DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-0992; Product Identifier 2019-NM-197-AD; Amendment
39-21016; AD 2019-25-17]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all
The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER
(Model 737 NG) series airplanes (although the scope of the AD
requirements is limited to operation at specific runways in the U.S.,
Colombia, and Guyana). This AD requires revising the airplane flight
manual (AFM) to prohibit selection of certain runways for airplanes
equipped with certain software. This AD was prompted by reports of
display electronic unit (DEU) software errors on airplanes with a
selected instrument approach to a specific runway. The FAA is issuing
this AD to address the unsafe condition on these products.

DATES: This AD is effective December 27, 2019.

The FAA must receive comments on this 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.

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-
0992; 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 is listed
above. Comments will be available in the AD docket shortly after
receipt.

FOR FURTHER INFORMATION CONTACT: David Sumner, Aerospace Engineer,
Systems and Equipment Section, FAA, Seattle ACO Branch, 2200 South
216th St., Des Moines, WA 98198; phone and fax: 206-231-3538; email:
David.Sumner@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

The FAA received reports earlier this year of three incidents of
display electronic unit (DEU) software errors on Model 737 NG airplanes
flying into runway PABR in Barrow, Alaska. All six display units (DUs)
blanked with a selected instrument approach to a runway with a 270-
degree true heading, and all six DUs stayed blank until a different
runway was selected. The Integrated Standby Flight Display (ISFD) and
Heads-Up-Display (HUD) remained operational during this failure of the
primary flight displays. The investigation has traced the behavior to a
combination of common display system (CDS) block point (BP) 15 software
in the DEUs and U12 or later software in the flight management computer
(FMC). The investigation revealed that the problem occurs when this
combination of software is installed and a susceptible runway with a
270-degree true heading is selected for instrument approach. Not all
runways with a 270-degree true heading are susceptible; only seven
runways worldwide, as identified in this AD, have latitude and
longitude values that cause the blanking behavior. If CDS BP15 software
and FMC U12 or later software are installed, all six DUs can blank when
a susceptible runway with a 270-degree true heading is selected. The
FAA has confirmed that the faulty version of DEU software has already
been removed from all airplanes conducting scheduled airline service
into the affected airports. This AD is intended to address unscheduled
diversions and Boeing Business Jet (BBJ) flights into the affected
airports. This condition, if not addressed, could prevent continued
safe flight and landing.

FAA's Determination

The FAA is issuing this AD because the agency 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 AFM to prohibit selection of certain
runways for airplanes equipped with certain software.
Although all Model 737 NG airplanes are affected, the scope of the
AD requirements is limited to operation at specific runways in the
U.S., Colombia, and Guyana, as identified in this AD.

Interim Action

The FAA considers this AD interim action. The manufacturer is
currently developing a software update that will address the unsafe
condition identified in this AD. Once this modification is developed,
approved, and available, the FAA 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 combination of CDS BP15 software and FMC U12 or later
software installed can result in all six DUs blanking when a
susceptible runway with 270 degree true heading is selected; this
condition can prevent continued safe flight and landing. The compliance
time for the required action is shorter than the time necessary for the
public to comment and for publication of the final rule. Therefore, the
FAA finds good cause that notice and opportunity for prior public
comment are impracticable. In addition, for the reasons stated above,
the FAA finds 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, the FAA invites 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-2019-
0992 and Product Identifier 2019-NM-197-AD at the beginning of your
comments. The FAA specifically invites comments on the overall
regulatory, economic, environmental, and energy aspects of this final
rule. The FAA will consider all comments received by the closing date
and may amend this final rule 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 final rule.

Regulatory Flexibility Act

The requirements of the Regulatory Flexibility Act (RFA) do not
apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt
a rule without prior notice and comment. Because the FAA has determined
that it has good cause to adopt this rule without notice and comment,
RFA analysis is not required.

Costs of Compliance

The FAA estimates that this AD affects 1,739 airplanes of U.S.
registry. The FAA estimates 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.

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 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, and

(2) Will not affect intrastate aviation in Alaska.

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):