fax 912-965-
3520; email pubs@gulfstream.com; internet http://www.gulfstream.com/product_support/technical_pubs/pubs/index.htm.
You may view this service information at the FAA, Transport Standards Branch,
2200 South 216th St., Des Moines, WA. For information on the availability of this
material at the FAA, call 206-231-3195. It is also available on the
internet at http://www.regulations.gov by searching for and locating
Docket No. FAA-2018-1006.

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-
1006; 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 address for Docket Operations (phone: 800-647-
5527) is U.S. Department of Transportation, Docket Operations, M-30,
West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE,
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Tom Rodriguez, Aerospace Engineer,
International Section, Transport Standards Branch, FAA, 2200 South
216th St., Des Moines, WA 98198; telephone and fax 206-231-3226.

SUPPLEMENTARY INFORMATION:

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR
part 39 by adding an AD that would apply to certain Gulfstream
Aerospace LP Model Gulfstream G150 airplanes. The NPRM published in the
Federal Register on December 11, 2018 (83 FR 63596). The NPRM was
prompted by reports of corrosion in the solder joints of the upper and
lower front relay box connectors to the printed circuit board. The NPRM
proposed to require replacement of the existing relay boxes with
modified boxes.
We are issuing this AD to address corrosion in the front relay box
connector solder joints. If not addressed, this condition could cause
false crew alerting system (CAS) messages, such as slats unbalance,
auto slats fail, and Mach trim fail, which could interfere with
continued safe operation of the airplane.
The Civil Aviation Authority of Israel (CAAI), which is the
aviation authority for Israel, has issued Israeli Airworthiness
Directive ISR-I-24-2018-09-7, dated October 1, 2018 (referred to after
this as the Mandatory Continuing Airworthiness Information, or ``the
MCAI''), to correct an unsafe condition for certain Gulfstream
Aerospace LP Model Gulfstream G150 airplanes. The MCAI states:

The existing Upper and Lower Front Relay Box might be prone to
corrosion in the relay box connector's solder joint to the printed
circuit board. As a result various CAS [crew alerting system]
messages such as slats unbalance and auto slats fail, Mach trim
fail, etc . . . might be reported [and could interfere with
continued safe operation of the airplane]. To prevent this
condition, replacement of existing relay boxes with modified boxes
featuring an added acrylic conformal coating should be performed.
Five occurrences on G150 model in last 3 years had been
reported.

You may examine the MCAI in the AD docket on the internet at http://www.
regulations.gov by searching for and locating Docket No. FAA-2018-1006.

Comments

We gave the public the opportunity to participate in developing
this final rule. We received no comments on the NPRM or on the
determination of the cost to the public.

Conclusion

We reviewed the relevant data and determined that air safety and
the public interest require adopting this final rule as proposed,
except for minor editorial changes. We have determined that these minor
changes:
Are consistent with the intent that was proposed in the
NPRM for addressing the unsafe condition; and
Do not add any additional burden upon the public than was
already proposed in the NPRM.

Related Service Information Under 1 CFR Part 51

Gulfstream has issued Service Bulletin 150-24-193, dated March 30,
2018. This service information describes procedures for removing and
replacing the upper and lower front relay boxes. 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.

Costs of Compliance

We estimate that this AD affects 81 airplanes of U.S. registry. We
estimate the following costs to comply with this AD:

Estimated Costs for Required Actions

According to the manufacturer, some or all of the costs of this AD
may be covered under warranty, thereby reducing the cost impact on
affected individuals. We do not control warranty coverage for affected
individuals. As a result, we have included all known costs in our cost
estimate.

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 transport category airplanes and
associated appliances to the Director of the System Oversight 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 the 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):