# NTSB investigations: Landing

NTSB aviation accident and incident investigations since 1962: the probable cause, findings, aircraft, crew, weather and docket of each, linked to the FAA registry and the FAA’s own reports.

Page 93 of 1,075 · 53,702 cases

## Cases, newest first

- [NTSB GAA17CA128](https://openairdocs.org/ntsb/GAA17CA128.md): Cessna 210 · Charleston, WV · Accident · No injuries · Data collection · Final report · Jan 28, 2017 · N59196 · Substantial damage
  > The pilot’s improper landing flare in gusting wind conditions, which resulted in a hard landing and runway excursion.
- [NTSB GAA17CA127](https://openairdocs.org/ntsb/GAA17CA127.md): Vaughan Gerald R Side Winder TD · McCook, NE · Accident · No injuries · Data collection · Final report · Jan 28, 2017 · N60JV · Substantial damage
  > The pilot’s failure to maintain directional control during the landing roll in gusting wind conditions.
- [NTSB GAA17CA125](https://openairdocs.org/ntsb/GAA17CA125.md): Great Lakes 2T1A · Canon City, CO · Accident · No injuries · Data collection · Final report · Jan 28, 2017 · N16GL · Substantial damage
  > The pilot’s failure to maintain directional control during the landing roll. Contributing to the accident was the pilot’s unstabilized approach.
- [NTSB DCA17WA061](https://openairdocs.org/ntsb/DCA17WA061.md): Boeing 737 · Leticia, Colombia · Accident · No injuries · Foreign investigation · Jan 28, 2017 · HK-5197 · Substantial damage
  > The Civil Aviation Authority (CAA) of Colombia has notified the NTSB of an accident involving a Boeing 737 airplane that occurred on January 28, 2017. The NTSB has appointed a U.S. Accredited Representative to assist the government of Colombia's investigation…
- [NTSB ERA17LA096](https://openairdocs.org/ntsb/ERA17LA096.md): Beech 200 · West Palm Beach, FL · Accident · No injuries · Limited investigation · Final report · Jan 27, 2017 · N60RA · Substantial damage
  > The pilot's failure to ensure that the landing gear were down and locked before touchdown. Contributing to the accident was the pilot’s self-reported fatigue at the time of the accident.
- [NTSB GAA17CA129](https://openairdocs.org/ntsb/GAA17CA129.md): Cessna 182 · Midland, TX · Accident · No injuries · Data collection · Final report · Jan 26, 2017 · N38EE · Substantial damage
  > The student pilot's improper landing flare, which resulted in a bounced landing.
- [NTSB GAA17CA126](https://openairdocs.org/ntsb/GAA17CA126.md): Piper PA32R · Fort Mohave, AZ · Accident · No injuries · Data collection · Final report · Jan 26, 2017 · N6885F · Substantial damage
  > The pilot's failure to extend the landing gear for landing.
- [NTSB ERA17LA095](https://openairdocs.org/ntsb/ERA17LA095.md): Cessna 172 · Clearwater, FL · Accident · No injuries · Limited investigation · Final report · Jan 26, 2017 · N2382R · Substantial damage
  > The pilot's improper landing flare, which resulted in damage to the engine firewall.
- [NTSB GAA17CA123](https://openairdocs.org/ntsb/GAA17CA123.md): Piper PA 28R · Wichita, KS · Accident · No injuries · Data collection · Final report · Jan 24, 2017 · N4792T · Substantial damage
  > The pilot's failure to maintain directional control while landing in gusting crosswind conditions.
- [NTSB CEN17LA188](https://openairdocs.org/ntsb/CEN17LA188.md): Bell 407 · Fort Worth, TX · Accident · No injuries · Limited investigation · Final report · Jan 24, 2017 · N6040Y · Substantial damage
  > The flight instructor's failure to prevent the engine/rotor overspeed condition during the demonstration maneuver and the excessive descent rate during the emergency landing, which resulted in a hard landing. Contributing to the engine/rotor overspeed…
- [NTSB GAA17CA133](https://openairdocs.org/ntsb/GAA17CA133.md): Cessna 182 · Sebring, OH · Accident · No injuries · Data collection · Final report · Jan 22, 2017 · N3828D · Substantial damage
  > The pilot’s failure to maintain the proper glidepath during landing, which resulted in the airplane landing short of the runway, the nose landing gear separating, and the airplane nosing over during a second landing.
- [NTSB DCA17WA068](https://openairdocs.org/ntsb/DCA17WA068.md): Boeing 737 · Dhaka, India · Incident · No injuries · Foreign investigation · Jan 22, 2017 · VT-JTD · Minor damage
  > The Aircraft Accident Investigation Bureau (AAIB) of India has notified the NTSB of an accident involving a Boeing 737 airplane that occurred on January 22, 2017. The NTSB has appointed a U.S. Accredited Representative to assist the AAIB's investigation under…
- [NTSB DCA17WA066](https://openairdocs.org/ntsb/DCA17WA066.md): Avro 146 · Darlot, Australia · Incident · No injuries · Foreign investigation · Jan 20, 2017 · UNK · Minor damage
  > The Australian Transport Safety Bureau (ATSB) has notified the NTSB of an accident involving a AVRO RJ146 airplane equipped with Lycoming LF507 engines that occurred on January 20, 2017. The NTSB has appointed a U.S. Accredited Representative to assist the…
- [NTSB GAA17CA112](https://openairdocs.org/ntsb/GAA17CA112.md): Robinson Helicopter R22 · Champaign, IL · Accident · Minor injuries · Data collection · Final report · Jan 18, 2017 · N8042B · Substantial damage
  > The flight instructor’s failure to arrest the descent rate during the practice autorotation, which resulted in a hard landing.
- [NTSB CEN17LA091](https://openairdocs.org/ntsb/CEN17LA091.md): Beech 95-C55 · Delta, CO · Accident · No injuries · Limited investigation · Final report · Jan 18, 2017 · N303QB · Substantial damage
  > The failure of the landing gear to extend during landing approach due to the interference between the landing gear motor's sector and worm gears.
- [NTSB GAA17CA115](https://openairdocs.org/ntsb/GAA17CA115.md): American Champion 7GCAA · Bainbridge, GA · Accident · No injuries · Data collection · Final report · Jan 16, 2017 · N2540F · Substantial damage
  > The student pilot's exceedance of the airplane’s critical angle of attack during final approach, which resulted in an aerodynamic stall, and his subsequent loss of directional control after touchdown.
- [NTSB CEN17LA078](https://openairdocs.org/ntsb/CEN17LA078.md): Textron 525C · Howell, MI · Accident · Serious injuries · Limited investigation · Final report · Jan 16, 2017 · N525PZ · Substantial damage
  > The pilot's attempted landing on the ice-covered runway, which resulted in a runway excursion and impact with terrain. Contributing to the accident was airport personnel's lack of training regarding issuance of NOTAMs
- [NTSB GAA17CA113](https://openairdocs.org/ntsb/GAA17CA113.md): Aeronca 7AC · Compton, CA · Accident · No injuries · Data collection · Final report · Jan 15, 2017 · N1659E · Substantial damage
  > The pilot’s failure to maintain runway alignment during landing in gusting crosswind conditions, which resulted in an off-runway landing in soft dirt and a nose-over.
- [NTSB WPR17LA053](https://openairdocs.org/ntsb/WPR17LA053.md): Cessna T210 · Buckeye, AZ · Accident · Serious injuries · Class 3 · Limited · Final report · Jan 14, 2017 · N6366B · Substantial damage
  > The pilot's failure to maintain directional control of the airplane during the landing roll.
- [NTSB GAA17CA116](https://openairdocs.org/ntsb/GAA17CA116.md): Cessna 170 · Coeur D'Alene, ID · Accident · No injuries · Data collection · Final report · Jan 14, 2017 · N3210A · Substantial damage
  > The pilot’s failure to maintain an appropriate descent rate during approach, which resulted in landing short of the runway threshold.
- [NTSB GAA17CA122](https://openairdocs.org/ntsb/GAA17CA122.md): Cessna 172 · Punta Gorda, FL · Accident · No injuries · Data collection · Final report · Jan 12, 2017 · N10897 · Substantial damage
  > The student pilot’s failure to maintain proper pitch control, which resulted in a hard, bounced landing.
- [NTSB ERA17LA083](https://openairdocs.org/ntsb/ERA17LA083.md): Maule MX7 · Carthage, TN · Accident · Serious injuries · Limited investigation · Final report · Jan 11, 2017 · N3156K · Substantial damage
  > The pilot's inadequate compensation for gusting tailwind conditions, which resulted in a loss of airplane control during the landing flare.
- [NTSB ERA17WA084](https://openairdocs.org/ntsb/ERA17WA084.md): Cessna 172 · Tirua, Chile · Accident · 4 fatal · Foreign investigation · Jan 8, 2017 · CC-CMP · Destroyed
  > On January 8, 2017, about 1741 coordinated universal time (1441 local time), a Cessna 172, Chilean registration CC-CMP, was destroyed when it collided with terrain during final approach to Tirua Airport (SCQK), Tirua, Chile. The pilot and three passengers…
- [NTSB WPR17LA051](https://openairdocs.org/ntsb/WPR17LA051.md): Cessna 421C · Jackson, CA · Accident · No injuries · Limited investigation · Final report · Jan 7, 2017 · N71RC · Substantial damage
  > The failure of the right main landing gear torque link bolt in overstress, which resulted in the collapse of the landing gear during the landing roll.
- [NTSB GAA17CA111](https://openairdocs.org/ntsb/GAA17CA111.md): Cessna 172 · Hollywood, FL · Accident · No injuries · Data collection · Final report · Jan 7, 2017 · N907WA · Substantial damage
  > The student pilot’s improper landing flare in gusting crosswind conditions, which resulted in a hard landing.
- [NTSB CEN17LA082](https://openairdocs.org/ntsb/CEN17LA082.md): Cessna 172M · Hobart, IN · Accident · Serious injuries · Limited investigation · Final report · Jan 6, 2017 · N80374 · Substantial damage
  > The pilot's failure to abort the landing when he recognized the airplane was traveling too fast, which resulted in impact with trees off the end of the runway.
- [NTSB GAA17CA105](https://openairdocs.org/ntsb/GAA17CA105.md): Piper PA 46 · Nashville, TN · Accident · No injuries · Data collection · Final report · Dec 29, 2016 · N301BK · Substantial damage
  > The pilot’s loss of directional control during the aborted landing in gusting crosswind conditions, which resulted in a runway excursion.
- [NTSB CEN17WA069](https://openairdocs.org/ntsb/CEN17WA069.md): Sikorsky S92 · North Sea, UK, United Kingdom · Incident · No injuries · Foreign investigation · Dec 28, 2016 · G-WNSR
  > On December 28, 2016, G-WNSR, a Sikorsky S-92A helicopter had a heavy landing on the deck of an offshore platform in the North Sea. The 11 persons on-board were not injured. This accident/incident investigation is under the jurisdiction and control of the…
- [NTSB DCA17WA048](https://openairdocs.org/ntsb/DCA17WA048.md): Boeing 737 · Addis Ababa, Ethiopia · Incident · No injuries · Foreign investigation · Dec 25, 2016 · SU-GEA · Minor damage
  > The Ethiopia Accident Investigation Bureau (AIB) has notified the NTSB of an incident involving a Boeing 737-800 airplane that occurred on December 25, 2016. The NTSB has appointed a U.S. Accredited Representative to assist AIB's investigation under the…
- [NTSB GAA17CA104](https://openairdocs.org/ntsb/GAA17CA104.md): Cessna 172 · Palm Coast, FL · Accident · No injuries · Data collection · Final report · Dec 24, 2016 · N1289Y · Substantial damage
  > The student pilot’s improper landing flare, which resulted in a hard landing and porpoise.
- [NTSB GAA17CA100](https://openairdocs.org/ntsb/GAA17CA100.md): Cessna 150 · Warren, MN · Accident · No injuries · Data collection · Final report · Dec 23, 2016 · N7961F · Substantial damage
  > The noncertificated pilot’s failure to maintain directional control during the landing, which resulted in a runway excursion.
- [NTSB GAA17CA099](https://openairdocs.org/ntsb/GAA17CA099.md): Piper PA38 · Hartford, CT · Accident · Minor injuries · Data collection · Final report · Dec 23, 2016 · N250YA · Substantial damage
  > The student pilot’s improper landing flare, which resulted in a bounced hard landing.
- [NTSB CEN17LA070](https://openairdocs.org/ntsb/CEN17LA070.md): Aeronca 15AC · Pontiac, MI · Accident · No injuries · Limited investigation · Final report · Dec 23, 2016 · N1337H · Substantial damage
  > The improper installation of the left wheel brake torque plate by maintenance personnel, which resulted in the separation of the torque plate from the axle endplate and a loss of directional control during landing.
- [NTSB CEN17LA065](https://openairdocs.org/ntsb/CEN17LA065.md): Lueck Kitfox 7 · Cody, WY · Accident · No injuries · Limited investigation · Final report · Dec 23, 2016 · N320RJ · Substantial damage
  > Improper maintenance of the fuel pressure regulator, which resulted in an excessive fuel and airbox pressure differential and subsequent loss of engine power.
- [NTSB ANC17LA013](https://openairdocs.org/ntsb/ANC17LA013.md): Robinson Helicopter R22 · Palmer, AK · Accident · Minor injuries · Limited investigation · Final report · Dec 18, 2016 · N121MR · Substantial damage
  > The pilot's failure to maintain main rotor revolutions per minute (RPM) during a pinnacle landing, which resulted in a main rotor stall condition, a loss of control, and a subsequent impact with terrain. A contributing factor was the flight instructor's…
- [NTSB GAA17CA096](https://openairdocs.org/ntsb/GAA17CA096.md): Piper PA28 · Madisonville, TN · Accident · No injuries · Data collection · Final report · Dec 15, 2016 · N7646W · Substantial damage
  > The student pilot’s failure to maintain directional control during landing with a gusting crosswind.
- [NTSB DCA17WA078](https://openairdocs.org/ntsb/DCA17WA078.md): Boeing 737 · Kabul, Afghanistan · Accident · No injuries · Foreign investigation · Dec 12, 2016 · JY-JAQ · Substantial damage
  > The government of Afghanistan has notified the NTSB of an accident involving a BOEING 737 airplane that occurred on December 12, 2016. The NTSB has appointed a U.S. Accredited Representative to assist the government of Afghanistan's investigation under the…
- [NTSB WPR17LA037](https://openairdocs.org/ntsb/WPR17LA037.md): Beech A23 24 · Anacortes, WA · Accident · No injuries · Class 3 · Limited · Final report · Dec 11, 2016 · N7998L · Substantial damage
  > The pilot's failure to maintain directional control during the landing roll, which resulted in a runway excursion and separation of the left main landing gear.
- [NTSB CEN17LA055](https://openairdocs.org/ntsb/CEN17LA055.md): Hiller OH 23B · Tynan, TX · Accident · Serious injuries · Limited investigation · Final report · Dec 10, 2016 · N5776 · Destroyed
  > The student pilot's delayed and improper landing flare during a practice autorotation, which resulted in the tail rotor striking terrain.
- [NTSB GAA17CA094](https://openairdocs.org/ntsb/GAA17CA094.md): Schauer William A JR Starduster TOO SA300 · Kapolei, HI · Accident · No injuries · Data collection · Final report · Dec 8, 2016 · N2822T · Substantial damage
  > The pilot's failure to maintain directional control during the landing roll.
- [NTSB DCA17WA045](https://openairdocs.org/ntsb/DCA17WA045.md): Boeing 737 · Darwin, Australia · Incident · No injuries · Foreign investigation · Dec 6, 2016 · VH-VUI · Minor damage
  > The Australian Transport Safety Bureau (ATSB) has notified the NTSB of an incident involving a Boeing 737 airplane that occurred on December 06, 2016. The NTSB has appointed a U.S. Accredited Representative to assist the ATSB's investigation under the…
- [NTSB GAA17CA091](https://openairdocs.org/ntsb/GAA17CA091.md): Cessna 170 · Martinsville, VA · Accident · No injuries · Data collection · Final report · Dec 5, 2016 · N9002A · Substantial damage
  > The pilot's failure to maintain directional control during the landing roll.
- [NTSB CEN17LA047](https://openairdocs.org/ntsb/CEN17LA047.md): Cessna Citation 500 · Gunnison, CO · Accident · No injuries · Limited investigation · Final report · Dec 5, 2016 · N332SE · Substantial damage
  > The pilot’s failure to fly a stabilized approach and his inadequate landing flare, which resulted in a hard landing. Contributing to the accident was the pilot’s failure to ensure that the airplane was properly serviced with fuel before departing on the…
- [NTSB ENG17IA005](https://openairdocs.org/ntsb/ENG17IA005.md): Embraer ERJ170 200LR · San Antonio, TX · Incident · Minor injuries · Incident investigation · Final report · Dec 4, 2016 · N161SY · Minor damage
  > A failure of the nose landing gear down lock spring which precluded normal downlock operation of the nose landing gear. The spring failure was due to the presence of too much retained austenite which led to the formation of progressive cracking and subsequent…
- [NTSB GAA17CA139](https://openairdocs.org/ntsb/GAA17CA139.md): Piper PA46 · Midland, VA · Accident · No injuries · Data collection · Final report · Dec 2, 2016 · N4149R · Substantial damage
  > The pilot’s improper landing flare and subsequent hard landing while demonstrating a short-field landing and the flight instructor’s delayed remedial action.
- [NTSB ANC17LA011](https://openairdocs.org/ntsb/ANC17LA011.md): Robinson Helicopter R22 · Unalaska, AK · Accident · Minor injuries · Limited investigation · Final report · Dec 2, 2016 · N7085K · Substantial damage
  > The pilot’s failure to maintain adequate clearance from terrain during a precautionary landing in whiteout conditions, which resulted in an in-flight collision with terrain.
- [NTSB WPR17LA030](https://openairdocs.org/ntsb/WPR17LA030.md): Aero Commander 690 · Scottsdale, AZ · Accident · No injuries · Limited investigation · Final report · Dec 1, 2016 · N9175N · Substantial damage
  > The pilot’s loss of directional control during the landing roll, which resulted in the runway excursion onto the rock-covered runway safety area.
- [NTSB GAA17CA120](https://openairdocs.org/ntsb/GAA17CA120.md): Piper PA28 · St. Louis, MO · Accident · No injuries · Data collection · Final report · Nov 27, 2016 · N56809 · Substantial damage
  > The student pilot's improper landing flare, which resulted in a bounced landing.
- [NTSB GAA17WA583](https://openairdocs.org/ntsb/GAA17WA583.md): Bellanca 7GCBC · Budaors, Hungary · Incident · No injuries · Class 5 · Foreign · Nov 24, 2016 · HA-KYT
- [NTSB GAA17CA084](https://openairdocs.org/ntsb/GAA17CA084.md): American Legend AL3 · Pensacola, FL · Accident · No injuries · Data collection · Final report · Nov 23, 2016 · N155WB · Substantial damage
  > The student pilot’s incorrect brake application during the landing roll, which resulted in a loss of directional control.

Next page: https://openairdocs.org/ntsb-phases/550/cases.md?page=94

## The whole list in SQL

Runs in DuckDB 1.2 or later on the release's Parquet files over HTTPS:

```sql
WITH phase_names(main, name) AS (VALUES (100, 'Prior to flight'), (150, 'Standing'), (200, 'Pushback/towing'), (250, 'Taxi'), (300, 'Takeoff'), (350, 'Initial climb'), (400, 'Enroute'), (450, 'Maneuvering'), (500, 'Approach'), (550, 'Landing'), (600, 'Emergency descent'), (650, 'Uncontrolled descent'), (700, 'Post-impact'), (750, 'After landing'), (800, 'Other'), (990, 'Unknown')),
  crosswalk(code, main, name) AS (VALUES (500, 150, 'Standing'), (501, 150, 'Standing - pre-flight'), (502, 150, 'Standing - starting engine(s)'), (503, 150, 'Standing - engine(s) operating'), (504, 150, 'Standing - engine(s) not operating'), (505, 150, 'Standing - idling rotors'), (510, 250, 'Taxi'), (511, 200, 'Taxi - pushback/tow'), (512, 250, 'Taxi - to takeoff'), (513, 250, 'Taxi - from landing'), (514, 250, 'Taxi - aerial'), (520, 300, 'Takeoff'), (521, 300, 'Takeoff - roll/run'), (522, 350, 'Takeoff - initial climb'), (523, 300, 'Takeoff - aborted'), (530, 400, 'Climb'), (531, 400, 'Climb - to cruise'), (540, 400, 'Cruise'), (541, 400, 'Cruise - normal'), (542, 400, 'Maneuvering - holding (IFR)'), (550, 400, 'Descent'), (551, 400, 'Descent - normal'), (552, 600, 'Descent - emergency'), (553, 650, 'Descent - uncontrolled'), (560, 500, 'Approach'), (561, 500, 'Approach - VFR pattern - downwind'), (562, 500, 'Approach - VFR pattern - base turn'), (563, 500, 'Approach - VFR pattern - base leg/base to final'), (564, 500, 'Approach - VFR pattern - final approach'), (565, 500, 'Go-around (VFR)'), (566, 500, 'Approach - IAF to FAF/outer marker (IFR)'), (567, 500, 'Approach - FAF/outer marker to threshold (IFR)'), (568, 500, 'Circling (IFR)'), (569, 500, 'Missed approach (IFR)'), (570, 550, 'Landing'), (571, 550, 'Landing - flare/touchdown'), (572, 550, 'Landing - roll'), (573, 550, 'Landing - aborted'), (574, 550, 'Emergency landing'), (575, 550, 'Emergency landing after takeoff'), (576, 600, 'Emergency descent/landing'), (580, 450, 'Maneuvering'), (581, 450, 'Maneuvering - aerial application'), (582, 450, 'Maneuvering - turn to reverse direction'), (583, 450, 'Maneuvering - turn to landing area (emergency)'), (590, 450, 'Hover'), (591, 450, 'Hover - in ground effect'), (592, 450, 'Hover - out of ground effect'), (600, 800, 'Other'), (610, 990, 'Unknown')),
  current_codes AS (
    SELECT e.case_mkey, TRY_CAST(e."tier1Number" AS INTEGER) AS code,
      row_number() OVER (PARTITION BY e.case_mkey ORDER BY coalesce(e."isDefiningEvent", false) DESC, e.position) AS n
    FROM 'https://openairdocs.org/data/latest/ntsb_events.parquet' e
    WHERE e.aircrafts_position = 1 AND e."tier1Number" GLOB '[1-9][0-9]*'
      AND (e."isDefiningEvent" OR e.case_mkey IN (SELECT "mKey" FROM 'https://openairdocs.org/data/latest/ntsb_case_detail.parquet' WHERE "isPre1982"))
  ),
  phases AS (
    SELECT case_mkey, 'current' AS scheme, code, CASE WHEN code >= 990 THEN 990 ELSE code // 50 * 50 END AS main
    FROM current_codes WHERE n = 1
    UNION ALL
    SELECT o.case_mkey, 'older', o."phaseOfFlightCode", w.main
    FROM 'https://openairdocs.org/data/latest/ntsb_occurrences.parquet' o JOIN crosswalk w ON w.code = o."phaseOfFlightCode"
    WHERE o.aircrafts_position = 1 AND o."occurrenceNumber" = 1 AND o.case_mkey NOT IN (SELECT case_mkey FROM current_codes)
  ),
  case_phases AS (
    SELECT p.*, c."eventDate", c."highestInjuryLevel" = 'Fatal' AS fatal, a.aircraft_model_code
    FROM phases p JOIN 'https://openairdocs.org/data/latest/ntsb_case_detail.parquet' c ON c."mKey" = p.case_mkey
    LEFT JOIN 'https://openairdocs.org/data/latest/ntsb_aircrafts.parquet' a ON a.case_mkey = p.case_mkey AND a.position = 1
    WHERE c."eventDate" >= DATE '1962-01-01' AND p.main IN (SELECT main FROM phase_names)
  )
SELECT c."ntsbNumber", c."eventDate", c."eventType", c."eventCity", c."eventStateOrRegion", a.n_number, a."aircraftMake", a."aircraftModel", c."highestInjuryLevel", c."totalFatal", c."completionStatus", c.report_url
FROM 'https://openairdocs.org/data/latest/ntsb_case_detail.parquet' c LEFT JOIN 'https://openairdocs.org/data/latest/ntsb_aircrafts.parquet' a ON a.case_mkey = c."mKey" AND a.position = 1
WHERE c."mKey" IN (SELECT case_mkey FROM case_phases WHERE main = 550)
ORDER BY c."eventDate" DESC, c."ntsbNumber" DESC
```

This list as a web page: https://openairdocs.org/ntsb-phases/550/cases?page=93

---
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.
