# 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 76 of 1,075 · 53,702 cases

## Cases, newest first

- [NTSB GAA18CA531](https://openairdocs.org/ntsb/GAA18CA531.md): Piper PA44 · Centralia, IL · Accident · No injuries · Data collection · Final report · Sep 2, 2018 · N2204X · Substantial damage
  > The pilot receiving instruction's failure to extend the landing gear and the flight instructor's failure to verify that the landing gear was extended before landing. Contributing to the accident was the flight instructor’s delayed remedial action and…
- [NTSB GAA18CA522](https://openairdocs.org/ntsb/GAA18CA522.md): Piper PA 12 · Rexburg, ID · Accident · No injuries · Data collection · Final report · Sep 2, 2018 · N4077M · Substantial damage
  > The pilot's improper landing flare, which resulted in the airplane bouncing and a subsequent loss of directional control, a runway excursion, and impact with a fence.
- [NTSB CEN18LA364](https://openairdocs.org/ntsb/CEN18LA364.md): Lindstrand 77A · Brookfield, MO · Accident · Serious injuries · Limited investigation · Final report · Sep 2, 2018 · N370LB · No damage
  > The pilot's inability to maintain control of the balloon after encountering high wind conditions and windshear during the landing, which resulted in his ejection from the basket and serious injury to the passenger during the balloon’s subsequent impact with…
- [NTSB GAA18CA557](https://openairdocs.org/ntsb/GAA18CA557.md): Schweizer SGS 1 35 · Burnet, TX · Accident · No injuries · Data collection · Final report · Sep 1, 2018 · N34107 · Substantial damage
  > The pilot's failure to extend the landing gear before landing and to use the Before Landing checklist.
- [NTSB GAA18CA551](https://openairdocs.org/ntsb/GAA18CA551.md): Piper PA28 · Cypress, TX · Accident · No injuries · Data collection · Final report · Sep 1, 2018 · N212NA · Substantial damage
  > The student pilot’s improper approach path after the airplane encountered turbulence, which resulted in the airplane landing hard short of the runway.
- [NTSB GAA18CA550](https://openairdocs.org/ntsb/GAA18CA550.md): Boeing B75N1 · Culpeper, VA · Accident · No injuries · Data collection · Final report · Sep 1, 2018 · N27WE · Substantial damage
  > The pilot's failure to maintain directional control during the landing roll, which resulted in a ground-loop.
- [NTSB GAA18CA527](https://openairdocs.org/ntsb/GAA18CA527.md): Cessna 170 · Tulsa, OK · Accident · No injuries · Data collection · Final report · Sep 1, 2018 · N2303D · Substantial damage
  > The pilot’s failure to maintain directional control during landing in gusting crosswind conditions.
- [NTSB GAA18CA526](https://openairdocs.org/ntsb/GAA18CA526.md): Cessna 172 · Karluk, AK · Accident · No injuries · Data collection · Final report · Sep 1, 2018 · N3835S · Substantial damage
  > The pilot’s failure to maintain proper pitch for a soft-field landing, which resulted in a loss of airplane control.
- [NTSB DCA18WA277](https://openairdocs.org/ntsb/DCA18WA277.md): Boeing 737 · Sochi, Russia · Accident · Minor injuries · Foreign investigation · Sep 1, 2018 · VQ-BJI · Substantial damage
  > The Interstate Aviation Committee (MAK) of Russia has notified the NTSB of an accident involving a Boeing 737 airplane that occurred on September 01, 2018. The NTSB has appointed a U.S. Accredited Representative to assist the MAK of Russia's investigation…
- [NTSB CEN18LA361](https://openairdocs.org/ntsb/CEN18LA361.md): Beech 55 · Waupaca, WI · Accident · Serious injuries · Class 3 · Limited · Final report · Sep 1, 2018 · N10DS · Substantial damage
  > The total loss of engine power due to fuel exhaustion.
- [NTSB GAA18CA579](https://openairdocs.org/ntsb/GAA18CA579.md): Piper PA28 · Porterville, CA · Accident · Minor injuries · Data collection · Final report · Aug 31, 2018 · N8172N · Substantial damage
  > The pilot's failure to maintain directional control during the landing roll.
- [NTSB CEN18WA404](https://openairdocs.org/ntsb/CEN18WA404.md): Cessna 680 · Burgas, Bulgaria · Accident · No injuries · Class 5 · Foreign · Aug 31, 2018 · TC-OYD · Substantial damage
- [NTSB CEN18WA396](https://openairdocs.org/ntsb/CEN18WA396.md): Aero Designs Pulsar · Heapham, United Kingdom · Accident · No injuries · Foreign investigation · Aug 31, 2018 · G-LUED
  > On August 31, 2018, about 1700 coordinated universal time (UTC), an amateur-built Aero Designs Pulsar 1 airplane, United Kingdom registration G-LUED, serial number PFA 202-12122, was substantially damaged when it nosed-over after it overran the runway while…
- [NTSB CEN18LA360](https://openairdocs.org/ntsb/CEN18LA360.md): Stearman A75N1(PT17) · Kenosha, WI · Accident · No injuries · Limited investigation · Final report · Aug 31, 2018 · N64604 · Substantial damage
  > The failed retaining bolt and cracked backing plate, which resulted in a shift of the brake lining to contact the brake drum and a subsequent wheel lock when the brakes were applied.
- [NTSB DCA18WA287](https://openairdocs.org/ntsb/DCA18WA287.md): Boeing 747 · Hong Kong, Hong Kong SAR China · Incident · No injuries · Foreign investigation · Aug 30, 2018 · N415MC · Minor damage
  > The AAIA of Hong Kong has notified the NTSB of an accident involving a Boeing 747 airplane that occurred on August 30, 2018. The NTSB has appointed a U.S. Accredited Representative to assist the AAIA's investigation under the provisions of ICAO Annex 13 as…
- [NTSB CEN18WA379](https://openairdocs.org/ntsb/CEN18WA379.md): Piper PA32 · Belize City, Belize · Accident · No injuries · Foreign investigation · Aug 29, 2018 · N3073W · Substantial damage
  > On August 29, about 1804 local time (LCL), a Piper PA32 300 airplane, N3073W, operated by Wings of Hope, had a hard landing at the Sir Barry Bowen Municipal Airport, in Belize City, Belize. The airplane originated from the San Pedro Airport.This investigation…
- [NTSB GAA18CA529](https://openairdocs.org/ntsb/GAA18CA529.md): Piper PA46 · Hartford, CT · Accident · No injuries · Data collection · Final report · Aug 28, 2018 · N178DB · Substantial damage
  > The pilot’s unstabilized approach and hard landing, which resulted in a nose landing gear collapse.
- [NTSB GAA18CA524](https://openairdocs.org/ntsb/GAA18CA524.md): Luscombe 8 · Fulton, MO · Accident · No injuries · Data collection · Final report · Aug 28, 2018 · N1211B · Substantial damage
  > The pilot’s failure to maintain directional control during landing in gusting crosswind conditions.
- [NTSB GAA18CA513](https://openairdocs.org/ntsb/GAA18CA513.md): Cessna 172 · Winchester, VA · Accident · No injuries · Data collection · Final report · Aug 27, 2018 · N53051 · Substantial damage
  > The student pilot's failure to maintain directional control during the takeoff roll.
- [NTSB ERA18TA236](https://openairdocs.org/ntsb/ERA18TA236.md): Cessna 182 · Hanson, MA · Accident · No injuries · Final report · Aug 27, 2018 · N3115R · Substantial damage
  > The pilot's failure to attain the proper touchdown point, which resulted in a runway overrun. Contributing to the accident was the pilot's decision to land with a quartering tailwind.
- [NTSB GAA18CA554](https://openairdocs.org/ntsb/GAA18CA554.md): Airborne Edge X Classic · Lake Wales, FL · Accident · No injuries · Data collection · Final report · Aug 25, 2018 · N4557C · Substantial damage
  > The student pilot's improper landing flare, which resulted in a hard landing.
- [NTSB GAA18CA540](https://openairdocs.org/ntsb/GAA18CA540.md): Yakovlev YAK 52 · East Stroudsburg, PA · Accident · No injuries · Data collection · Final report · Aug 25, 2018 · N3042W · Substantial damage
  > The pilot's failure to extend the landing gear during landing, which resulted in a runway excursion and subsequent impact with terrain.
- [NTSB GAA18CA517](https://openairdocs.org/ntsb/GAA18CA517.md): Champion 7GCBC · Ocklawaha, FL · Accident · No injuries · Data collection · Final report · Aug 25, 2018 · N7618S · Substantial damage
  > The pilot’s failure to maintain directional control during landing.
- [NTSB GAA18CA516](https://openairdocs.org/ntsb/GAA18CA516.md): Piper PA28 · Point Lookout, MO · Accident · No injuries · Data collection · Final report · Aug 25, 2018 · N7635F · Substantial damage
  > The student pilot's inadvertent left brake application during the landing roll, which resulted in a runway excursion and collision with runway lights.
- [NTSB GAA18CA509](https://openairdocs.org/ntsb/GAA18CA509.md): Cessna 170 · Prineville, OR · Accident · No injuries · Data collection · Final report · Aug 25, 2018 · N4569C · Substantial damage
  > The pilot's failure to maintain directional control during the landing roll.
- [NTSB ANC18CA068](https://openairdocs.org/ntsb/ANC18CA068.md): Piper PA18 · Wasilla, AK · Accident · Minor injuries · Data collection · Final report · Aug 25, 2018 · N5392Y · Substantial damage
  > The pilot's failure to maintain directional control during the landing roll when the left main landing gear wheel got caught in a ditch, which resulted in a subsequent nose-over.
- [NTSB GAA18CA510](https://openairdocs.org/ntsb/GAA18CA510.md): Maule MX7 · Post Mills, VT · Accident · No injuries · Data collection · Final report · Aug 24, 2018 · N524TR · Substantial damage
  > The pilot's failure to maintain directional control during landing, which resulted in a runway excursion and subsequent impact with trees.
- [NTSB GAA18CA508](https://openairdocs.org/ntsb/GAA18CA508.md): Robinson R22 · Corvallis, OR · Accident · Minor injuries · Data collection · Final report · Aug 24, 2018 · N4085T · Substantial damage
  > The student helicopter pilot’s inadequate torque pedal application during practice approaches with a tailwind, which resulted in a loss of yaw control and a subsequent hard landing.
- [NTSB CEN18WA366](https://openairdocs.org/ntsb/CEN18WA366.md): Cirrus SR22 · Balchik, Bulgaria · Accident · 1 fatal · Foreign investigation · Aug 24, 2018 · LZ-SEV · Destroyed
  > On August 24, 2018, at 1608 coordinated universal time, a Cirrus SR22, LZ-SEV, impacted terrain at the Balchik Airfield (LBWB), Balchik, Bulgaria. The airplane was destroyed. The pilot was fatally injured. The flight originated from Lesnovo Airport (LBLS),…
- [NTSB GAA18CA505](https://openairdocs.org/ntsb/GAA18CA505.md): Cessna 172 · Churchville, MD · Accident · No injuries · Data collection · Final report · Aug 23, 2018 · N419SP · Substantial damage
  > The pilot's failure to maintain directional control after landing left of the runway centerline, which resulted in a runway excursion and impact with a power box.
- [NTSB GAA18CA499](https://openairdocs.org/ntsb/GAA18CA499.md): Evolution Trikes Revo · Hawthorne, CA · Accident · Minor injuries · Data collection · Final report · Aug 21, 2018 · N145PT · Substantial damage
  > The flight instructor’s failure to maintain lateral control of the weight-shift-controlled aircraft during the landing flare.
- [NTSB GAA18CA547](https://openairdocs.org/ntsb/GAA18CA547.md): Cessna 172 · Burlington, VT · Accident · No injuries · Data collection · Final report · Aug 20, 2018 · N557SP · Substantial damage
  > The student pilot’s improper landing flare, which resulted in a bounced landing.
- [NTSB GAA18CA501](https://openairdocs.org/ntsb/GAA18CA501.md): Cessna A185 · McCall, ID · Accident · No injuries · Data collection · Final report · Aug 20, 2018 · N93039 · Substantial damage
  > The disconnection of the brake cylinder actuator rod, which resulted in the pilot’s inability to maintain directional control during the landing roll.
- [NTSB CEN18LA341](https://openairdocs.org/ntsb/CEN18LA341.md): Cirrus SR22 · Granbury, TX · Accident · Minor injuries · Limited investigation · Final report · Aug 20, 2018 · N1133T · Substantial damage
  > The pilot’s failure to maintain directional control during a crosswind landing, which resulted in the airplane exiting the runway and impacting a ditch, tree, and fence.
- [NTSB GAA18CA518](https://openairdocs.org/ntsb/GAA18CA518.md): Rans Rans S6S · Painton, MO · Accident · Minor injuries · Data collection · Final report · Aug 19, 2018 · N107SJ · Substantial damage
  > The pilot's failure to maintain the proper pitch attitude during landing, which resulted in a bounced, hard landing.
- [NTSB DCA18WA314](https://openairdocs.org/ntsb/DCA18WA314.md): De Havilland DHC8 · Callao, Peru · Accident · No injuries · Foreign investigation · Aug 19, 2018 · N404AV · Substantial damage
  > The Peru Comisión de Investigación de Accidentes Aviación ((CIAA) has notified the NTSB of an accident involving a De Havilland DHC8 that occurred on August 19, 2018. The NTSB has appointed a U.S. Accredited Representative to assist the CIAA'S investigation…
- [NTSB GAA18CA497](https://openairdocs.org/ntsb/GAA18CA497.md): Piper PA18 · Stony RIver, AK · Accident · No injuries · Data collection · Final report · Aug 18, 2018 · N3872Z · Substantial damage
  > The pilot's selection of unsuitable terrain for landing, which resulted in a nose-over.
- [NTSB DCA18WA280](https://openairdocs.org/ntsb/DCA18WA280.md): Boeing 737 · Los Cabos, Mexico · Incident · No injuries · Foreign investigation · Aug 18, 2018 · N337PJ · No damage
  > The government of Mexico has notified the NTSB of an accident involving a Boeing 737 airplane that occurred on August 18, 2018. The NTSB has appointed a U.S. Accredited Representative to assist the government of Mexico's investigation under the provisions of…
- [NTSB ANC18LA067](https://openairdocs.org/ntsb/ANC18LA067.md): Cessna U206 · Pedro Bay, AK · Accident · No injuries · Limited investigation · Final report · Aug 18, 2018 · N441GR · Substantial damage
  > The fatigue fracture of both main landing gear legs during the landing roll, which resulted in the collapse and separation of both main landing gear legs.
- [NTSB GAA18CA495](https://openairdocs.org/ntsb/GAA18CA495.md): Cessna 140 · Hayes Center, NE · Accident · No injuries · Data collection · Final report · Aug 17, 2018 · N4102N · Substantial damage
  > The pilot's failure to maintain directional control during landing.
- [NTSB ANC18WA077](https://openairdocs.org/ntsb/ANC18WA077.md): Cessna U206 · Fort Simpson, Canada · Accident · 3 fatal · Foreign investigation · Aug 17, 2018 · C-FNEQ · Substantial damage
  > On August 17, 2018, about 0035 Coordinated Universal Time, an amphibious float-equipped Cessna U206G airplane, C-FNEQ, nosed over while landing at Little Doctor Lake near Fort Simpson, Northwest Territories, Canada. Of the five souls onboard, the pilot and…
- [NTSB DCA18WA268](https://openairdocs.org/ntsb/DCA18WA268.md): Boeing 737 · Manila, Philippines · Accident · No injuries · Foreign investigation · Aug 16, 2018 · B-5498 · Minor damage
  > The CAA of the Philippines has notified the NTSB of an incident involving a Boeing 737 airplane that occurred on August 16, 2018. The NTSB has appointed a U.S. Accredited Representative to assist the CAA's investigation under the provisions of ICAO Annex 13…
- [NTSB GAA18CA520](https://openairdocs.org/ntsb/GAA18CA520.md): Piper PA18 · Tyonek, AK · Accident · No injuries · Data collection · Final report · Aug 15, 2018 · N4165Z · Substantial damage
  > The pilot’s failure to maintain directional control during landing in gusting wind conditions.
- [NTSB GAA18CA493](https://openairdocs.org/ntsb/GAA18CA493.md): Cessna 172 · Silver City, NM · Accident · Minor injuries · Data collection · Final report · Aug 15, 2018 · N1543Y · Substantial damage
  > The pilot’s failure to maintain directional control while landing with a quartering tailwind.
- [NTSB GAA18CA492](https://openairdocs.org/ntsb/GAA18CA492.md): Cessna 180 · Ambler, AK · Accident · No injuries · Data collection · Final report · Aug 15, 2018 · N9949N · Substantial damage
  > The pilot's selection of unsuitable terrain for landing, which resulted in the left wing and horizontal stabilizer striking the ground.
- [NTSB ERA18LA220](https://openairdocs.org/ntsb/ERA18LA220.md): Czech Sport Piper Sport · Stuart, FL · Accident · No injuries · Limited investigation · Final report · Aug 15, 2018 · N425AZ · Substantial damage
  > Inadequate maintenance inspection of the airplane's nose landing gear, which resulted in a nose landing gear collapse during landing due to cracking and corrosion.
- [NTSB DCA18IA269](https://openairdocs.org/ntsb/DCA18IA269.md): DJI Phantom · Blacksburg, VA · Incident · Minor injuries · Incident investigation · Final report · Aug 14, 2018 · FA3HCWCR4X · Minor damage
  > the drone pilot's incorrect control inputs due to insufficient knowledge of the aircraft flight manual procedures. Contributing to the incident was the close proximity of the observers, and the decision to conduct a demonstration near the observers in a…
- [NTSB DCA18CA283](https://openairdocs.org/ntsb/DCA18CA283.md): Airbus A321-271N · Los Angeles, CA · Accident · No injuries · Class 4 · Data collection · Final report · Aug 13, 2018 · N204HA · Substantial damage
  > a tailstrike caused by inappropriate recovery technique after a bounced landing. Contributing to the accident was the failure of the radio altimeter, caused by the approach being over calm/flat water, that was not recognized by the flight crew.
- [NTSB CEN18TA330](https://openairdocs.org/ntsb/CEN18TA330.md): Piper J3C · Friendswood, TX · Accident · No injuries · Final report · Aug 13, 2018 · N42218 · Substantial damage
  > The pilot's decision to conduct a flight in an airplane that had a tailwheel with degraded locking pins, which allowed the tailwheel to unlock and swivel out of alignment and precluded the pilot from regaining directional control on the ground during a…
- [NTSB ERA18LA214](https://openairdocs.org/ntsb/ERA18LA214.md): Pipistrel Sinus 912 · West Palm Beach, FL · Accident · No injuries · Class 3 · Limited · Final report · Aug 12, 2018 · N467L · Destroyed
  > The fatigue failure of the exhaust system manifold, which resulted in a ground fire after landing.

Next page: https://openairdocs.org/ntsb-phases/550/cases.md?page=77

## 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=76

---
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.
