Published 2009-07-21 · Federal Register document E9-17118
Airworthiness Directives; Boeing Model 747-400 and -400D Series Airplanes
Publication summary
We are adopting a new airworthiness directive (AD) for certain Boeing Model 747-400 and -400D series airplanes. This AD requires installing new relays to allow the flightcrew to turn off electrical power to the in-flight entertainment (IFE) system and other non- essential passenger cabin systems through the left and right utility bus switches, and other specified actions. This AD results from an IFE systems review. We are issuing this AD to ensure that the flightcrew is able to turn off electrical power to the IFE system and other non- essential passenger cabin systems through utility bus switches in the flight compartment, in the event of smoke or fumes. The flightcrew's inability to turn off electrical power to the IFE system and other non- essential passenger cabin systems could result in the inability to control smoke or fumes in the airplane flight deck or passenger cabin during a non-normal or emergency situation.
Why this record is shown
Source: Federal Register annual FAA metadata. Acquired 2026-09-03T22:23:30.011257+00:00. The title, summary and date are source facts.
- Source revision
- federal_register_ad_metadata_2009-cb57e588bd107238
- Source row
- results[201]
- Raw source SHA-256
- cb57e588bd10723805ef0ea28ddc0685de14711012023c7e7d12178879efaeed
Final-rule publication
Recorded publication clauses
- AD identifier printed in this edition
- 2009-15-12
- Effective date printed in this edition
- 2009-08-25
Read 7 complete recorded clauses
Effective Date
Effective Date
(a) This airworthiness directive (AD) is effective August 25,
2009.
Exact source excerpt. Text positions 15792–15882, end exclusive, in the original decoded publication. SHA-256: a880803162ecf448d0fdfa79ac6d5529539e9162647a5157491831d058afaf41
Affected ADs
Affected ADs
(b) None.
Exact source excerpt. Text positions 15882–15911, end exclusive, in the original decoded publication. SHA-256: 027fbc44617399472b6ac4741da3aee18448654374228bcf4fe3f01df6b1539b
Applicability wording · Applicability
Applicability
(c) This AD applies to Boeing Model 747-400 and -400D series
airplanes, certificated in any category; as identified in Boeing
Service Bulletin 747-24-2246, dated October 6, 2005.
[[Page 35792]]
Exact source excerpt. Text positions 15911–16128, end exclusive, in the original decoded publication. SHA-256: e12062912d951b126cc7ce932e045214a7ad60f28451c09b551461d75b0af17c
Unsafe Condition
Unsafe Condition
(d) This AD results from an in-flight entertainment (IFE)
systems review. We are issuing this AD to ensure that the flightcrew
is able to turn off electrical power to the IFE system and other
non-essential passenger cabin systems through utility bus switches
in the flight compartment, in the event of smoke or fumes. The
flightcrew's inability to turn off electrical power to the IFE
system and other non-essential passenger cabin systems could result
in the inability to control smoke or fumes in the airplane flight
deck or passenger cabin during a non-normal or emergency situation.
Exact source excerpt. Text positions 16128–16746, end exclusive, in the original decoded publication. SHA-256: 54d9fd9a4ac950e0b9c5e0a9b59a34074c33f0452d874df4cbe8056308b9555f
Compliance
Compliance
(e) You are responsible for having the actions required by this
AD performed within the compliance times specified, unless the
actions have already been done.
Exact source excerpt. Text positions 16746–16924, end exclusive, in the original decoded publication. SHA-256: 64a7a1579f37f56eafecd0aeb3c528e7c89f6292ed0cb53091423917642d5847
Install New Relays
Install New Relays
(f) Within 60 months after the effective date of this AD,
install new relays to allow the flightcrew to turn off electrical
power to the IFE system and other non-essential passenger cabin
systems through the left and right utility bus switches and do all
other specified actions as applicable, by accomplishing all the
applicable actions specified in the Accomplishment Instructions of
Boeing Service Bulletin 747-24-2246, dated October 6, 2005. The
other specified actions must be done before further flight after
installing the new relays.
Alternative Methods of Compliance (AMOCs)
(g)(1) The Manager, Seattle Aircraft Certification Office (ACO),
FAA, ATTN: Joe Salameh, Aerospace Engineer, Systems and Equipment
Branch, ANM-130S, FAA, Seattle ACO, 1601 Lind Avenue, SW., Renton,
Washington 98057-3356; telephone 425-917-6454; fax 425-917-6590; has
the authority to approve AMOCs for this AD, if requested using the
procedures found in 14 CFR 39.19.
(2) To request a different method of compliance or a different
compliance time for this AD, follow the procedures in 14 CFR 39.19.
Before using any approved AMOC on any airplane to which the AMOC
applies, notify your principal maintenance inspector (PMI) or
principal avionics inspector (PAI), as appropriate, or lacking a
principal inspector, your local Flight Standards District Office.
The AMOC approval letter must specifically reference this AD.
Exact source excerpt. Text positions 16924–18381, end exclusive, in the original decoded publication. SHA-256: e2b2a9725329f15d2e2b76eaec9449696cc9e0f3e3e2263e9157753377b8889e
Material Incorporated by Reference
Material Incorporated by Reference
(h) You must use Boeing Service Bulletin 747-24-2246, dated
October 6, 2005, to do the actions required by this AD, unless the
AD specifies otherwise.
(1) The Director of the Federal Register approved the
incorporation by reference of this service information under 5
U.S.C. 552(a) and 1 CFR part 51.
(2) For service information identified in this AD, contact
Boeing Commercial Airplanes, Attention: Data & Services Management,
P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone
206-544-5000, extension 1; fax 206-766-5680; e-mail
[email protected]; Internet https://www.myboeingfleet.com.
(3) You may review copies of the service information at the 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 or 425-227-1152.
(4) You may also review copies of the 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/code_of_federal_regulations/ibr_locations.html.
Exact source excerpt. Text positions 18381–19629, end exclusive, in the original decoded publication. SHA-256: e48b8ce9374678e5b7ce8037e78785d1607ca5f6e0926ccced056d0c01500dec
No replacement link has been established from this edition. The complete historical rule chain and current legal effect remain unknown.
Find all recorded historical references to AD 2009-15-12 · 0 printed reference observations in this pinned collection.
These are observations from one dated publication. Current legal status is unknown; aircraft applicability, installed configuration, compliance and burden require separate evidence. Missing or unparsed conditions remain unknown.
Why these observations are shown
They were extracted offline from the same immutable official HTML source as the complete recorded text. The dated source wording, original text coordinates and exact quote digests are retained. PDF/text agreement and current regulatory effect have not been qualified.
Observation revision: whole-ad-publication-clause-observations-1.0.1. Text SHA-256: d1a28acbefea7bb4fd7d3922283dcc0b667a69116db7d701d030e79abb949e76. Source manifest: 44ed81ebf20e4b2a9be62b8bb6c636c16357984f2648858b01dea9f42a06c711.
Official source · 2009-07-21
Publication text
This is the complete recorded text of this dated publication.
Current legal effect is unknown. Aircraft applicability, installed configuration and compliance require separate evidence. PDF/text agreement has not been evaluated.
Read the complete official publication text
[Federal Register Volume 74, Number 138 (Tuesday, July 21, 2009)]
[Rules and Regulations]
[Pages 35789-35792]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E9-17118]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2007-28988; Directorate Identifier 2007-NM-047-AD;
Amendment 39-15975; AD 2009-15-12]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 747-400 and -400D Series
Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: We are adopting a new airworthiness directive (AD) for certain
Boeing Model 747-400 and -400D series airplanes. This AD requires
installing new relays to allow the flightcrew to turn off electrical
power to the in-flight entertainment (IFE) system and other non-
essential passenger cabin systems through the left and right utility
bus switches, and other specified actions. This AD results from an IFE
systems review. We are issuing this AD to ensure that the flightcrew is
able to turn off electrical power to the IFE system and other non-
essential passenger cabin systems through utility bus switches in the
flight compartment, in the event of smoke or fumes. The flightcrew's
inability to turn off electrical power to the IFE system and other non-
essential passenger cabin systems could result in the inability to
control smoke or fumes in the airplane flight deck or passenger cabin
during a non-normal or emergency situation.
DATES: This AD is effective August 25, 2009.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of August 25,
2009.
ADDRESSES: For service information identified in this AD, contact
Boeing Commercial Airplanes, Attention: Data & Services Management,
P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-
544-5000, extension 1; fax 206-766-5680; e-mail [email protected];
Internet https://www.myboeingfleet.com.
[[Page 35790]]
Examining the AD Docket
You may examine the AD docket on the Internet at http://www.regulations.gov; 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 (telephone 800-647-5527) is the Document 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: Joe Salameh, Aerospace Engineer,
Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-
3356; telephone 425-917-6454; fax 425-917-6590.
SUPPLEMENTARY INFORMATION:
Discussion
We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR
part 39 to include an airworthiness directive (AD) that would apply to
certain Boeing Model 747-400 and -400D series airplanes. That NPRM was
published in the Federal Register on August 16, 2007 (72 FR 45968).
That NPRM proposed to require installing new relays to allow the
flightcrew to turn off electrical power to the in-flight entertainment
(IFE) system and other non-essential passenger cabin systems through
the left and right utility bus switches, and other specified actions.
Comments
We gave the public the opportunity to participate in developing
this AD. We considered the comments received from the three commenters.
Support for the NPRM
Inflight Canada (IFC) strongly supports the intent of the NPRM.
Request To Clarify Service Bulletin Instructions
Boeing requests that we clarify, in the ``Relevant Service
Information'' section of the NPRM, that Boeing Service Bulletin 747-24-
2246, dated October 6, 2005, provides procedures for turning off 28 VDC
power to the IFE system. Boeing states that all Model 747-400 series
airplanes have 115 VAC control, and that representing the proposed
actions as addressing electrical power, in general, might be misleading
to operators regarding the scope of the action.
We agree to provide clarification. We understand that operators are
able to turn off 115 VAC power under the existing configuration for
Model 747 series airplanes, and that Boeing Service Bulletin 747-24-
2246, dated October 6, 2005, provides changes to also allow for turning
off 28 VDC power. Therefore, the wording of the NPRM is appropriate and
not misleading, since the intent of this AD is to ensure that all
electrical power is removed from the affected systems through the use
of the right and left utility bus switches. No change to the AD is
necessary in this regard.
Request To Clarify Instructions for Airplanes Modified After Delivery
Boeing requests that we clarify, in the ``Relevant Service
Information'' section of the NPRM, that instructions in Boeing service
bulletins are based upon the delivered product configuration. Boeing
states that it is not obvious to operators that post-production
modifications to the IFE system might require an alternative method of
compliance (AMOC) to comply with the requirements of the AD.
We agree that operators might not be able to accomplish the
requirements of this AD on airplanes that have been modified or altered
after airplane delivery. Section 39.17 of the Federal Aviation
Regulations (14 CFR 39.17) specifically addresses this situation. If a
change in a product affects one's ability to accomplish the actions
required by an AD, then a request for FAA approval of an AMOC
addressing that configuration must be submitted in accordance with the
procedures specified in paragraph (g) of this AD. According to 14 CFR
39.17, the request should include the specific actions that are
proposed to address the unsafe condition, unless one can show that the
change eliminated the unsafe condition. No change to the AD is
necessary in this regard.
Request To Remove Certain Airplanes From the Applicability
Lufthansa states that it has installed two additional Heath Techna
power distribution panels (P94 and P9100) on all of its affected
airplanes, in accordance with Supplemental Type Certificate (STC)
ST01507SE, issued February 11, 2005, amended September 7, 2006.
Lufthansa states that, on these modified airplanes, power can be turned
off by right and left utility bus switches located in the cockpit.
Lufthansa also states that, additionally, the cabin crew is able to
turn off power to the IFE and passenger seats using a master switch
located in the purser station of the cabin. Since the modification
addresses the intent of the NPRM, Lufthansa has asked Boeing to remove
all of Lufthansa's airplanes from the effectivity of Boeing Service
Bulletin 747-24-2246, dated October 6, 2005. We refer to that service
bulletin for the applicability of this AD.
We infer that Lufthansa requests that we remove airplanes modified
in accordance with STC ST01507SE from the applicability of this AD. We
disagree with revising the applicability of this AD because we have
determined that, based upon the delivered airplane configuration, the
unsafe condition of this AD applies to the airplanes identified in the
effectivity of Boeing Service Bulletin 747-24-2246, dated October 6,
2005. STC ST01507SE, at the time of its issuance, was not evaluated as
an AMOC to the requirements of this AD. The design and installation
aspects of the STC must be reviewed under an AMOC request submitted by
either the STC applicant or the operator. Under the provisions of
paragraph (g) of this AD, we will consider requests for approval of an
AMOC if sufficient data are submitted to substantiate that the design
change would provide an acceptable level of safety. We have not changed
the AD in this regard.
Recommendation To Consider This AD an Interim Action
IFC recommends that we consider the requirements of this AD an
interim action. IFC states the final action for eliminating the unsafe
condition should be to move the components and wire bundles from the
cabin area to areas where they will not be subjected to damage and
abuse. IFC states that the cabin sidewalls and the area under the cabin
floor offer much safer environments for these items.
We disagree with considering this AD an interim action. The intent
of the AD is to address the unsafe condition, not to provide design
guidelines for installation of the IFE system. We have determined that
the requirements of this AD adequately address the unsafe condition.
Should new reports or data arise that show that the unsafe condition
has not been adequately addressed by the requirements of this AD, we
could consider further rulemaking. No change to the AD is necessary in
this regard.
Recommendation To Remove Power From All Components in the Cabin
IFC recommends that the requirement to be able to remove power from
the IFE system be expanded to include all components using power in the
passenger cabin. IFC states that, in most cases, the In Seat Power
Systems (ISPS) and seat adjustment systems carry much
[[Page 35791]]
higher power loads than do the IFE components.
We disagree that the scope of the AD needs to be expanded because
the ISPS and seat adjustment systems are addressed already as other
non-essential cabin systems in Boeing Service Bulletin 747-24-2246,
dated October 6, 2005. No change to the AD is necessary in this regard.
Recommendation To Locate Primary Switch in the Passenger Cabin
IFC recommends that the primary switch to isolate the IFE system
and other non-essential cabin systems be located in the cabin, rather
than in the cockpit. IFC states that, in most cases, the cabin crew
will be the first to notice a problem, and that the additional time
needed to notify the flightcrew will allow the problem to worsen if not
immediately addressed by the trained cabin crew. IFC states that, if
desired, a secondary switch could also be located in the cockpit.
We disagree because Boeing's design approach adequately addresses
the unsafe condition; the flightcrew can shut off power to any non-
essential system in the event of smoke or fire in the flight deck or
passenger cabin. However, under the provisions of paragraph (g) of this
AD, we will consider requests for approval of an AMOC if sufficient
data are submitted to substantiate that the design change would provide
an acceptable level of safety. We have not changed the AD in this
regard.
Recommendation to Automatically Turn Off Power in an Emergency
IFC recommends that the system, which will provide the IFE shut-off
capability, also be required to automatically turn off power in the
event of certain emergencies, such as deployment of oxygen masks or
loss of a generator. IFC states that this capability would allow the
flightcrew and cabin crew to perform more important tasks without
having to be concerned with turning off power to the IFE system.
We disagree with requiring the system to automatically turn off
power to the IFE system and other non-essential cabin systems in the
event of certain emergencies because, currently, there is no regulatory
requirement to have power turned off automatically. We are issuing this
AD to address a specific unsafe condition, and the areas discussed by
IFC fall outside the requirements of this AD. We have not changed the
AD in this regard.
Recommendation To Allow Operators To Develop Other Solutions
IFC states that Boeing Service Bulletin 747-24-2246, dated October
6, 2005, which is referenced as the only acceptable means of complying
with the intent of the NPRM, provides only limited protection from the
myriad of electrical hazards in the cabin. IFC recommends that we
establish the desired functionality of a system for dealing with the
electrical hazards, and then allow operators to develop workable
solutions using these in combination with other designs to meet the
requirements.
We disagree because we are issuing this AD to address a specific
unsafe condition, and we have determined that the service information
that is currently available adequately addresses that unsafe condition.
However, under the provisions of paragraph (g) of this AD, we will
consider requests for approval of an AMOC if sufficient data are
submitted to substantiate that the design change would provide an
acceptable level of safety. We have not changed the AD in this regard.
Conclusion
We reviewed the relevant data, considered the comments received,
and determined that air safety and the public interest require adopting
the AD as proposed.
Costs of Compliance
There are about 490 airplanes of the affected design in the
worldwide fleet. This AD affects about 62 airplanes of U.S. registry.
The required actions take about 123 work hours per airplane, at an
average labor rate of $80 per work hour. Required parts cost between
$9,412 and $11,936 per airplane. Based on these figures, the estimated
cost of the AD for U.S. operators is up to $1,350,112, or up to $21,776
per airplane.
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), 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.
You can find our regulatory evaluation and the estimated costs of
compliance in the AD Docket.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
0
Accordingly, under the authority delegated to me by the Administrator,
the FAA amends 14 CFR part 39 as follows:
PART 39--AIRWORTHINESS DIRECTIVES
0
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]
0
2. The FAA amends Sec. 39.13 by adding the following new AD:
2009-15-12 Boeing: Amendment 39-15975. Docket No. FAA-2007-28988;
Directorate Identifier 2007-NM-047-AD.
Effective Date
(a) This airworthiness directive (AD) is effective August 25,
2009.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Boeing Model 747-400 and -400D series
airplanes, certificated in any category; as identified in Boeing
Service Bulletin 747-24-2246, dated October 6, 2005.
[[Page 35792]]
Unsafe Condition
(d) This AD results from an in-flight entertainment (IFE)
systems review. We are issuing this AD to ensure that the flightcrew
is able to turn off electrical power to the IFE system and other
non-essential passenger cabin systems through utility bus switches
in the flight compartment, in the event of smoke or fumes. The
flightcrew's inability to turn off electrical power to the IFE
system and other non-essential passenger cabin systems could result
in the inability to control smoke or fumes in the airplane flight
deck or passenger cabin during a non-normal or emergency situation.
Compliance
(e) You are responsible for having the actions required by this
AD performed within the compliance times specified, unless the
actions have already been done.
Install New Relays
(f) Within 60 months after the effective date of this AD,
install new relays to allow the flightcrew to turn off electrical
power to the IFE system and other non-essential passenger cabin
systems through the left and right utility bus switches and do all
other specified actions as applicable, by accomplishing all the
applicable actions specified in the Accomplishment Instructions of
Boeing Service Bulletin 747-24-2246, dated October 6, 2005. The
other specified actions must be done before further flight after
installing the new relays.
Alternative Methods of Compliance (AMOCs)
(g)(1) The Manager, Seattle Aircraft Certification Office (ACO),
FAA, ATTN: Joe Salameh, Aerospace Engineer, Systems and Equipment
Branch, ANM-130S, FAA, Seattle ACO, 1601 Lind Avenue, SW., Renton,
Washington 98057-3356; telephone 425-917-6454; fax 425-917-6590; has
the authority to approve AMOCs for this AD, if requested using the
procedures found in 14 CFR 39.19.
(2) To request a different method of compliance or a different
compliance time for this AD, follow the procedures in 14 CFR 39.19.
Before using any approved AMOC on any airplane to which the AMOC
applies, notify your principal maintenance inspector (PMI) or
principal avionics inspector (PAI), as appropriate, or lacking a
principal inspector, your local Flight Standards District Office.
The AMOC approval letter must specifically reference this AD.
Material Incorporated by Reference
(h) You must use Boeing Service Bulletin 747-24-2246, dated
October 6, 2005, to do the actions required by this AD, unless the
AD specifies otherwise.
(1) The Director of the Federal Register approved the
incorporation by reference of this service information under 5
U.S.C. 552(a) and 1 CFR part 51.
(2) For service information identified in this AD, contact
Boeing Commercial Airplanes, Attention: Data & Services Management,
P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone
206-544-5000, extension 1; fax 206-766-5680; e-mail
[email protected]; Internet https://www.myboeingfleet.com.
(3) You may review copies of the service information at the 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 or 425-227-1152.
(4) You may also review copies of the 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/code_of_federal_regulations/ibr_locations.html.
Issued in Renton, Washington, on July 6, 2009.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E9-17118 Filed 7-20-09; 8:45 am]
BILLING CODE 4910-13-P
Why this text is shown
The complete text was extracted from the official GovInfo HTML edition for this publication. Acquired 2026-10-09T03:21:29.317459+00:00. Text extraction preserves the recorded source wording; it does not determine current requirements.
Open the captured official edition
- Source SHA-256
- 933eba7d5bad2d78bcfa207d2f9c2126323708441bc56d49ce8c4cbaade11955
- Text SHA-256
- d1a28acbefea7bb4fd7d3922283dcc0b667a69116db7d701d030e79abb949e76
Return to the full metadata catalog · Search complete publication text · Explore retained publication text and evidence
Coverage and limits
These are dated publication metadata, recorded clauses and literal source observations. Word, model-label, header and reference matches do not establish current legal effect, manufacturer/model identity, aircraft applicability, installed configuration or compliance.
The collection uses 33 explicit annual source snapshots. Source captures and operative-text qualifications have separate states. Missing information remains unknown.