[Federal Register Volume 86, Number 108 (Tuesday, June 8, 2021)]
[Proposed Rules]
[Pages 30398-30399]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-11813]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[FAA Docket No. FAA-2020-0994; Project Identifier AD-2020-00687-T]
RIN 2120-AA64


Airworthiness Directives; Gulfstream Aerospace Corporation 
Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Proposed rule; withdrawal.

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SUMMARY: The FAA is withdrawing a notice of proposed rulemaking (NPRM) 
that proposed to adopt a new airworthiness directive (AD) for certain 
Gulfstream Aerospace Corporation (Gulfstream) Model GVII-G600 
airplanes. The NPRM was prompted by a report that a failure mode in the 
data concentration network (DCN) software causes the pitch attitude 
value to freeze on the primary flight display (PFD) for up to 20 
seconds. The NPRM proposed to require updating the DCN and flight deck 
master operating system (MOS) software. Since issuance of the NPRM, the 
FAA has determined that there is not an unsafe condition because all 
affected airplanes have updated software. Accordingly, the NPRM is 
withdrawn.

DATES:  As of June 8, 2021, the proposed rule, which published in the 
Federal Register on February 23, 2021 (86 FR 10875), is withdrawn.

ADDRESSES: 

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2020-0994; 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 AD action, the 
regulatory evaluation, any comments received, and other information. 
The street address for Docket Operations 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: Myles Jalalian, Aviation Safety 
Engineer, 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:

Background

    The FAA issued an NPRM that proposed to amend 14 CFR part 39 by 
adding an AD that would apply to certain serial-numbered Gulfstream 
Model GVII-G600 airplanes. The NPRM published in the Federal Register 
on February 23, 2021 (86 FR 10875). The NPRM was prompted by a report 
of a failure mode in the DCN software that causes pitch attitude value 
to freeze on the PFD for up to 20 seconds, which results in temporarily 
incorrect pitch indications.
    The effect is evident only if the pitch of the airplane changes 
during the 20 second reset window. After 20 seconds, the system returns 
to normal. The standby flight display and heads up display are 
unaffected by this failure mode and continue to display the correct 
pitch attitude. However, there is not an alert or annunciation that 
informs the flight crew of a stale (frozen) pitch display or 
potentially misleading flight information.
    The NPRM proposed to require installing the MOS software update 
part number EB60001034-0106, updating the DCN software level to version 
10.10.12 in support of the MOS software update, and operationally 
checking the installations. Incorrect pitch indications could result in 
the loss of control of the airplane during certain phases of flight 
during instrument meteorological conditions.

Actions Since the NPRM Was Issued

    After issuance of the NPRM, the FAA received a comment from 
Gulfstream recommending the FAA withdraw the NPRM based on full fleet 
compliance. All Gulfstream Model GVII-G600 airplanes have corrected the 
unsafe condition by complying with the proposed software update. The 
FAA has determined that the unsafe condition has been removed from the 
fleet. In addition, since Gulfstream controls the software, it is 
unlikely the unsafe condition will be re-introduced.

[[Page 30399]]

    Based on the above information, the FAA has determined that AD 
action is not warranted and the proposal should be withdrawn.
    Withdrawal of the NPRM constitutes only such action and does not 
preclude the FAA from further rulemaking on this issue, nor does it 
commit the FAA to any course of action in the future.

Regulatory Findings

    Since this action only withdraws an NPRM, it is neither a proposed 
AD nor a final rule. This action, therefore, is not covered under 
Executive Order 12866 or the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

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

The Withdrawal

    Accordingly, the notice of proposed rulemaking, which published in 
the Federal Register on February 23, 2021 (86 FR 10875), is withdrawn.

    Issued on May 28, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-11813 Filed 6-7-21; 8:45 am]
BILLING CODE 4910-13-P


