# N951XV: 2017 Airbus A321-253N - Status: Valid registration - Airframe: [Airbus A321-253N](https://openairdocs.org/model/airbus-a321-253n) (registry code 3940045, 222 seats) - Engine: [CFM International LEAP-1A33](https://openairdocs.org/engine/cfm-international-leap-1a33) (registry code 13115) - Data sheets: [TCDS A28NM](https://openairdocs.org/tcds/A28NM) (Airbus SAS), [TCDS E00089EN](https://openairdocs.org/tcds/E00089EN) (CFM International S.A.) (OpenAirDocs) - Serial number: 7639 - Year built: 2017 - Type: Fixed wing multi engine - Engine type: Turbo-fan - Airworthiness: Standard, transport - Airworthiness date: May 24, 2017 - Certificate issued: January 10, 2024 - Expires: January 31, 2031 - Mode S code: AD3A7F - Registered owner: [American Airlines Inc](https://openairdocs.org/faa-owner/AMERICAN%20AIRLINES%20INC) - Location: [Fort Worth, TX](https://openairdocs.org/faa-place/TX/Fort%20Worth) - Owner type: Corporation - Owner's area on the map: 32.8240° N, 97.0491° W: Placed by OpenAirDocs at the center of ZIP code 76155, within about a mile (OpenAirDocs). The owner's mailing address, not where the aircraft is based - FAA registry: https://registry.faa.gov/AircraftInquiry/Search/NNumberResult?nNumberTxt=951XV - Page: https://openairdocs.org/aircraft/N951XV From the FAA registry file of October 24, 2026. ADs below are matched by the registry's airframe and engine model codes. They may apply; each AD's applicability can narrow it by serial number, part number or installed equipment. This is not a compliance determination. ## ADs that may apply (OpenAirDocs): 82 in force ### Matched by airframe (Airbus A321-253N) - [AD 2026-17-04](https://openairdocs.org/ad/2026-17-04): Landing Gear · Airbus A318-111, A318-112, A318-121 and 46 more. Effective Oct 1, 2026 - [AD 2026-15-13](https://openairdocs.org/ad/2026-15-13): Pneumatic · Airbus A319-151N, A319-153N, A319-171N and 19 more. Effective Sep 2, 2026 - [AD 2026-14-05](https://openairdocs.org/ad/2026-14-05): Communications · Airbus A319-151N, A319-153N, A319-171N and 19 more. Effective Aug 14, 2026 - [AD 2026-14-04](https://openairdocs.org/ad/2026-14-04): Fuselage · Airbus A319-111, A319-112, A319-113 and 56 more. Effective Aug 14, 2026 - [AD 2026-12-02](https://openairdocs.org/ad/2026-12-02): Fuselage · Airbus A318-111, A318-112, A318-121 and 46 more. Effective Jul 14, 2026 - [AD 2026-10-15](https://openairdocs.org/ad/2026-10-15): Fuselage · Airbus A318-111, A318-112, A318-122 and 35 more. Effective Jul 6, 2026 - [AD 2026-13-02](https://openairdocs.org/ad/2026-13-02): Navigation · Airbus Canada Limited Partnership 18, 49-46, 80-A and 555 more. Effective Jul 1, 2026 - [AD 2026-09-17](https://openairdocs.org/ad/2026-09-17): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 45 more. Effective Jun 18, 2026 - [AD 2026-09-16](https://openairdocs.org/ad/2026-09-16): Fuselage · Airbus A319-111, A319-112, A319-113 and 33 more. Effective Jun 18, 2026 - [AD 2026-11-04](https://openairdocs.org/ad/2026-11-04): Stabilizers · Airbus A319-111, A319-112, A319-113 and 40 more. Effective Jun 15, 2026 - [AD 2026-09-03](https://openairdocs.org/ad/2026-09-03): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 45 more. Effective Jun 12, 2026 - [AD 2026-03-10](https://openairdocs.org/ad/2026-03-10): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 45 more. Effective Apr 8, 2026 - [AD 2025-24-51](https://openairdocs.org/ad/2025-24-51): Flight controls · Airbus A319-111, A319-112, A319-113 and 37 more. Effective Jan 6, 2026 - [AD 2025-20-15](https://openairdocs.org/ad/2025-20-15): Fuselage · Airbus A318-111, A318-112, A318-121 and 43 more. Effective Jan 2, 2026 - [AD 2025-18-03](https://openairdocs.org/ad/2025-18-03): Oxygen · Airbus A318-111, A318-112, A318-121 and 70 more. Effective Oct 20, 2025 - [AD 2025-16-10](https://openairdocs.org/ad/2025-16-10): Flight controls · Airbus A318-111, A318-112, A318-121 and 44 more. Effective Sep 22, 2025 - [AD 2025-16-04](https://openairdocs.org/ad/2025-16-04): Equipment/furnishings · Airbus A318-111, A318-112, A318-121 and 46 more. Effective Sep 18, 2025 - [AD 2025-17-17](https://openairdocs.org/ad/2025-17-17): Landing Gear · Airbus A318-111, A318-112, A318-121 and 46 more. Effective Sep 17, 2025 - [AD 2025-13-10](https://openairdocs.org/ad/2025-13-10): Wings · Airbus A319-111, A319-112, A319-113 and 36 more. Effective Aug 14, 2025 - [AD 2025-10-07](https://openairdocs.org/ad/2025-10-07): Fuselage · Airbus A318-111, A318-112, A318-121 and 43 more. Effective Jun 26, 2025 - [AD 2025-10-05](https://openairdocs.org/ad/2025-10-05): Landing gear · Airbus A321-111, A321-112, A321-131 and 15 more. Effective Jun 26, 2025 - [AD 2025-02-04](https://openairdocs.org/ad/2025-02-04): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 43 more. Effective Mar 17, 2025 - [AD 2024-26-05](https://openairdocs.org/ad/2024-26-05): Oxygen · Airbus A300 B4-601, A300 B4-603, A300 B4-620 and 87 more. Effective Mar 11, 2025 - [AD 2024-25-12](https://openairdocs.org/ad/2024-25-12): Landing gear · Airbus A319-111, A319-112, A319-113 and 35 more. Effective Mar 7, 2025 - [AD 2025-03-08](https://openairdocs.org/ad/2025-03-08): Flight Controls · Airbus A318-111, A318-112, A318-121 and 70 more. Effective Feb 26, 2025 - [AD 2024-26-04](https://openairdocs.org/ad/2024-26-04): Pneumatic · Airbus A318-111, A318-112, A318-121 and 44 more. Effective Feb 18, 2025 - [AD 2024-24-10](https://openairdocs.org/ad/2024-24-10): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 43 more. Effective Jan 13, 2025 - [AD 2024-24-09](https://openairdocs.org/ad/2024-24-09): Equipment/Furnishings · Airbus A318-111, A318-112, A318-121 and 43 more. Effective Jan 13, 2025 - [AD 2024-19-15](https://openairdocs.org/ad/2024-19-15): Oxygen · Safran Aerosystems Oxygen Cylinder, Valve Assembly, Oxygen Valve and 103 more. Effective Nov 26, 2024 - [AD 2024-11-01](https://openairdocs.org/ad/2024-11-01): Electrical Power · Airbus A300 B4-2C, A300 B4-103, A300 B4-203 and 94 more. Effective Jul 3, 2024 - [AD 2024-08-08](https://openairdocs.org/ad/2024-08-08): Electrical Power · Airbus A300 B4-2C, A300 B4-103, A300 B4-203 and 94 more. Effective Jun 6, 2024 - [AD 2024-06-07](https://openairdocs.org/ad/2024-06-07): Wings · Airbus A319-115, A320-214, A320-216 and 14 more. Effective May 22, 2024 - [AD 2023-25-05](https://openairdocs.org/ad/2023-25-05): Landing Gear, Electrical System Installation · Airbus A319-151N, A319-153N, A319-171N and 16 more. Effective Feb 7, 2024 - [AD 2023-20-12](https://openairdocs.org/ad/2023-20-12): Equipment/Furnishings · Airbus A318-111, A318-112, A318-121 and 38 more. Effective Nov 21, 2023 - [AD 2023-10-07](https://openairdocs.org/ad/2023-10-07): Fuel · Airbus A319-151N, A319-153N, A319-171N and 16 more. Effective Nov 9, 2023 - [AD 2023-13-03](https://openairdocs.org/ad/2023-13-03): Doors · Airbus A318-111, A318-112, A318-121 and 43 more. Effective Sep 5, 2023 - [AD 2023-13-01](https://openairdocs.org/ad/2023-13-01): Fuel · Airbus A318-111, A318-112, A318-121 and 43 more. Effective Jul 12, 2023 - [AD 2023-10-02](https://openairdocs.org/ad/2023-10-02): Indicating/Recording System, Navigation · Boeing 18, 23, 35 and 1,060 more. Effective May 26, 2023 - [AD 2022-24-14](https://openairdocs.org/ad/2022-24-14): Auto Flight · Airbus A319-111, A319-112, A319-113 and 20 more. Effective Jan 18, 2023 - [AD 2020-25-03 R1](https://openairdocs.org/ad/2020-25-03-R1): Equipment/furnishings · Airbus A318-111, A318-112, A318-121 and 42 more. Effective Jan 12, 2023 - [AD 2022-24-03](https://openairdocs.org/ad/2022-24-03): Powerplant · Airbus A321-251N, A321-251NX, A321-252N and 3 more. Effective Jan 9, 2023 - [AD 2022-22-11](https://openairdocs.org/ad/2022-22-11): Flight Control System, Navigation · Airbus A319-151N, A319-153N, A319-171N and 16 more. Effective Dec 30, 2022 - [AD 2022-19-10](https://openairdocs.org/ad/2022-19-10): Equipment/furnishings · Airbus A321-251N, A321-251NX, A321-252NX and 3 more. Effective Oct 19, 2022 - [AD 2022-18-05](https://openairdocs.org/ad/2022-18-05): Equipment/furnishings · Airbus A318-111, A318-112, A318-121 and 43 more. Effective Oct 13, 2022 - [AD 2022-20-06](https://openairdocs.org/ad/2022-20-06): Ice and rain protection, Pneumatic · Airbus A320-251N, A320-253N, A320-271N and 4 more. Effective Oct 7, 2022 - [AD 2022-15-08](https://openairdocs.org/ad/2022-15-08): Information systems · Airbus A318-111, A318-112, A319-111 and 49 more. Effective Aug 12, 2022 - [AD 2022-04-08](https://openairdocs.org/ad/2022-04-08): Fire protection, Doors · Airbus A318-111, A318-112, A318-121 and 43 more. Effective Apr 11, 2022 - [AD 2021-22-07](https://openairdocs.org/ad/2021-22-07): Fire Bottle, Portable · Airbus A319-111, A319-112, A319-113 and 127 more. Effective Nov 18, 2021 - [AD 2021-18-04](https://openairdocs.org/ad/2021-18-04): Fire protection, Doors · Airbus A318-111, A318-112, A318-121 and 43 more. Effective Oct 20, 2021 - [AD 2021-11-06](https://openairdocs.org/ad/2021-11-06): Windows · Airbus A318-111, A318-112, A318-121 and 43 more. Effective Jun 4, 2021 ### Matched by engine (CFM International LEAP-1A33) - [AD 2026-14-06](https://openairdocs.org/ad/2026-14-06): Turbine Section · CFM International LEAP-1A23, LEAP-1A24, LEAP-1A24E1 and 10 more. Effective Jul 27, 2026 - [AD 2026-02-04](https://openairdocs.org/ad/2026-02-04): Turbine Engine Compressor Section · CFM International LEAP-1A23, LEAP-1A24, LEAP-1A24E1 and 10 more. Effective Feb 26, 2026 - [AD 2026-02-08](https://openairdocs.org/ad/2026-02-08): Engine Controls · CFM International LEAP-1A23, LEAP-1A24, LEAP-1A24E1 and 10 more. Effective Feb 25, 2026 - [AD 2025-21-03](https://openairdocs.org/ad/2025-21-03): Turbine section · CFM International LEAP-1A23, LEAP-1A24, LEAP-1A24E1 and 10 more. Effective Dec 29, 2025 - [AD 2025-12-03](https://openairdocs.org/ad/2025-12-03): Turbine Engine Compressor Section; Turbine Section · CFM International LEAP-1A23, LEAP-1A24, LEAP-1A24E1 and 10 more. Effective Jul 25, 2025 - [AD 2025-04-12](https://openairdocs.org/ad/2025-04-12): Turbine Section · CFM International LEAP-1A23, LEAP-1A24, LEAP-1A24E1 and 24 more. Effective Apr 8, 2025 - [AD 2025-01-03](https://openairdocs.org/ad/2025-01-03): Turbine Section · CFM International LEAP-1A23, LEAP-1A24, LEAP-1A24E1 and 13 more. Effective Mar 11, 2025 - [AD 2024-07-02](https://openairdocs.org/ad/2024-07-02): Turbine Section · CFM International LEAP-1A23, LEAP-1A24, LEAP-1A24E1 and 10 more. Effective Jun 10, 2024 - [AD 2024-07-06](https://openairdocs.org/ad/2024-07-06): Turbine Engine Compressor Section · CFM International LEAP-1A23, LEAP-1A24, LEAP-1A24E1 and 10 more. Effective Jun 3, 2024 - [AD 2022-17-12](https://openairdocs.org/ad/2022-17-12): Turbine Section · CFM International LEAP-1A23, LEAP-1A24, LEAP-1A24E1 and 10 more. Effective Oct 6, 2022 - [AD 2022-15-04](https://openairdocs.org/ad/2022-15-04): Turbine Section · CFM International LEAP-1A23, LEAP-1A24, LEAP-1A24E1 and 10 more. Effective Aug 4, 2022 - [AD 2022-14-02](https://openairdocs.org/ad/2022-14-02): Turbine Engine Compressor Section, Turbine Section · CFM International LEAP-1A23, LEAP-1A24, LEAP-1A24E1 and 10 more. Effective Jul 18, 2022 - [AD 2022-09-09](https://openairdocs.org/ad/2022-09-09): Turbine Engine Compressor Section, Turbine Section · CFM International LEAP-1A23, LEAP-1A24, LEAP-1A24E1 and 10 more. Effective Jun 21, 2022 - [AD 2021-11-21](https://openairdocs.org/ad/2021-11-21): Turbine Section · CFM International LEAP-1A23, LEAP-1A24, LEAP-1A24E1 and 10 more. Effective Jul 15, 2021 - [AD 2020-25-13](https://openairdocs.org/ad/2020-25-13): Turbine Section · CFM International LEAP-1A23, LEAP-1A24, LEAP-1A24E1 and 10 more. Effective Jan 25, 2021 - [AD 2017-24-06](https://openairdocs.org/ad/2017-24-06): Turbine Section · CFM International LEAP-1A23, LEAP-1A24, LEAP-1A24E1 and 7 more. Effective Dec 15, 2017 ### Historical (superseded or no longer in force) - [AD 2025-17-07](https://openairdocs.org/ad/2025-17-07) (historical): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 44 more. Effective Oct 1, 2025 - [AD 2025-16-12](https://openairdocs.org/ad/2025-16-12) (historical): Pneumatic · Airbus A319-151N, A319-153N, A319-171N and 19 more. Effective Aug 29, 2025 - [AD 2025-10-12](https://openairdocs.org/ad/2025-10-12) (historical): Fuselage · Airbus A319-111, A319-112, A319-113 and 55 more. Effective Jul 2, 2025 - [AD 2025-11-02](https://openairdocs.org/ad/2025-11-02) (historical): Communications · Airbus A319-151N, A319-153N, A319-171N and 18 more. Effective Jun 11, 2025 - [AD 2025-03-07](https://openairdocs.org/ad/2025-03-07) (historical): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 43 more. Effective Mar 21, 2025 - [AD 2025-03-06](https://openairdocs.org/ad/2025-03-06) (historical): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 43 more. Effective Mar 21, 2025 - [AD 2024-25-06](https://openairdocs.org/ad/2024-25-06) (historical): Landing Gear · Airbus A318-111, A318-112, A318-121 and 44 more. Effective Dec 30, 2024 - [AD 2024-19-13](https://openairdocs.org/ad/2024-19-13) (historical): Time Limits/Maintenance Checks · Airbus A320-211, A320-212, A320-214 and 43 more. Effective Nov 26, 2024 - [AD 2024-04-07](https://openairdocs.org/ad/2024-04-07) (historical): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 43 more. Effective Apr 22, 2024 - [AD 2024-04-03](https://openairdocs.org/ad/2024-04-03) (historical): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 43 more. Effective Apr 19, 2024 - [AD 2023-25-09](https://openairdocs.org/ad/2023-25-09) (historical): Oxygen · Airbus A318-111, A318-112, A318-121 and 69 more. Effective Feb 7, 2024 - [AD 2023-13-11](https://openairdocs.org/ad/2023-13-11) (historical): Oxygen · AVOX Systems Oxygen valve assemblies (body and gage assemblies), Oxygen cylinder and valve assemblies, A300 B2-1A and 102 more. Effective Sep 5, 2023 - [AD 2023-13-10](https://openairdocs.org/ad/2023-13-10) (historical): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 43 more. Effective Sep 5, 2023 - [AD 2023-09-01](https://openairdocs.org/ad/2023-09-01) (historical): Pneumatic · Airbus A318-111, A318-112, A318-121 and 43 more. Effective Jun 26, 2023 - [AD 2023-05-02](https://openairdocs.org/ad/2023-05-02) (historical): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 43 more. Effective Apr 18, 2023 - [AD 2023-04-06](https://openairdocs.org/ad/2023-04-06) (historical): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 43 more. Effective Apr 10, 2023 - [AD 2022-24-05](https://openairdocs.org/ad/2022-24-05) (historical): Equipment/Furnishings · Airbus A318-111, A318-112, A318-121 and 43 more. Effective Jan 9, 2023 - [AD 2022-22-10](https://openairdocs.org/ad/2022-22-10) (historical): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 43 more. Effective Dec 30, 2022 - [AD 2022-18-09](https://openairdocs.org/ad/2022-18-09) (historical): Equipment/Furnishings · Airbus A319-111, A319-112, A319-113 and 24 more. Effective Oct 20, 2022 - [AD 2022-09-16](https://openairdocs.org/ad/2022-09-16) (historical): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 42 more. Effective Jun 30, 2022 - [AD 2022-07-08](https://openairdocs.org/ad/2022-07-08) (historical): Time Limits/Maintenance Checks, Flight Controls · Airbus A318-111, A318-112, A318-121 and 43 more. Effective May 19, 2022 - [AD 2022-07-15](https://openairdocs.org/ad/2022-07-15) (historical): Landing gear · Airbus A318-111, A318-112, A318-121 and 43 more. Effective May 2, 2022 - [AD 2022-04-09](https://openairdocs.org/ad/2022-04-09) (historical): Oxygen System · Airbus A300 B2-1A, A300 B2-1C, A300 B2K-3C and 94 more. Effective Apr 4, 2022 - [AD 2022-04-03](https://openairdocs.org/ad/2022-04-03) (historical): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 42 more. Effective Mar 30, 2022 - [AD 2021-20-08](https://openairdocs.org/ad/2021-20-08) (historical): Electrical Power · Airbus A318-111, A318-112, A318-121 and 72 more. Effective Nov 18, 2021 - [AD 2021-16-01](https://openairdocs.org/ad/2021-16-01) (historical): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 42 more. Effective Sep 28, 2021 - [AD 2021-14-08](https://openairdocs.org/ad/2021-14-08) (historical): Navigation · Airbus A319-151N, A319-153N, A319-171N and 16 more. Effective Jul 1, 2021 - [AD 2020-25-03](https://openairdocs.org/ad/2020-25-03) (historical): Equipment/furnishings · Airbus A318-111, A318-112, A318-121 and 42 more. Effective Dec 28, 2020 - [AD 2020-22-16](https://openairdocs.org/ad/2020-22-16) (historical): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 42 more. Effective Dec 10, 2020 - [AD 2020-21-11](https://openairdocs.org/ad/2020-21-11) (historical): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 42 more. Effective Nov 20, 2020 - [AD 2020-21-10](https://openairdocs.org/ad/2020-21-10) (historical): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 42 more. Effective Nov 19, 2020 - [AD 2020-20-05](https://openairdocs.org/ad/2020-20-05) (historical): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 42 more. Effective Nov 19, 2020 - [AD 2020-16-01](https://openairdocs.org/ad/2020-16-01) (historical): Fire protection · Airbus A318-111, A318-112, A318-121 and 43 more. Effective Aug 19, 2020 - [AD 2020-12-11](https://openairdocs.org/ad/2020-12-11) (historical): Auto Flight · Airbus A319-111, A319-112, A319-113 and 20 more. Effective Jul 24, 2020 - [AD 2020-05-16](https://openairdocs.org/ad/2020-05-16) (historical): Wings · Airbus A319-115, A320-214, A320-216 and 11 more. Effective Apr 24, 2020 - [AD 2020-06-18](https://openairdocs.org/ad/2020-06-18) (historical): Flight controls · Airbus A318-111, A318-112, A318-121 and 43 more. Effective Apr 2, 2020 - [AD 2019-26-11](https://openairdocs.org/ad/2019-26-11) (historical): Equipment/ furnishings · Airbus A318-112, A319-115, A319-132 and 11 more. Effective Mar 12, 2020 - [AD 2020-01-17](https://openairdocs.org/ad/2020-01-17) (historical): Equipment/ furnishings · Airbus A318-111, A318-112, A318-121 and 43 more. Effective Feb 14, 2020 - [AD 2019-23-01](https://openairdocs.org/ad/2019-23-01) (historical): Time Limits/ Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 37 more. Effective Jan 9, 2020 - [AD 2019-20-03](https://openairdocs.org/ad/2019-20-03) (historical): Information systems · Airbus A340-312, A340-313, A318-111 and 48 more. Effective Nov 19, 2019 - [AD 2019-19-15](https://openairdocs.org/ad/2019-19-15) (historical): Time Limits/ Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 36 more. Effective Nov 14, 2019 - [AD 2019-14-04](https://openairdocs.org/ad/2019-14-04) (historical): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 37 more. Effective Aug 29, 2019 - [AD 2019-05-09](https://openairdocs.org/ad/2019-05-09) (historical): Electric and electronic common installation · Airbus A320-251N, A320-271N and A321-253N. Effective Apr 4, 2019 - [AD 2019-03-17](https://openairdocs.org/ad/2019-03-17) (historical): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 36 more. Effective Apr 3, 2019 - [AD 2018-25-02](https://openairdocs.org/ad/2018-25-02) (historical): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 30 more. Effective Jan 10, 2019 - [AD 2018-17-19](https://openairdocs.org/ad/2018-17-19) (historical): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 29 more. Effective Oct 5, 2018 - [AD 2018-16-04](https://openairdocs.org/ad/2018-16-04) (historical): Time Limits/Maintenance Checks · Airbus A318-111, A318-112, A318-121 and 29 more. Effective Sep 14, 2018 - [AD 2023-09-06](https://openairdocs.org/ad/2023-09-06) (historical): Turbine Section · CFM International LEAP-1A23, LEAP-1A24, LEAP-1A24E1 and 10 more. Effective Jun 23, 2023 - [AD 2018-19-16](https://openairdocs.org/ad/2018-19-16) (historical): Engine Controls · CFM International LEAP-1A23, LEAP-1A24, LEAP-1A24E1 and 10 more. Effective Oct 25, 2018 All 131: https://openairdocs.org/aircraft/N951XV/ads.md ## Information bulletins (advisory) (1 in force) - [SAIB NE-19-03](https://openairdocs.org/saib/NE-19-03): Escape Slide Maintenance Tasks and Intervals - JASC 2565. Issued Feb 19, 2019 ## NTSB investigations None matched to N951XV. ## FAA accident and incident reports None matched to N951XV. ## Service difficulty reports (34) As reported by operators and repair stations. Matched to this aircraft by N-number and event date, checked against the reported serial number, make and model. - [SDR AALA202610192443](https://openairdocs.org/sdr/AALA202610192443), Oct 18, 2026: SMOKE DETECTOR. FALSE INDICATION. AIRCRAFT WAS NOT GROUNDED: SMOKE LAVATORY WARNING ECAM ALERTED FOR 5 SECOND THEN CLEARED - F/A INVESTIGATED LAVS AND FOUND NOTHING ABNORMAL - MAINTENANCE CHECKE - [SDR AALA202610162184](https://openairdocs.org/sdr/AALA202610162184), Oct 15, 2026: BOTTLE. LOW PRESSURE. AIRCRAFT WAS NOT GROUNDED: L1 DOOR ASSIST BOTTLE LOW. MAINTENANCE SERVICED L1 DOOR ASSIST BOTTLE PER JOBCARD 26L00005005. - [SDR AALA202609026642](https://openairdocs.org/sdr/AALA202609026642), Aug 31, 2026: BATTERY. NO TEST. AIRCRAFT WAS NOT GROUNDED: EMERGENCY FLASHLIGHT LOCATED UNDERNEATH THE AFT LEFT GALLEY FLIGHT ATTENDANT SEAT IS INOPERATIVE - MAINTENANCE REPLACED THE FLASHLGHT - [SDR AALA202609027560](https://openairdocs.org/sdr/AALA202609027560), Aug 31, 2026: FLASHLIGHT. NO TEST. AIRCRAFT WAS NOT GROUNDED: EMERGENCY FLASHLIGHT LOCATED UNDERNEATH THE AFT LEFT GALLEY FLIGHT ATTENDANT SEAT IS INOPERATIVE - MAINTENANCE REPLACED THE FLASHLGHT - [SDR AALA202608101074](https://openairdocs.org/sdr/AALA202608101074), Aug 9, 2026: VALVE. DEFECTIVE. AIRCRAFT WAS GROUNDED: FLIGHT CREW REPORTED THAT AT FL 360 THERE WAS A FUEL IMBALANCE OF 3000 THOUSAND POUNDS DIFFERENCE FROM TANK 1 TO TANK 2 - MAINTENANCE REP - [SDR AALA202604270207](https://openairdocs.org/sdr/AALA202604270207), Apr 26, 2026: HANDLE. LOOSE. AIRCRAFT WAS GROUNDED: LEFT-HAND FORWARD EMERGENCY EXIT DOOR ARM/DISARM HANDLE LOOSE AND NOT SECURE TO ARM. MAINTENANCE TIGHTENED THE HANDLE AND ACCOMPLISHED A - [SDR AALA202602027554](https://openairdocs.org/sdr/AALA202602027554), Jan 30, 2026: WIRE. MISINSTALLED. AIRCRAFT WAS NOT GROUNDED: EMERGENCY CEILING LIGHT AT SEAT ROW 11 IS INOPERATIVE. MAINTENANCE REINSTALLED EMERGENCY OVERHEAD WIRING LIGHTING AND ACCOMPLISHED A - [SDR AALA202511065305](https://openairdocs.org/sdr/AALA202511065305), Nov 6, 2025: BOTTLE. LOW PRESSURE. AIRCRAFT WAS NOT GROUNDED: L1 DOOR DAMPER AND EMERGENCY OPERATION CYLINDER PRESSURE LOW. SERVICED DOOR DAMPER AND EMERGENCY OPERATION CYLINDER PER AMM 52-10-00. - [SDR AALA202510157289](https://openairdocs.org/sdr/AALA202510157289), Oct 12, 2025: BOTTLE. LOW PRESSURE. AIRCRAFT WAS NOT GROUNDED: L3 DOOR DAMPER AND EMERGENCY OPERATION CYLINDER PRESSURE LOW. SERVICED DOOR DAMPER AND EMERGENCY OPERATION CYLINDER PER AMM 52-10-00. - [SDR AALA202510151018](https://openairdocs.org/sdr/AALA202510151018), Oct 12, 2025: BOTTLE. LOW PRESSURE. AIRCRAFT WAS NOT GROUNDED: L1 DOOR DAMPER AND EMERGENCY OPERATION CYLINDER PRESSURE LOW. SERVICED DOOR DAMPER AND EMERGENCY OPERATION CYLINDER PER AMM 52-10-00. - [SDR AALA202509020200](https://openairdocs.org/sdr/AALA202509020200), Sep 1, 2025: BOTTLE. LOW PRESSURE. AIRCRAFT WAS NOT GROUNDED: L1 DOOR DAMPER AND EMERGENCY OPERATION CYLINDER PRESSURE LOW. SERVICED DOOR DAMPER AND EMERGENCY OPERATION CYLINDER PER AMM 52-10-00. - [SDR AALA202506302673](https://openairdocs.org/sdr/AALA202506302673), Jun 28, 2025: LANYARD. OUT OF POSITION. AIRCRAFT WAS GROUNDED: 4R DOOR HARD TO ARM AND DISARM. MAINTENANCE RE-ADJUSTED GRIT BAR (AALA202506292736) POSITION AND LANYARD STRAPS (AALA202506302673) PER AM - [SDR AALA202506302736](https://openairdocs.org/sdr/AALA202506302736), Jun 28, 2025: GIRT BAR. OUT OF POSITION. AIRCRAFT WAS GROUNDED: 4R DOOR HARD TO ARM AND DISARM. MAINTENANCE RE-ADJUSTED GRIT BAR (AALA202506292736) POSITION AND LANYARD STRAPS (AALA202506302673) PER AM - [SDR AALA202506240131](https://openairdocs.org/sdr/AALA202506240131), Jun 22, 2025: BOTTLE. LOW PRESSURE. AIRCRAFT WAS NOT GROUNDED: L1 DOOR DAMPER AND EMERGENCY OPERATION CYLINDER PRESSURE LOW. SERVICED DOOR DAMPER AND EMERGENCY OPERATION CYLINDER PER AMM 52-10-00. - [SDR AALA202506239092](https://openairdocs.org/sdr/AALA202506239092), Jun 20, 2025: SMOKE DETECTOR. FALSE ACTIVATION. AIRCRAFT WAS NOT GROUNDED: SMOKE DETECTOR IN LAVATORY WENT OFF AT CRUISE ALTITUDE FL250. FLIGHT ATTENDANTS CHECKED ALL LAVATORIES AND NOTHING NOTED. MAINTENANCE - [SDR AALA202506056022](https://openairdocs.org/sdr/AALA202506056022), Jun 4, 2025: BATTERY. NO TEST. AIRCRAFT WAS NOT GROUNDED: FLIGHT ATTENDANTS FLASHLIGHT AT 2L SEAL IS BROKEN AND THE GREEN INDICATOR LIGHT IS NOT ON. MAINTENANCE REPLACED THE FLASHLIGHT BATTER - [SDR AALA202505066733](https://openairdocs.org/sdr/AALA202505066733), May 5, 2025: BATTERY. NO TEST. AIRCRAFT IN BASE MAINTENANCE: FAULT MESSAGE FOR EMERGENCY POWER SUPPLY UNIT 10WL DISPLAYED DURING SYSTEM TEST. REPLACED PASSENGER / CREW DOOR 831 SLIDE RAFT PER - [SDR AALA202505060987](https://openairdocs.org/sdr/AALA202505060987), May 5, 2025: SLIDE RAFT. NO TEST. AIRCRAFT IN BASE MAINTENANCE: FAULT MESSAGE FOR EMERGENCY POWER SUPPLY UNIT 10WL DISPLAYED DURING SYSTEM TEST. REPLACED PASSENGER / CREW DOOR 831 SLIDE RAFT PER - [SDR AALA202503264093](https://openairdocs.org/sdr/AALA202503264093), Mar 24, 2025: BOTTLE. LOW PRESSURE. AIRCRAFT WAS NOT GROUNDED: R1 DOOR DAMPER AND EMERGENCY OPERATION CYLINDER PRESSURE LOW. SERVICED DOOR DAMPER AND EMERGENCY OPERATION CYLINDER PER AMM 52-10-00. - [SDR AALA202412035336](https://openairdocs.org/sdr/AALA202412035336), Dec 1, 2024: BOTTLE. LOW PRESSURE. AIRCRAFT WAS NOT GROUNDED: L1 DOOR EMERGENCY CYLINDER ACCUMULATOR LOW PSI (1100 PSI AT 62F). SERVICED L1 DOOR EMERGENCY CYLINDER ACCUMULATOR PER AMM 52-10-00. - [SDR AALA202410182094](https://openairdocs.org/sdr/AALA202410182094), Oct 17, 2024: BOTTLE. LOW PRESSURE. AIRCRAFT WAS GROUNDED: L1 DOOR DAMPER AND EMERGENCY OPERATION CYL.INDER PRESSURE LOW. SERVICED DAMPER AND EMERGENCY OPERATION CYL.INDER PER AMM 52-10-00. - [SDR AALA202410185005](https://openairdocs.org/sdr/AALA202410185005), Oct 17, 2024: BOTTLE. LOW PRESSURE. AIRCRAFT WAS GROUNDED: R2 DOOR DAMPER AND EMERGENCY OPERATION CYL.INDER PRESSURE LOW. SERVICED DAMPER AND EMERGENCY OPERATION CYL.INDER PER AMM 52-22-00. - [SDR AALA202410185426](https://openairdocs.org/sdr/AALA202410185426), Oct 17, 2024: BOTTLE. LOW PRESSURE. AIRCRAFT WAS GROUNDED: R3 DOOR DAMPER AND EMERGENCY OPERATION CYL.INDER PRESSURE LOW. SERVICED DAMPER AND EMERGENCY OPERATION CYL.INDER PER AMM 52-22-00. - [SDR AALA202410182197](https://openairdocs.org/sdr/AALA202410182197), Oct 17, 2024: BOTTLE. LOW PRESSURE. AIRCRAFT WAS GROUNDED: L3 DOOR DAMPER AND EMERGENCY OPERATION CYL.INDER PRESSURE LOW. SERVICED DAMPER AND EMERGENCY OPERATION CYL.INDER PER AMM 52-22-00. - [SDR AALA202410087883](https://openairdocs.org/sdr/AALA202410087883), Oct 7, 2024: ACCUMULATOR. LOW PRESSURE. AIRCRAFT WAS GROUNDED: RIGHT AFT CABIN DOOR ACCUMULATOR LOW. SERVICED DOOR ACCUMULATOR PER AMM 52-13-00. - [SDR AALA202409205134](https://openairdocs.org/sdr/AALA202409205134), Sep 19, 2024: CIRCUIT BREAKER. TRIPPED. AIRCRAFT WAS GROUNDED: CABIN EMERGENCY LIGHTS CIRCUIT BREAKER H7 TRIPPED DURING BOARDING. REMOVED AND REPLACED EMERGENCY LIGHT SWITCH 4WL. - [SDR AALA202409034924](https://openairdocs.org/sdr/AALA202409034924), Sep 2, 2024: FLASHLIGHT. INOPERATIVE. AIRCRAFT WAS NOT GROUNDED: BATTERY FLASHLIGHT INOPERATIVE AT OUTBOARD FLIGHT ATTENDANT SEAT L1 DOOR. REPLACED BATTERY FLASHLIGHT PER AMM 25-65-99. - [SDR AALA202408264979](https://openairdocs.org/sdr/AALA202408264979), Aug 24, 2024: DAMPER. LOW PRESSURE. AIRCRAFT WAS NOT GROUNDED: R1 DOOR BOTTLE LOW. SERVICED DOOR BOTTLE IAW MM 52-22-00 LEAK CHECK GOOD. - [SDR AALA202407299287](https://openairdocs.org/sdr/AALA202407299287), Jul 28, 2024: BATTERY. INOPERATIVE. AIRCRAFT WAS NOT GROUNDED: BATTERY/EMERGENCY POWER SUPPLY UNIT (15WL) EXTERNAL LEFT CLASS 1 MAINTENANCE MESSAGE AFTER SYSTEM TEST. REMOVED AND REPLACED 15WL BAT - [SDR AALA202407296264](https://openairdocs.org/sdr/AALA202407296264), Jul 28, 2024: BATTERY. INOPERATIVE. AIRCRAFT WAS NOT GROUNDED: BATTERY/EMERGENCY POWER SUPPLY UNIT (11WL) EXTERNAL LEFT CLASS 1 MAINTENANCE MESSAGE AFTER SYSTEM TEST. REMOVED AND REPLACED 11WL BAT - [SDR AALA202407116744](https://openairdocs.org/sdr/AALA202407116744), Jul 9, 2024: TOILET. ODOR. AIRCRAFT WAS GROUNDED: STRONG AMMONIA SMELL AT AFT GALLEY. SMELL WAS DETERMINED TO BE URINE. JOB CARD 26L00021001 WAS ACCOMPLISHED. LEFT AFT TOILET WAS REMOVED - [SDR AALA202406211531](https://openairdocs.org/sdr/AALA202406211531), Jun 21, 2024: BOTTLE. LOW PRESSURE. AIRCRAFT WAS GROUNDED: L1 DOOR DAMPER AND EMERGENCY OPERATION CYLINDER NEEDS TO BE SERVICED. MAINTENANCE SERVICED THE L1 DOOR DAMPER AND EMERGENCY OPERATION CYL - [SDR AALA202405152036](https://openairdocs.org/sdr/AALA202405152036), May 14, 2024: HANDLE. STUCK. AIRCRAFT WAS IN BASE MAINTENANCE: R3 EMERGENCY EXIT DOOR INTERNAL HANDLE IS HARD TO OPEN (059-09). REMOVED AND REPLACED ARM LEVERS IN SECTION TRANSVERSE AT R3 E - [SDR AALA202405156806](https://openairdocs.org/sdr/AALA202405156806), May 14, 2024: HANDLE. STUCK. AIRCRAFT WAS IN BASE MAINTENANCE: R3 EMERGENCY EXIT DOOR EXTERNAL HANDLE IS HARD TO OPEN (059-27). REMOVED AND REPLACED ARM LEVERS IN SECTION TRANSVERSE AT R3 E ## STCs that may be installed (OpenAirDocs) (107, first 50) Approved for this aircraft's airframe or engine model, in force first, then newest. The registry doesn't record which STCs an aircraft has; its records do. ### Approved for the airframe (Airbus A321-253N) - [STC ST12434AC](https://openairdocs.org/stc/ST12434AC): Replacement of the wing fuel tank access panel gasket. Aviation Devices & Electronic Components, LLC - [STC ST00885LA](https://openairdocs.org/stc/ST00885LA): Installation of fire extinguisher cartridges as replacements for Pacific Scientific fire extinguisher cartridges in fire extinguisher bottles. AMETEK AMERON, LLC d/b/a MASS Systems - [STC ST02528LA](https://openairdocs.org/stc/ST02528LA): Installation of the Thales Avionics, Inc. Data Transfer Device (DTD) or Solid State Drive (SSD) into the existing Cabin Media Loader (CML). Thales Avionics Inc - [STC ST04474NY](https://openairdocs.org/stc/ST04474NY): Activation of Wireless Local Area Network (WLAN) system. Jet Aviation AG - [STC ST04254NY](https://openairdocs.org/stc/ST04254NY): Installation of Viasat Satcom Software. ALOFT AeroArchitects - [STC ST03416NY](https://openairdocs.org/stc/ST03416NY): Installation of Intelsat Connectivity Antenna (with demod option). Delta Engineering Corporation - [STC ST02913NY](https://openairdocs.org/stc/ST02913NY): Installation of a Panasonic Avionics Corporation Global Communications Suite (GCS) and/or In-Flight Entertainment System. Delta Engineering Corporation - [STC ST01700AT-D](https://openairdocs.org/stc/ST01700AT-D): Installation of Airshow 420 System. AIRCRAFT RECONFIG TECHNOLOGIES, LLC. Lists A321 Series - [STC ST03741NY](https://openairdocs.org/stc/ST03741NY): Viasat KA SATCOM Antenna System Installation, approve configurations. ALOFT AeroArchitects - [STC ST12326SE](https://openairdocs.org/stc/ST12326SE): SpaceX Starlink Aviation System Installation and Activation. Space Exploration Technologies Corp./Starlink Aviation - [STC ST00142NY](https://openairdocs.org/stc/ST00142NY): Cargo floorboard installation. American Airlines, Inc., Maintenance and Engineering (M&E) Division - [STC ST02890NY](https://openairdocs.org/stc/ST02890NY): Installation of a Panasonic Avionics Corporation Global Communications Suite Antenna. Delta Engineering Corporation - [STC ST04759NY](https://openairdocs.org/stc/ST04759NY): Installation of a single cockpit USB charger. Eirtech Aviation Services Inc - [STC ST02356LA](https://openairdocs.org/stc/ST02356LA): Installation of Inflight Warning Systems Fan Vibration Monitor Unit. Astronics Advanced Electronic Systems (AES) - [STC ST02699LA](https://openairdocs.org/stc/ST02699LA): Installation of Vogt Aero Nickel Cadmium Battery P/N 2758-LMVA or 2758-RMVA. Vogt Aero LLC - [STC ST12229IB](https://openairdocs.org/stc/ST12229IB): Installation of Thinkom antenna on the top rear fuselage. EAD Aerospace Airworthiness T/A Eclipse Technics - [STC ST04288CH](https://openairdocs.org/stc/ST04288CH): Installation of an Automatic Dependent Surveillance Broadcast Out (ADS-B Out) Transponder System with Honeywell Integrated Multi-Mode Receiver (IMMR), Model Number IMMR 20.1 installed with TSO-C190 compliant GPS antenna. Amphenol Cable and Interconnect Technologies Inc - [STC ST04292CH](https://openairdocs.org/stc/ST04292CH): Installation of JADE SATCOM Antenna System Provisions. Amphenol Cable and Interconnect Technologies Inc - [STC ST00030IB](https://openairdocs.org/stc/ST00030IB): Installation of Test Tech ELT. APTOZ EHF - [STC ST01928LA](https://openairdocs.org/stc/ST01928LA): Installation of Forward LH/RH Windscreen, Mid LH/RH Class Divider, Aft LH Windscreen, Upper Attach Provision and Interior Installation. Safran Cabin Inc - [STC ST02735LA](https://openairdocs.org/stc/ST02735LA): Installation of modular lower deck Cargo Loading System (CLS). Telair International - [STC ST03417NY](https://openairdocs.org/stc/ST03417NY): Installation with demod option of Intelsat Cabin Connectivity System. Delta Engineering Corporation - [STC ST04089NY](https://openairdocs.org/stc/ST04089NY): Installation of Cabin Seating. Delta Engineering Corporation - [STC ST04798NY](https://openairdocs.org/stc/ST04798NY): AAR Engineering Services Seat Re-pitch. Delta Engineering Corporation - [STC ST02472AT](https://openairdocs.org/stc/ST02472AT): Installation of a mini Quick Access Recorder (QAR) model MKI, MKII, or MKIII. Aircraft Systems and Manufacturing Inc - [STC ST11892IB](https://openairdocs.org/stc/ST11892IB): Installation of monuments and emergency equipmen. Airbus SAS - [STC ST02612CH](https://openairdocs.org/stc/ST02612CH): Installation of AD Aerospace Cockpit Door Monitoring System. Amphenol Cable and Interconnect Technologies, Inc - [STC ST02626CH](https://openairdocs.org/stc/ST02626CH): Installation of ECS EZMount® mechanical mounting assemblies on lower frames of cockpit sliding windows. Amphenol Cable and Interconnect Technologies Inc - [STC ST11094DS](https://openairdocs.org/stc/ST11094DS): Installation of hanging soft dividers and sidewall mounted literature pockets. American Airlines, Inc., M&E Engineering Division - [STC ST04328CH](https://openairdocs.org/stc/ST04328CH): Installation and activation of the RAVE Wireless Broadband System. Amphenol Cable and Interconnect Technologies Inc - [STC ST04334CH](https://openairdocs.org/stc/ST04334CH): Installation and activation of an ARINC 791 SATCOM System. Amphenol Cable and Interconnect Technologies Inc - [STC ST04287CH](https://openairdocs.org/stc/ST04287CH): The Certification for Transmitting Portable Electronic Device (TPED). Amphenol Cable and Interconnect Technologies Inc - [STC ST11872IB](https://openairdocs.org/stc/ST11872IB): Installation of Iridium Antenna. Aerotec Concept - [STC ST04010NY](https://openairdocs.org/stc/ST04010NY): Installation of Reticulated Polyurethane Foam (RPF) For Center Fuel Tank Ignition Mitigation. AerSale Inc - [STC ST00079IB](https://openairdocs.org/stc/ST00079IB): Integration of Halon-free Portable Fire Extinguisher HAFEX. UMLAUT ENGINEERING GMBH - [STC ST00215IB](https://openairdocs.org/stc/ST00215IB): Installation of saf-Tglo ECO Photoluminescent Aisle Path Marking Systems. STG AEROSPACE GERMANY GmbH - [STC ST01936WI](https://openairdocs.org/stc/ST01936WI): Installation of LED lights. AeroLED's Holdings LLC - [STC ST02716SE](https://openairdocs.org/stc/ST02716SE): Conversion of an Airbus A321-200 passenger configuration airplane to a freighter configuration. 321 Precision Conversions LLC - [STC ST04071NY](https://openairdocs.org/stc/ST04071NY): Installation of VisionSafe Emergency Vision Assurance System (EVAS). VisionSafe LLC - [STC ST02626SE](https://openairdocs.org/stc/ST02626SE): Installation of seats, monuments and ISPS. Northwest Aerospace Technologies Inc - [STC ST02814CH](https://openairdocs.org/stc/ST02814CH): Installation of Rosemount Aerospace Electronic Flight Bag (EFB) System and Provisions. Rosemount Aerospace Inc - [STC ST09939AC](https://openairdocs.org/stc/ST09939AC): Installation of the Spacex Starlink Aviation Satcom System. Space Exploration Technologies Corp./Starlink Aviation - [STC ST04577AT](https://openairdocs.org/stc/ST04577AT): Installation of the ARTEX 4000 Emergency Locator Transmitter (ELT) System. Woven Electronics LLC - [STC ST04623CH](https://openairdocs.org/stc/ST04623CH): Installation of Flight Deck Power System. Rosemount Aerospace Inc - [STC ST00126IB](https://openairdocs.org/stc/ST00126IB): Replacement of Halon agent with alternate Halon-free Portable Fire Extinguisher agent. AMAC Aerospace Switzerland AG - [STC ST02267NY](https://openairdocs.org/stc/ST02267NY): Installation of Self Illuminating Floor Path Marking System. Lufthansa Technik AG - [STC ST04562NY](https://openairdocs.org/stc/ST04562NY): Installation of saf-Tglo® SuperSeal UltraLite-X (SSUL-X) Photoluminescent Floor Proximity Emergency Escape Path Marking Systems. STG AEROSPACE GERMANY GmbH - [STC ST00105IB](https://openairdocs.org/stc/ST00105IB): Introduction of Activation of Wireless Charging Systems for Portable Electronic Devices. AMAC AEROSPACE SWITZERLAND AG - [STC ST00898DE](https://openairdocs.org/stc/ST00898DE): Installation of Glide Lite In-Flight Entertainment System. Burrana Inc - [STC ST00098IB](https://openairdocs.org/stc/ST00098IB): Introduction of ADS-B Out. STC Twenty One Limited All 107: https://openairdocs.org/aircraft/N951XV/stcs.md ## Related - Other Airbus A321-253N aircraft: https://openairdocs.org/model/airbus-a321-253n/aircraft.md - The CFM International LEAP-1A33 engine: https://openairdocs.org/engine/cfm-international-leap-1a33.md --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.