preamble attached >>>
ADs updated daily at www.Tdata.com
2014-20-06 THE BOEING COMPANY: Amendment 39-17979; Docket No. FAA-2013-0792; Directorate Identifier 2013-NM-118-AD.
(a) EFFECTIVE DATE

    This AD is effective November 5, 2014.

(b) AFFECTED ADS

    None.

(c) APPLICABILITY

    This AD applies to The  Boeing Company airplanes, certificated in  any
    category, as identified in paragraphs (c)(1) and (c)(2) of this AD.

(1) Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes.

(2) Model  777-200, 777-200LR, 777-300, 777-300ER,  and 777F  series  air-
    planes.

(d) SUBJECT

    Air Transport Association (ATA) of America Code 31, Instruments.

(e) UNSAFE CONDITION

    This AD was prompted by  testing reports on certain Honeywell  phase 3
    display  units  (DUs).  These DUs  exhibited  susceptibility  to radio
    frequency emissions in WiFi  frequency bands at radiated  power levels
    below  the  levels that  the  displays are  required  to tolerate  for
    certification of WiFi  system installations. The  phase 3 DUs  provide
    primary flight  information, including  airspeed, altitude,  pitch and
    roll attitude, heading, and navigation information, to the flightcrew.
    We are issuing this AD to prevent loss of flight-critical  information
    displayed to the flightcrew during a critical phase of flight, such as
    an approach or takeoff, which could result in loss of airplane control
    at an altitude  insufficient for recovery,  or controlled flight  into
    terrain.

(f) COMPLIANCE

    Comply  with this  AD within  the compliance  times specified,  unless
    already done.

(g) INSPECTION, SOFTWARE INSTALLATION, AND DU INSTALLATION

    Within  60 months  after the  effective date  of this  AD: Inspect  to
    determine if any  phase 3 DUs  are installed. If  any phase 3  DUs are
    installed, within 60  months after the  effective date of  this AD, do
    the applicable actions required by paragraph (g)(1) or (g)(2) of  this
    AD. A review of airplane maintenance records is acceptable in lieu  of
    this inspection  if the  phase number  of the  DUs can be conclusively
    determined from that review.

(1) For  Model 737 airplanes:  Remove  all  phase 3 common display  system
    (CDS) DUs and replace with phase 1,  phase 2, or phase 3A CDS DUs.  If
    any phase 3 CDS  DUs are replaced with  phase 3A CDS DUs,  replace the
    phase 3  CDS DUs  and install  new database  software into the display
    electronics units, in accordance with the Accomplishment  Instructions
    of  Boeing  Special  Attention  Service  Bulletin  737-31-1471,  dated
    November 29, 2012.

(2) For Model 777 airplanes: Remove all phase 3 DUs and replace with phase
    1, phase  2, or  phase 3A  DUs. If  any phase  3 DUs are replaced with
    phase 3A  DUs, replace  the phase  3 DUs  and install  the DU database
    software  into  the  left and  right  airplane  information management
    system core  processor module/graphics  generator, in  accordance with
    the Accomplishment  Instructions of  Boeing Special  Attention Service
    Bulletin 777-31-0187, dated November 29, 2012.

(h) ALTERNATIVE METHODS OF COMPLIANCE (AMOCS)

(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, has the
    authority to approve AMOCs for this AD,  if requested using the proce-
    dures found  in 14 CFR 39.19.  In accordance  with 14 CFR 39.19,  send
    your request to your  principal  inspector  or  local Flight Standards
    District Office,  as  appropriate.  If sending information directly to
    the manager of the ACO, send it to the attention of the person identi-
    fied in the Related Information section of this AD. Information may be
    emailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.

(2) Before using any approved AMOC,  notify your appropriate principal in-
    spector,  or lacking a principal inspector,  the  manager of the local
    flight standards district office/certificate holding district office.

(3) An AMOC  that  provides  an acceptable level of safety may be used for
    any  repair  required by  this  AD if  it  is approved  by  the Boeing
    Commercial  Airplanes ODA  that has  been authorized  by the  Manager,
    Seattle  ACO,  to make  those  findings. For  a  repair method  to  be
    approved,  the  repair  must  meet  the  certification  basis  of  the
    airplane, and the approval must specifically refer to this AD.

(i) RELATED INFORMATION

    For  more  information  about  this  AD,  contact  Jeffrey  W. Palmer,
    Aerospace Engineer,  Systems and  Equipment Branch,  ANM-130S, Seattle
    Aircraft Certification Office,  FAA,  1601 Lind Avenue SW., Renton, WA
    98057-3356; phone: 425-917-6472;  fax: 425-917-6590; email: jeffrey.w.
    palmer@faa.gov.

(j) MATERIAL INCORPORATED BY REFERENCE

(1) The  Director  of  the  Federal Register approved the incorporation by
    reference (IBR) of the  service  information  listed in this paragraph
    under 5 U.S.C. 552(a) and 1 CFR part 51.

(2) You must use this  service information as applicable to do the actions
    required by this AD, unless the AD specifies otherwise.

(i) Boeing Special Attention Service Bulletin 737-31-1471,  dated November
    29, 2012.

(ii) Boeing Special Attention Service Bulletin 777-31-0187, dated November
     29, 2012.

(3) For Boeing service information identified in this AD,  contact  Boeing
    Commercial Airplanes,  Attention: Data & Services Management, P.O. Box
    3707,  MC 2H-65,  Seattle,  WA  98124-2207;   telephone  206-544-5000,
    extension 1; fax 206-766-5680; Internet https://www.myboeingfleet.com.

(4) You  may  view  this  service  information  at  FAA Transport Airplane
    Directorate, 1601 Lind Avenue SW., Renton, Washington. For information
    on the availability of this material at the FAA, call 425-227-1221.

(5) You  may  view  this  service  information  that  is  incorporated  by
    reference at the National Archives and Records Administration  (NARA).
    For information  on the  availability of  this material  at NARA, call
    202-741-6030,  or go to: http://www.archives.gov/federal-register/cfr/
    ibr-locations.html.

Issued  in  Renton, Washington,  on September 19, 2014.  Jeffrey E. Duven,
Manager, Transport Airplane Directorate, Aircraft Certification Service.

FOR FURTHER INFORMATION CONTACT:  Jeffrey W. Palmer,  Aerospace  Engineer,
Systems  and  Equipment Branch,  ANM-130S,  Seattle Aircraft Certification
Office, FAA, 1601 Lind Avenue SW., Renton, WA 98057-3356;  phone: 425-917-
6472; fax: 425-917-6590; email: jeffrey.w.palmer@faa.gov.
PREAMBLE 

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2013-0792; Directorate Identifier 2013-NM-118-AD;
Amendment 39-17979; AD 2014-20-06]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: We are adopting a new airworthiness directive (AD) for all The
Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER
series airplanes, and Model 777 airplanes. This AD was prompted by
testing reports on certain Honeywell phase 3 display units (DUs). These
DUs exhibited susceptibility to radio frequency emissions in WiFi
frequency bands at radiated power levels below the levels that the
displays are required to tolerate for certification of WiFi system
installations. The phase 3 DUs provide primary flight information
including airspeed, altitude, pitch and roll attitude, heading, and
navigation information to the flightcrew. This AD requires replacing
the existing phase 3 DUs with phase 1, phase 2, or phase 3A DUs, and
for certain replacement DUs, installing new DU database software. We
are issuing this AD to prevent loss of flight-critical information
displayed to the flightcrew during a critical phase of flight, such as
an approach or takeoff, which could result in loss of airplane control
at an altitude insufficient for recovery, or controlled flight into
terrain.

DATES: This AD is effective November 5, 2014.
The Director of the Federal Register approved the incorporation by
reference of certain publications listed in this AD as of November 5,
2014.

ADDRESSES: For service information identified in this AD, contact
Boeing Commercial Airplanes, Attention: Data & Services Management,
P.O. Box 3707, MC 2H-65, Seattle, WA 98124-2207; telephone 206-544-
5000, extension 1; fax 206-766-5680; Internet https://www.myboeingfleet.
com. You may view this referenced service information
at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW.,
Renton, WA. For information on the availability of this material at the
FAA, call 425-227-1221.

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-2013-
0792; or in person at the Docket Management Facility between 9 a.m. and
5 p.m., Monday through Friday, except Federal holidays. The AD docket
contains this AD, the regulatory evaluation, any comments received, and
other information. The address for the Docket Office (phone: 800-647-
5527) is Docket Management Facility, 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: Jeffrey W. Palmer, Aerospace Engineer,
Systems and Equipment Branch, ANM-130S, Seattle Aircraft Certification
Office, FAA, 1601 Lind Avenue SW., Renton, WA 98057-3356; phone: 425-
917-6472; fax: 425-917-6590; email: jeffrey.w.palmer@faa.gov.

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 all The Boeing Company
Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes,
and Model 777 airplanes. The NPRM published in the Federal Register on
September 24, 2013 (78 FR 58487). The NPRM was prompted by testing
reports on certain Honeywell phase 3 DUs. These DUs exhibited
susceptibility to radio frequency emissions in WiFi frequency bands at
radiated power levels below the levels that the displays are required
to tolerate for certification of WiFi system installations. The phase 3
DUs provide primary flight information including airspeed, altitude,
pitch and roll attitude, heading, and navigation information to the
flightcrew. The NPRM proposed to require replacing the existing phase 3
DUs with new phase 3A DUs and installing new DU database software. We
are issuing this AD to prevent loss of flight-critical information
displayed to the flightcrew during a critical phase of flight, such as
an approach or takeoff, which could result in loss of airplane control
at an altitude insufficient for recovery, or controlled flight into
terrain.

Clarification of Cause of Unsafe Condition

The cause of the unsafe condition stated in the Discussion section
of this AD is a known susceptibility of the Phase 3 DUs to RF
transmissions inside and outside of the airplane. This susceptibility
has been verified to exist in a range of RF spectrum (mobile satellite
communications, cell phones, air surveillance and weather radar, and
other systems), and is not limited to WiFi transmissions.

Comments

We gave the public the opportunity to participate in developing
this AD. The following presents the comments received on the proposal
(78 FR 58487, September 24, 2013), and the FAA's response to each
comment.

Request To Change Applicability

Three commenters requested that we revise the applicability. A4A
requested that we change the applicability to address only airplanes
that have phase 3 DUs installed. Mr. Philipp Schmid requested that the
applicability only address airplanes that have a WiFi system installed
in the cabin. All Nippon Airways (ANA) requested that we revise
applicability paragraph (c) of the proposed AD (78 FR 58487, September
24, 2013) to refer to the airplanes identified in Boeing Special
Attention Service Bulletin 737-31-1471, dated November 29, 2012; and
Boeing Special Attention Service Bulletin 777-31-0187, dated November
29, 2012.
A4A stated that the FAA is making the NPRM (78 FR 58487, September
24, 2013) applicable to all Model 737 NG and Model 777 series
airplanes, regardless of the operator's intent to install a Wi-Fi
system. A4A expressed that in paragraph (e) of the proposed AD, the FAA
acknowledges that the unsafe condition is directly related to
electromagnetic interference (EMI) characteristics exhibited at
specific frequency ranges related to Wi-Fi transmission. A4A stated
that the phase 3 DUs have passed all applicable certification testing
required for approval and use on transport category airplanes,
including the DO-160 environmental standards. A4A asserted
that the phase 3 display units have proven to be reliable under normal
operating conditions. A4A also stated that the failure mode identified
by the NPRM is specific to an additional test procedure prescribed by
DO-294C that is required only as part of the certification requirements
of an operator-installed Wi-Fi system.
ANA stated that the those airplanes not specified in Boeing Special
Attention Service Bulletin 737-31-1471, dated November 29, 2012; and
Boeing Special Attention Service Bulletin 777-31-0187, dated November
29, 2012; were/will be delivered with the requested changes in
production.
We partially agree with the commenters' requests. We recognize that
operators will not be able to comply with the proposed replacement
specified in paragraph (g) of the proposed AD (78 FR 58487, September
24, 2013) if airplanes do not have any phase 3 DUs installed.
Therefore, we have revised paragraph (g) of this AD to allow operators
to inspect to determine if phase 3 DUs are installed and if no phase 3
DUs are installed, no further action is necessary.
The intent of this AD is to remove all DUs with an unsafe condition
from all Model 737NG and Model 777 series airplanes, regardless of
whether or not the airplanes are listed in the effectivity of Boeing
Special Attention Service Bulletin 737-31-1471, dated November 29,
2012; and Boeing Special Attention Service Bulletin 777-31-0187, dated
November 29, 2012.
DUs can be rotated among other airplanes. As noted by Boeing, the
phase 3 DU's are interchangeable and intermixable with earlier versions
of DU's on 737NG and 777 airplanes, and may have been installed on any
737NG or 777 airplanes, and may be in operator spares inventory.
In regards to A4A's comment that phase 3 DUs have proven to be
reliable under normal operating conditions, the testing that revealed
the DU susceptibility was verified by inspection of the phase 3 DU
qualification test reports provided by the DU manufacturer. The intent
of this AD is to eliminate this known susceptibility of the phase 3 DUs
to RF transmissions, including those from sources outside the airplane.
This susceptibility is not limited to WiFi transmissions, but has been
verified to exist in a range of the RF spectrum used by mobile
satellite communications, cell phones, air surveillance and weather
radar, and other systems. The phase 3 displays that failed the test did
so substantially below the RF immunity levels set forth in paragraph 1
of the ``High Intensity Radiated Fields (HIRF)'' section of the
preamble to 737 Special Condition 25-ANM-132, dated September 26, 1997;
and paragraph 1 of the HIRF discussion in the preamble to 777 Special
Condition 25-ANM-78, dated November 10, 1993. Under the provisions of
paragraph (h) of this AD, we will consider requests for approval of an
AMOC if sufficient data are submitted to substantiate that the DU
change is not necessary. We have not changed this AD in this regard.

Request To Withdraw the NPRM (78 FR 58487, September 24, 2013)

Virgin Australia (VOZ), Air France (AFA), Ryanair, Airlines for
America (A4A), and Honeywell requested that we withdraw or review the
need for the NPRM (78 FR 58487, September 24, 2013).
VOZ stated that during testing of the WiFi inflight entertainment
system on the VOZ Model 737NG fleet, it noted that the DU blanking
occurred only when the WiFi radiated power source (set-up in the flight
deck) was increased to a high level. VOZ also stated that under normal
operating conditions of the WiFi radiated power, there was no blanking
of the DU, but interference was present only at a certain frequency.
VOZ commented that as part of the WiFi supplemental type certificate
(STC), a decal is installed in the flight deck that states that WiFi is
not to be used when airplane engines are running for the purpose of
flight, and flight operation procedures also restrict transmitting
devices in the flight deck. We infer that VOZ requested that we
withdraw the NPRM (78 FR 58487, September 24, 2013).
AFA stated that since April 2013, AFA and Koninklijke Luchtvaart
Maatschappij N.V.(KLM) have operated two Model 777 airplanes equipped
with WiFi that have had no DU problems. AFA commented that the WiFi
signal is available on the flight deck, but its use is prohibited. AFA
suggested that it is likely that the WiFi signal level is too low to
cause the DU blanking problems that led to the NPRM (78 FR 58487,
September 24, 2013). AFA also stated that on its other Model 777
airplanes (85 airplanes equipped with phase 2 or 3 DUs with no WiFi),
neither AFA nor KLM, have experienced DU problems. AFA stated that the
DU discrepancies are caused by WiFi interference directly associated
with design defects of the phase 3 DU, and since replacement cost is at
customer expense, estimated more than $2,000 per DU, the cost to comply
with the NPRM for the quantity of phase 3 DUs in service in both fleets
is not reasonable or justified.
Ryanair and Honeywell commented that testing performed on the phase
3 DUs concluded that a Federal Communications Commission (FCC)
compliant WiFi radiating device does not result in interference on the
phase 3 DU unless the transmitting device is within 1 meter of the DU.
Ryanair and Honeywell stated that is not possible for FCC compliant
WiFi devices to cause interference to the DUs from outside the airplane
during flight and that intentional emitting devices by passengers are
prohibited from use on an airplane, and in any case will always be more
than the required 1 meter distance from the DU, and consequently cannot
cause interference to the DUs. Ryanair and Honeywell also stated that
the installation and operation of any intentional emitting devices in
the cockpit during flight is subject to regulatory approval and such
regulatory approval process includes electromagnetic interference
testing at WiFi frequencies. Ryanair asserted that requiring the NPRM
(78 FR 58487, September 24, 2013) actions on all airplanes,
irrespective of the installation or operation of WiFi systems in the
cockpit, is imposing a high, and unnecessary, financial burden on
operators.
Honeywell stated that instead of requiring all phase 3 DUs to be
replaced or modified, as proposed by the NPRM (78 FR 58487, September
24, 2013), the need for modifying the DUs should only be considered in
the process for authorizing the use of WiFi devices in the cockpit.
Honeywell explained that since the cockpit is a controlled environment,
the airline has the opportunity to select acceptable devices and
establish procedures for their use and storage that can mitigate any
interference risk. Honeywell stated that Delta Airlines has been safely
operating WiFi-enabled Apple iPads in its flight decks, including those
with phase 3 DUs, based on a waiver granted by the FAA.
Honeywell also stated that they have performed an assessment of
continued operational safety (COS) risk to an external high intensity
radiated field (HIRF) condition using the methods defined in the
Transport Airplane Risk Assessment Methodology (TARAM) Handbook
published by the FAA, Transport Airplane Directorate, and that its
TARAM analysis concluded that the COS risk from external HIRF condition
falls well within the FAA's acceptable risk zone.
A4A requested that we withdraw the NPRM (78 FR 58487, September 24,
2013) because it believes that the risk is not adequately
substantiated, and that
conflicting data exists questioning the susceptibility of the DUs to
WiFi interference. A4A also commented that the economic impact of the
NPRM actions is far greater than the cost estimate stated in the NPRM
and should be acknowledged and weighed against what it characterized as
questionable risk.
We do not agree with the commenters' request to withdraw the NPRM
(78 FR 58487, September 24, 2013). The testing that revealed the DU
susceptibility to WiFi interference was verified by inspection of the
phase 3 DU qualification test reports provided by the DU manufacturer.
The intent of this final rule is to eliminate this known susceptibility
of the phase 3 DUs to radio frequency (RF) transmissions, including
those from sources outside the airplane. The phase 3 displays that
failed testing did so substantially below the RF immunity levels set
forth in paragraph 1 of the HIRF section of the preamble to 737 Special
Condition 25-ANM-132, dated September 26, 1997 (http://www.gpo.gov/
fdsys/pkg/FR-2009-09-03/pdf/E9-21299.pdf); and paragraph 1. of the HIRF
discussion in the preamble to 777 Special Condition 25-ANM-78, dated
November 10, 1993 (http://www.gpo.gov/fdsys/pkg/FR-2004-11-08/pdf/
04-24847.pdf).
As part of our assessment of the safety issue in accordance with
our established safety process, the FAA also performed a TARAM analysis
of the issue with the assistance of the airplane manufacturer. This
analysis did not agree with Honeywell's assessment. The FAA issued an
operating rule exemption to Delta Airlines for use of iPads on the
flight deck because it was in the public interest to do so in order to
enable testing and evaluation of other aviation safety-enhancing
technology the FAA was researching. The FAA's exemption was granted to
Delta based on extensive testing and supporting data, use of specially
trained flight crews, and establishment of appropriate operating
procedures to ensure safe flight operations during the time period of
the exemption. The NPRM (78 FR 58487, September 24, 2013) will not be
withdrawn because it meets the intent of correcting the unsafe
condition listed in the SUMMARY section. Under the provisions of
paragraph (h) of this AD, we will consider requests for approval of an
alternative method of compliance (AMOC) if sufficient data are
submitted to substantiate that the DU change is not necessary. We have
not changed this AD in this regard.

Request To Disclose Underlying Data in Support of the NPRM (78 FR
58487, September 24, 2013)


A4A requested that we fully present our underlying data in support
of the NPRM (78 FR 58487, September 24, 2013) risk allegation. Mr.
Philipp Schmid stated that WiFi operational limitations should be
considered in the risk assessment and that to his knowledge, WiFi
systems must be disabled during the critical phases of flight such as
an approach or take-off.
A4A stated that the FAA does not disclose in the NPRM (78 FR 58487,
September 24, 2013), the nature of DU testing conducted nor its source,
and that a rulemaking of this magnitude must be supported in
incontrovertible data from appropriate and reliable sources.
A4A submitted information from Southwest Airlines (SWA) that stated
that SWA collected data from both certified lab and engineering
designed airplane ground tests indicating that the Honeywell phase 3
DUs are not susceptible at or below the energy levels required for
certification. SWA also stated that it has performed extensive testing
with respect to susceptibility of the Honeywell phase 3 DUs in the WiFi
bands outlined in the NPRM (78 FR 58487, September 24, 2013) and that
this testing indicated that significant safety margins are available;
and that there are no threat susceptibilities recorded at or below the
WiFi certification levels. SWA also commented that it has flown
2,375,481 hours with 435 airplanes since WiFi system installation with
no un-attributable DU blanking or blinking defects that would be a
consideration under the NPRM. SWA concluded that ``this experience
indicates a negligible level of risk.''
A4A submitted information from United Airlines (UAL). UAL explained
that an alternate means of assuring an equivalent level of safety while
a replacement program is undertaken has been accepted by FAA at UAL.
UAL stated that it has been granted certification limitations which
allow operation of the WiFi system provided that the flight deck is
placarded to disallow use of transmitting portable electronic devices
(TPED) when engines are operating for purposes of flight. UAL stated it
believes such limitations are the appropriate means to address the
unsafe condition because they apply directly to the certification of
airplane with an operator-installed WiFi system. A4A stated that it
agrees with UAL that such a restriction provides an equivalent level of
safety, for if it did not, it would not have been approved by the FAA.
We do not agree with the commenters' requests. We do not agree to
share the underlying data in the AD. An AD is not an appropriate
vehicle for sharing proprietary data.
The susceptibility of phase 3 DUs to RF transmissions was initially
identified during a WiFi STC installation by an operator and a WiFi
vendor and reported to the FAA. As a result of this discovery, we
performed a risk assessment for in-service airplanes equipped with
phase 3 DUs using our established COS process, which determined that an
AD action was warranted for this issue. In addition, Boeing did an
independent safety review and also determined that the DU blanking was
a safety issue using its own risk assessment process.
Although various entities (operators, vendors, etc.) may have done
testing which may seem to contradict our findings, the WiFi tests
conducted during the above referenced STC project failed to meet RF
immunity level requirements. The testing that revealed the DU
susceptibility was further verified by inspection of the phase 3 DU
qualification test reports provided to the FAA by the DU manufacturer.
The intent of this AD is to eliminate this known susceptibility of
the phase 3 DUs to RF transmissions, including those from sources
outside the airplane. The phase 3 displays that failed testing did so
substantially below the RF immunity levels set forth in paragraph l of
the ``High Intensity Radiated Fields (HIRF)'' section of the preamble
to 737 Special Condition 25-ANM-132, dated September 26, 1997; and
paragraph l. of the HIRF discussion in the preamble to 777 Special
Condition 25-ANM-78, dated November 10, 1993.
We do not agree that no problems have occurred on in-service
airplanes, since the WiFi STC testing that disclosed this
susceptibility was conducted on an in-service airplane equipped with
phase 3 DUs. With respect to operational limitations providing an
acceptable level of safety, we approved certain STCs with such
limitations as a means of compliance until a permanent solution was
available. However, we intended those limitations as interim action
until permanent corrective actions for the unsafe condition became
available for the baseline airplanes. We do not consider it adequate to
leave those operating limitations in place permanently as the sole
corrective action for the unsafe condition.
Under the provisions of paragraph (h) of this AD, we will consider
requests for approval of an AMOC if sufficient data are submitted to
substantiate that the DU change is not necessary. We have not changed
this final rule in this regard.

Request To Change Compliance Time

A4A requested that we revise the compliance time in the proposed AD
(78 FR 58487, September 24, 2013) from 60 months to 72 months, and that
we recognize system redundancy when considering its compliance time
request.
A4A stated that multiple redundancies associated with the display
system are designed to assure the flight crew always has access to
critical information, and even in the event three DUs become
inoperative, all normal primary flight display, navigation display,
terrain guidance, and engine instrument information will still be
displayed to the pilot. A4A also stated that there are vastly more
affected units than were identified by the proposed AD (78 FR 58487,
September 24, 2013). A4A stated that two of its largest operators alone
account for over one thousand affected DUs. A4A contends that a 72-
month compliance time is a reasonable time to comply with the NPRM and
is an appropriate time given the risk.
We partially agree with the commenter. We agree with the
commenter's statement that there are more units and airplanes affected
than those listed in the proposed AD (78 FR 58487, September 24, 2013)
because this has now been verified with the manufacturer's service
information and comments to the NPRM. We disagree with extending the
compliance time beyond 60 months. Our risk assessment considered system
redundancy. However, along with DU susceptibility to RF transmissions,
we have also considered other risk factors such as human factors, pilot
workload, and phase of flight, etc. It is possible for all primary
flight display units to fail at once during a critical phase of flight
such as a takeoff or approach and landing. This could lead to loss of
control of the airplane at an altitude insufficient for recovery, or
controlled flight into terrain or obstacles, the availability of
standby instruments in such a situation notwithstanding.
Our compliance time is based on a detailed and in-depth risk
assessment by the FAA and Boeing that has determined that the
requirements of this AD must be accomplished within 60 months to
mitigate the unsafe condition in the interest of the safety of the
flying public. We recognize that in some cases, it may be necessary to
accomplish the AD requirements outside normal scheduled maintenance
cycles, and that some level of additional cost and/or lost revenue may
result in such cases. However, the risk assessment indicates 60 months
is an appropriate compliance time that will ensure an acceptable level
of continued operational safety for the Model 737NG and Model 777
series airplane fleets. However, according to the provisions of
paragraph (h) of this AD, we may consider requests to adjust the
compliance time if the request includes data that prove that the new
compliance time would provide an acceptable level of safety. We have
not changed this AD in this regard.

Request To Change Compliance Method

Boeing requested that we remove Boeing Special Attention Service
Bulletin 737-31-1471, dated November 29, 2012; and Boeing Special
Attention Service Bulletin 777-31-0187, dated November 29, 2012; from
the terminating action, since terminating action should include
alternate part number DUs. Or, alternatively, Boeing recommended that
operators be allowed to replace at a minimum, the phase 3 DUs and
corresponding database software with earlier or newer certified units
installed in the left outboard, right outboard and upper center DU
positions. Boeing stated that earlier versions of intermixable/
interchangeable DUs also do not exhibit HIRF susceptibility, so the
terminating action could include replacement of phase 3 DU's with
earlier certified units.
Boeing also requested that we revise the language in the NPRM (78
FR 58487, September 24, 2013) to specify that terminating action is to
remove phase 3 DUs from Model 737NG and Model 777 series airplanes,
with replacement of any other DU certified for the Model 737NG and
Model 777 series airplanes. Boeing stated that the NPRM should not
require the installation of the phase 3A DUs, but instead only require
that the phase 3 DUs be replaced or not installed on any airplane.
We partially agree with the commenter's requests. We agree that
terminating action is to replace all phase 3 DUs with certain other DUs
certified for the Model 737NG and Model 777 series airplanes. We have
revised this final rule so that it does not require the installation of
phase 3A DUs, but instead only requires that the phase 3 DUs be
replaced with the following approved DU part numbers that do not have
the unsafe condition: Phase 1, phase 2, and phase 3A DUs. Phase 1 and
phase 2 DUs do not have the RF susceptibility that has been identified
in the phase 3 DUs, are intermixable and interchangeable with the phase
3 DUs, and therefore, are an acceptable option for replacement of the
phase 3 DUs to correct the unsafe condition. The intent of this AD is
to remove all DUs with an unsafe condition and replace them with an
acceptable alternative.
We disagree with the request to remove the references to Boeing
Special Attention Service Bulletin 737-31-1471, dated November 29,
2012; and Boeing Special Attention Service Bulletin 777-31-0187, dated
November 29, 2012; from the terminating action. Installing phase 3A DUs
as specified in these service bulletins is an acceptable option for
correcting the identified unsafe condition.
We have revised paragraph (g) of this AD to require replacing phase
3 DUs with phase 1, phase 2, or phase 3A DUs.

Request To Allow DU Upgrade


Honeywell requested that we allow for phase 3 DUs to be upgraded to
phase 3A DUs, rather than replacing with new phase 3A DUs. Honeywell
stated that phase 3 DUs can be upgraded to phase 3A DUs via a
modification kit and rework process defined in service information that
has previously been provided to operators.
We agree with the commenter's request to allow for phase 3 DUs to
be upgraded to phase 3A DUs. We have removed the requirement in
paragraph (g) of this AD to replace phase 3 DUs with ``new'' phase 3A
DUs. Either new or modified phase 3A DUs may be installed.

Request To Revise Cost Estimate

Several commenters requested that we revise the cost estimate in
the NPRM (78 FR 58487, September 24, 2013). A4A requested that we
revise the cost analysis to include all affected airplanes and DUs in
the U.S. registry, and increase the per-airplane replacement time to
three hours. A4A stated that the FAA states that the NPRM affects 157
airplanes of U.S. registry, encompassing 942 DUs. A4A commented that
UAL alone operates 150 such airplanes, exposing a significant error in
estimation. A4A also stated that Honeywell indicates there are 10,100
in-service phase 3 DUs affected; and that using the NPRM figure of
$1,700 parts cost per DU ($10,200/six units per airplane), the parts
cost alone rises to $17,170,000, or more than ten times the stated
total cost of compliance. A4A also commented that while the NPRM
estimates two hours per airplane for DU replacement, one carrier
estimates three hours, a 50 percent increase in labor hours.
Ryanair requested that we review the cost of compliance. Ryanair
stated that the estimated cost of compliance for the U.S. carriers seems
to be a gross underestimate of the actual figure. Ryanair explained that it
has 707 phase 3 DUs in its fleet of 737-800s. This is approximately the
same number the FAA is assuming for the entire US fleet of Model 737NG
series airplanes.
Boeing requested that we review the estimated costs table for the
number of affected airplanes for both Model 737 and Model 777 series
airplanes; and that we include the cost of updating phase 3 DUs which
may have been installed on airplanes not delivered with phase 3 DUs as
replacement units for failed DUs, and spare phase 3 DUs provided to
airlines. Boeing explained that phase 3 DUs are interchangeable and
intermixable with earlier versions of DUs on Model 737NG and Model 777
series airplanes, and may have been installed on any Model 737NG and
Model 777 series airplane, and may be in operator spares inventory.
Boeing also stated that a review of Boeing Special Attention Service
Bulletin 737-31-1471, dated November 29, 2012; and Boeing Special
Attention Service Bulletin 777-31-0187, dated November 29, 2012; shows
an effectivity of 1,326 U.S. registered airplanes.
We partially agree with the commenters' requests. We agree with
revising the estimated U.S. fleet size in the Cost of Compliance
section in this final rule. Boeing has indicated in its comments that
the number of affected U.S. airplanes is greater than the number of
airplanes estimated in the NPRM (78 FR 58487, September 24, 2013). We
disagree with revising the estimated labor hours. The labor hour
estimate has been provided by the manufacturer. A4A's comment indicates
that only one operator estimates that the labor hour estimate should be
increased. We do not account for individual operator differences in the
calculation of total labor hour estimates. We also disagree with
considering airplanes that may have had phase 3 DUs installed after
production as we have no way of estimating how many airplanes may have
had this modification. We have changed the cost estimate in this final
rule to reflect 1,149 Model 737 airplanes and 177 Model 777 airplanes.

Comment Regarding Certification Process


Mr. Philipp Schmid commented that in today's world with more and
more transmitters in the cabin and on the ground, the FAA should have
more carefully taken into account the design and system integrations of
line replaceable units for immunity to EMI.
We acknowledge the commenter's concern. We make efforts to ensure
that systems and equipment are immune to EMI effects during
certification. We recently published rules with compliance requirements
for HIRF immunity (e.g. section 25.1317 of Title 14, Code of Federal
Regulations (14 CFR 25.1317)) (http://www.gpo.gov/fdsys/pkg/CFR-2011-
title14-vol1/pdf/CFR-2011-title14-vol1-sec25-1317.pdf). However, we
continue to conduct monitoring and surveillance of approved designs in
service and require accomplishment of corrective actions for unsafe
conditions when needed to ensure continued operational safety. This AD
accomplishes continued operational safety by addressing an identified
unsafe condition. The commenter did not request any changes to the NPRM
(78 FR 58487, September 24, 2013). We have not changed this AD in this
regard.

Clarification Regarding the Installation of Winglets

Aviation Partners Boeing (APB) stated that the installation of
winglets per Supplemental Type Certificate (STC) ST00830SE (http://
rgl.faa.gov/RegulatoryandGuidanceLibrary/
rgstc.nsf/0/
E3615811C4A7D87B86257C1C00720D67?OpenDocument&Highlight=st00830se)
does not affect the accomplishment of the manufacturer's service
instructions.
We agree with APB's statement that the installation of winglets as
specified in STC ST00830SE (http://rgl.faa.gov/
RegulatoryandGuidanceLibrary/rgstc.nsf/0/
E3615811C4A7D87B86257C1C00720D67?OpenDocument&Highlight=st00830se)
does not affect accomplishment of the requirements of this AD, and for
airplanes on which STC ST00830SE is installed, an alternative method of
compliance (AMOC) approval request to account for the installation of
that STC is not necessary to comply with the requirements of section
39.17 of the Federal Aviation Regulations (14 CFR 39.17).

Conclusion

We reviewed the relevant data, considered the comments received,
and determined that air safety and the public interest require adopting
this AD with the changes described previously and minor editorial
changes. We have determined that these minor changes:
[Agr]re consistent with the intent that was proposed in
the NPRM (78 FR 58487, September 24, 2013) for correcting the unsafe
condition; and
Do not add any additional burden upon the public than was
already proposed in the the NPRM (78 FR 58487, September 24, 2013).
We also determined that these changes will not increase the
economic burden on any operator or increase the scope of this AD.

Costs of Compliance

We estimate that this AD affects 1,326 airplanes of U.S. registry.
We estimate the following costs to comply with this AD:

Estimated Costs

Action Labor cost Parts cost Cost per product Cost on U.S.
operators
Replacement (1,149 Model 737 airplanes). 2 work-hours x $85 per hour = $170. $10,200 $10,370 $11,915,130
Replacement (177 Model 777 airplanes). 3 work-hours x $85 per hour = $255. 10,200 10,455 1,850,535

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.

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):