Published 2024-09-16 · Federal Register document 2024-20844
Airworthiness Directives; Airbus Helicopters
Publication summary
The FAA is adopting a new airworthiness directive (AD) for all Airbus Helicopters Model SA330J helicopters. This AD was prompted by a report of a main rotor gearbox (MGB) flange assembly coupling (coupling) that was incorrectly assembled. This AD requires a one-time visual inspection to determine correct assembly of each sliding flange installed on each MGB coupling, and if necessary, further corrective actions. This AD also prohibits installing certain MGB couplings or any MGB equipped with certain MGB couplings on any helicopter. These requirements are specified in a European Union Aviation Safety Agency (EASA) AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products.
Why this record is shown
Source: Federal Register annual FAA metadata. Acquired 2026-09-03T22:24:17.530091+00:00. The title, summary and date are source facts.
- Source revision
- federal_register_ad_metadata_2024-766a4e72ab891edd
- Source row
- results[186]
- Raw source SHA-256
- 766a4e72ab891edde7194caaae181bc9ea3fd0d54e65313e290f97067e3b7c5a
Final-rule publication
Recorded publication clauses
- AD identifier printed in this edition
- 2024-16-05
- Effective date printed in this edition
- 2024-10-21
Read 13 complete recorded clauses
Effective Date
(a) Effective Date
This airworthiness directive (AD) is effective October 21, 2024.
Exact source excerpt. Text positions 9915–10005, end exclusive, in the original decoded publication. SHA-256: 0b66eba1237b975b7eb628ccd672a1cfd24c409a4ea93aa127bf1f2bbb0f9a88
Affected ADs
(b) Affected ADs
None.
Exact source excerpt. Text positions 10005–10034, end exclusive, in the original decoded publication. SHA-256: 871a4afc60ceeae06e8010585055188633d616078500c45937092bfe892239c0
Applicability wording · Applicability
(c) Applicability
This AD applies to all Airbus Helicopters Model SA330J
helicopters, certificated in any category.
Exact source excerpt. Text positions 10034–10157, end exclusive, in the original decoded publication. SHA-256: c0059961b8bdc5d146f7c633534a65e8f8026e2b0f009fb26fe02db6303c00ec
Subject
(d) Subject
Joint Aircraft System Component (JASC) Code: 6320, Main rotor
gearbox.
Exact source excerpt. Text positions 10157–10247, end exclusive, in the original decoded publication. SHA-256: ddefb993c3e7e5fbac38b677fce4d5e3086d177c91f07384f5757ecf0c02d539
Unsafe Condition
(e) Unsafe Condition
This AD was prompted by a report of an incorrectly assembled
main rotor gearbox (MGB) flange assembly coupling (coupling). The
FAA is issuing this AD to detect and address incorrectly assembled
MGB couplings. The unsafe condition, if not addressed, could result
in loss of the drive transmission from the left-hand or right-hand
engine, and subsequent loss of control of the helicopter.
Exact source excerpt. Text positions 10247–10666, end exclusive, in the original decoded publication. SHA-256: 5587a65669f69c33d18960a8ba1d03a94c606a810350dfba3c01fa06d3da1ccc
Compliance
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
Exact source excerpt. Text positions 10666–10768, end exclusive, in the original decoded publication. SHA-256: 00fbfa31932483f627d0ce0a11cbd2e35e15d9231842b91ac85623ce533912d3
Requirements
(g) Requirements
Except as specified in paragraphs (h) and (i) of this AD: Comply
with all required actions and compliance times specified in, and in
accordance with, European Union Aviation Safety Agency (EASA) AD
2022-0140, dated July 7, 2022 (EASA AD 2022-0140).
[[Page 75472]]
Exact source excerpt. Text positions 10768–11059, end exclusive, in the original decoded publication. SHA-256: b1543b6009de9b31b424543a8af4adb5b5beef55b0f9a95a838d0e8d3e160b9c
Exceptions to EASA AD 2022-0140
(h) Exceptions to EASA AD 2022-0140
(1) Where EASA AD 2022-0140 requires compliance in terms of
flight hours, this AD, requires using hours time-in-service.
(2) Where EASA AD 2022-0140 refers to its effective date, this
AD requires using the effective date of this AD.
(3) Where paragraph (1) of EASA AD 2022-0140 states, ``in
accordance with the instructions of the ASB,'' for this AD, replace
that text with ``in accordance with the Accomplishment Instructions,
paragraph 3.B.2.b. of the ASB, except you are not required to comply
with paragraph 3.B.2.c.''
(4) Where paragraph (2) of EASA AD 2022-0140 states to ``replace
the affected part with a serviceable part, in accordance with the
instructions of the ASB'' for this AD, replace that text with
``remove the affected part, as defined in EASA AD 2022-0140, from
service and replace it with a serviceable part, as defined in EASA
AD 2022-0140, in accordance with the Accomplishment Instructions,
paragraph 3.B.2.d. of the ASB, except you are not required to send
an affected part to Airbus Helicopters or comply with paragraphs 2.D
or 3.B.3 of the ASB.''
(5) Where the service information referenced in EASA AD 2022-
0140 specifies ``install a flange assy coupling (1) correctly
assembled,'' for this AD, replace that text with ``install a
correctly assembled MGB coupling.''
(6) This AD does not adopt the ``Remarks'' section of EASA AD
2022-0140.
Exact source excerpt. Text positions 11059–12506, end exclusive, in the original decoded publication. SHA-256: 8263e7980749f502c6f1c295fd7ee4b2c797f21c744ef0f13ebda62ad3fec7c3
No Reporting or Return of Parts
(i) No Reporting or Return of Parts
Although the service information referenced in EASA AD 2022-0140
specifies to submit certain information and return parts to the
manufacturer, this AD does not require those actions.
Exact source excerpt. Text positions 12506–12733, end exclusive, in the original decoded publication. SHA-256: bc10ce06fbbfbef915085429170da6360061069e30dcf1cd17339b168d60bc2b
Special Flight Permits
(j) Special Flight Permits
Special flight permits may be issued in accordance with 14 CFR
21.197 and 21.199 in order to fly to a maintenance area to perform
the required actions in this AD, provided there are no passengers
onboard.
Exact source excerpt. Text positions 12733–12974, end exclusive, in the original decoded publication. SHA-256: f9de04ccef36bea8ae0d3c62dda27bcacce6f18eeb0b746b0bc68d83482fc5fc
Alternative Methods of Compliance (AMOCs)
(k) Alternative Methods of Compliance (AMOCs)
(1) The Manager, West Certification Branch, FAA, has the
authority to approve AMOCs for this AD, if requested using the
procedures 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 certification office, send it to the
attention of the person identified in paragraph (l) of this AD.
Information may be emailed to [email protected].
(2) Before using any approved AMOC, notify your appropriate
principal inspector, or lacking a principal inspector, the manager
of the local flight standards district office/certificate holding
district office.
Exact source excerpt. Text positions 12974–13746, end exclusive, in the original decoded publication. SHA-256: 771d262374fb93b32238c048ee6b590f9a395afca643e5c391a1a5fe8cb4ab9e
Related Information
(l) Related Information
For more information about this AD, contact Hal Jensen, Aviation
Safety Engineer, FAA; 3960 Paramount Boulevard, Lakewood, CA 90712;
telephone (303) 342-1080; email [email protected].
Exact source excerpt. Text positions 13746–13962, end exclusive, in the original decoded publication. SHA-256: a50fc1b22fc6da92b7ec3c976c43e3b4e51b916cb4a703bba7ae8ed00bc26c7a
Material Incorporated by Reference
(m) Material Incorporated by Reference
(1) The Director of the Federal Register approved the
incorporation by reference of the material listed in this paragraph
under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) You must use this material as applicable to do the actions
required by this AD, unless the AD specifies otherwise.
(i) European Union Aviation Safety Agency (EASA) AD 2022-0140,
dated July 7, 2022.
(ii) [Reserved]
(3) For EASA material identified in this AD, contact EASA,
Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; telephone +49 221
8999 000; email [email protected]; internet easa.europa.eu. You may
find the EASA material on the EASA website at ad.easa.europa.eu.
(4) You may view this material at the FAA, Office of the
Regional Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 6N-
321, Fort Worth, TX 76177. For information on the availability of
this material at the FAA, call (817) 222-5110.
(5) You may view this material at the National Archives and
Records Administration (NARA). For information on the availability
of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email [email protected].
Exact source excerpt. Text positions 13962–15157, end exclusive, in the original decoded publication. SHA-256: 0a007edea4f0dde341e59007f22bce04498902169b55b5cfd725b2de86abe5e0
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 2024-16-05 · 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: 5195040cc067a3f7f4948dcebd6beaa84f0acde59f76f1f176c6d4ec3e43790e. Source manifest: d217dedac1eb5ee3026379b21b150f39591a90c88b804fcdc174076eaa6858d5.
Official source · 2024-09-16
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 89, Number 179 (Monday, September 16, 2024)]
[Rules and Regulations]
[Pages 75470-75472]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-20844]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2024-1291; Project Identifier MCAI-2022-00901-R;
Amendment 39-22811; AD 2024-16-05]
RIN 2120-AA64
Airworthiness Directives; Airbus Helicopters
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all
Airbus Helicopters Model SA330J helicopters. This AD was prompted by a
report of a main rotor gearbox (MGB) flange assembly coupling
(coupling) that was incorrectly assembled. This AD requires a one-time
visual inspection to determine correct assembly of each sliding flange
installed on each MGB coupling, and if necessary, further corrective
actions. This AD also prohibits installing certain MGB couplings or any
MGB equipped with certain MGB couplings on any helicopter. These
requirements are specified in a European Union Aviation Safety Agency
(EASA) AD, which is incorporated by reference. The FAA is issuing this
AD to address the unsafe condition on these products.
DATES: This AD is effective October 21, 2024.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of October 21,
2024.
ADDRESSES:
AD Docket: You may examine the AD docket at regulations.gov under
Docket No. FAA-2024-1291; 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 EASA AD, any comments received,
and other information. The 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.
Material Incorporated by Reference:
<bullet> For EASA material identified in this AD, contact EASA,
Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; telephone +49 221 8999
000; email [email protected]; internet easa.europa.eu. You may find
the EASA material on the EASA website at ad.easa.europa.eu.
<bullet> You may view this material at the FAA, Office of the
Regional Counsel, Southwest Region, 10101 Hillwood Parkway, Room 6N-
321, Fort Worth, TX 76177. For information on the availability of this
material at the FAA, call (817) 222-5110. It is also available at
regulations.gov under Docket No. FAA-2024-1291.
Other Related Service Information: For Airbus Helicopters material,
contact Airbus Helicopters, 2701 North Forum Drive, Grand Prairie, TX
75052; phone (972) 641-0000 or (800) 232-0323; fax (972) 641-3775; or
at airbus.com/en/products-services/helicopters/hcare-services/airbusworld.
FOR FURTHER INFORMATION CONTACT: Hal Jensen, Aviation Safety Engineer,
FAA; 3960 Paramount Boulevard, Lakewood, CA 90712; telephone (303) 342-
1080; email [email protected].
SUPPLEMENTARY INFORMATION:
Background
EASA, which is the Technical Agent for the Member States of the
European Union, has issued EASA AD 2022-0140, dated July 7, 2022 (EASA
AD 2022-0140), to correct an unsafe condition on Airbus Helicopters
Model SA 330 J helicopters, all serial numbers.
The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 by adding an AD that would apply to Airbus Helicopters
Model SA330J helicopters, certificated in any category. The NPRM
published in the Federal Register on May 15, 2024 (89 FR 42397). The
NPRM was prompted by a report of an incorrectly assembled MGB coupling
part number (P/N) 330A32-9392-01 which was installed in the reverse
position, deviating from the assembly instructions.
In the NPRM, the FAA proposed to require accomplishing the actions
specified in EASA AD 2022-0140, as incorporated by reference, except
for any differences identified as exceptions in the regulatory text of
this AD and except as discussed under ``Differences Between this AD and
the EASA AD.'' This condition, which if not addressed, could lead to
loss of the drive transmission from the left-hand or right-hand engine,
and subsequent loss of control of the helicopter. The FAA is issuing
this AD to address the unsafe condition on these products.
[[Page 75471]]
You may examine EASA AD 2022-0140 in the AD docket at
regulations.gov under Docket No. FAA-2024-1291.
Discussion of Final Airworthiness Directive
Comments
The FAA received no comments on the NPRM or on the determination of
the costs.
Conclusion
These helicopters have been approved by EASA and are approved for
operation in the United States. Pursuant to the FAA's bilateral
agreement with the European Union, EASA has notified the FAA about the
unsafe condition described in its AD. The FAA reviewed the relevant
data and determined that air safety requires adopting this AD as
proposed. Accordingly, the FAA is issuing this AD to address the unsafe
condition on these helicopters.
Material Incorporated by Reference Under 1 CFR Part 51
EASA AD 2022-0140 requires a one-time inspection of the left-hand
and right-hand MGB coupling P/N 330A32-9392-01 for correct assembly. If
any MGB coupling is incorrectly assembled, EASA AD 2022-0140 requires
replacing an affected MGB coupling with a serviceable MGB coupling.
EASA AD 2022-0140 also prohibits installing an affected MGB coupling or
an MGB equipped with an affected coupling installed, on any helicopter
unless it has passed inspection requirements.
This material 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.
Other Related Material
The FAA also reviewed Airbus Helicopters Alert Service Bulletin No.
SA330-65.140, Revision 0, dated June 30, 2022, which specifies
procedures for inspecting the assembly of the MGB coupling by ensuring
the sliding flange is correctly assembled and there is no presence of
embossments. This material also specifies procedures for replacing an
affected MGB coupling with a correctly assembled MGB coupling and
instructions to send affected parts to Airbus Helicopters.
Differences Between This AD and the EASA AD
If any incorrectly assembled MGB coupling is found during the
inspection, EASA AD 2022-0140 requires replacing each affected part
with a serviceable part, whereas this AD requires removing each
affected part from service and replacing it with a serviceable part, as
defined in EASA AD 2022-0140.
Service information referenced in EASA AD 2022-0140 specifies
reporting certain information and sending affected parts to Airbus
Helicopters, whereas this AD does not require sending information or
parts to Airbus Helicopters.
Costs of Compliance
The FAA estimates that this AD affects 7 helicopters of U.S.
registry. Labor rates are estimated at $85 per work-hour. Based on
these numbers, the FAA estimates the following costs to comply with
this AD.
Visually inspecting each MGB coupling will take approximately 4
work-hours for an estimated cost of $340 per helicopter and up to
$2,380 for the U.S. fleet.
If required, removing and replacing the MGB coupling will take
approximately 8 work-hours and parts will cost approximately $23,215
for an estimated cost of $23,895 per helicopter.
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.
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) Will not affect intrastate aviation in Alaska, 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.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
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
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 airworthiness
directive:
2024-16-05 Airbus Helicopters: Amendment 39-22811; Docket No. FAA-
2024-1291; Project Identifier MCAI-2022-00901-R.
(a) Effective Date
This airworthiness directive (AD) is effective October 21, 2024.
(b) Affected ADs
None.
(c) Applicability
This AD applies to all Airbus Helicopters Model SA330J
helicopters, certificated in any category.
(d) Subject
Joint Aircraft System Component (JASC) Code: 6320, Main rotor
gearbox.
(e) Unsafe Condition
This AD was prompted by a report of an incorrectly assembled
main rotor gearbox (MGB) flange assembly coupling (coupling). The
FAA is issuing this AD to detect and address incorrectly assembled
MGB couplings. The unsafe condition, if not addressed, could result
in loss of the drive transmission from the left-hand or right-hand
engine, and subsequent loss of control of the helicopter.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Requirements
Except as specified in paragraphs (h) and (i) of this AD: Comply
with all required actions and compliance times specified in, and in
accordance with, European Union Aviation Safety Agency (EASA) AD
2022-0140, dated July 7, 2022 (EASA AD 2022-0140).
[[Page 75472]]
(h) Exceptions to EASA AD 2022-0140
(1) Where EASA AD 2022-0140 requires compliance in terms of
flight hours, this AD, requires using hours time-in-service.
(2) Where EASA AD 2022-0140 refers to its effective date, this
AD requires using the effective date of this AD.
(3) Where paragraph (1) of EASA AD 2022-0140 states, ``in
accordance with the instructions of the ASB,'' for this AD, replace
that text with ``in accordance with the Accomplishment Instructions,
paragraph 3.B.2.b. of the ASB, except you are not required to comply
with paragraph 3.B.2.c.''
(4) Where paragraph (2) of EASA AD 2022-0140 states to ``replace
the affected part with a serviceable part, in accordance with the
instructions of the ASB'' for this AD, replace that text with
``remove the affected part, as defined in EASA AD 2022-0140, from
service and replace it with a serviceable part, as defined in EASA
AD 2022-0140, in accordance with the Accomplishment Instructions,
paragraph 3.B.2.d. of the ASB, except you are not required to send
an affected part to Airbus Helicopters or comply with paragraphs 2.D
or 3.B.3 of the ASB.''
(5) Where the service information referenced in EASA AD 2022-
0140 specifies ``install a flange assy coupling (1) correctly
assembled,'' for this AD, replace that text with ``install a
correctly assembled MGB coupling.''
(6) This AD does not adopt the ``Remarks'' section of EASA AD
2022-0140.
(i) No Reporting or Return of Parts
Although the service information referenced in EASA AD 2022-0140
specifies to submit certain information and return parts to the
manufacturer, this AD does not require those actions.
(j) Special Flight Permits
Special flight permits may be issued in accordance with 14 CFR
21.197 and 21.199 in order to fly to a maintenance area to perform
the required actions in this AD, provided there are no passengers
onboard.
(k) Alternative Methods of Compliance (AMOCs)
(1) The Manager, West Certification Branch, FAA, has the
authority to approve AMOCs for this AD, if requested using the
procedures 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 certification office, send it to the
attention of the person identified in paragraph (l) of this AD.
Information may be emailed to [email protected].
(2) Before using any approved AMOC, notify your appropriate
principal inspector, or lacking a principal inspector, the manager
of the local flight standards district office/certificate holding
district office.
(l) Related Information
For more information about this AD, contact Hal Jensen, Aviation
Safety Engineer, FAA; 3960 Paramount Boulevard, Lakewood, CA 90712;
telephone (303) 342-1080; email [email protected].
(m) Material Incorporated by Reference
(1) The Director of the Federal Register approved the
incorporation by reference of the material listed in this paragraph
under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) You must use this material as applicable to do the actions
required by this AD, unless the AD specifies otherwise.
(i) European Union Aviation Safety Agency (EASA) AD 2022-0140,
dated July 7, 2022.
(ii) [Reserved]
(3) For EASA material identified in this AD, contact EASA,
Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; telephone +49 221
8999 000; email [email protected]; internet easa.europa.eu. You may
find the EASA material on the EASA website at ad.easa.europa.eu.
(4) You may view this material at the FAA, Office of the
Regional Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 6N-
321, Fort Worth, TX 76177. For information on the availability of
this material at the FAA, call (817) 222-5110.
(5) You may view this material at the National Archives and
Records Administration (NARA). For information on the availability
of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email [email protected].
Issued on September 10, 2024.
Victor Wicklund,
Deputy Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2024-20844 Filed 9-13-24; 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 2026-10-09T01:28:21.624946+00:00. Text extraction preserves the recorded source wording; it does not determine current requirements.
Open the captured official edition
- Source SHA-256
- cc0e2a5bb0211e94657995c8c0535009fbb726d074f6dae4e8878ed770c82edd
- Text SHA-256
- 5195040cc067a3f7f4948dcebd6beaa84f0acde59f76f1f176c6d4ec3e43790e
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.