# NTSB investigations: Approach

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 63 of 420 · 20,992 cases

## Cases, newest first

- [NTSB ERA09WA153](https://openairdocs.org/ntsb/ERA09WA153.md): Cessna 421B · Nassau, Bahamas · Accident · Minor injuries · Foreign investigation · Jan 30, 2009 · C6-DXL · Substantial damage
  > On January 29, 2009, at 2130 eastern daylight time, a Cessna 421B, Bahamian registration C6-DXL, operated by a private individual as an air ambulance, experienced a loss of engine power while on approach to the Lynden Pindling International Airport (MYNN),…
- [NTSB ERA09FA148](https://openairdocs.org/ntsb/ERA09FA148.md): Cirrus Design SR22 · Moncks Corner, SC · Accident · 1 fatal · Field investigation · Final report · Jan 29, 2009 · N224SB · Substantial damage
  > A loss of aircraft control during the landing approach for undetermined reasons.
- [NTSB CEN09MA142](https://openairdocs.org/ntsb/CEN09MA142.md): Aerospatiale Alenia ATR 42-320 · Lubbock, TX · Accident · Serious injuries · Class 1 · Major · Final report · Jan 27, 2009 · N902FX · Substantial damage
  > The flight crew's failure to monitor and maintain a minimum safe airspeed while executing an instrument approach in icing conditions, which resulted in an aerodynamic stall at low altitude. Contributing to the accident were 1) the flight crew's failure to…
- [NTSB ERA09CA142](https://openairdocs.org/ntsb/ERA09CA142.md): Cessna 152 · Titusville, FL · Accident · No injuries · Data collection · Final report · Jan 25, 2009 · N48570 · Substantial damage
  > A loss of engine power during approach due to fuel exhaustion as a result of the pilot's inadequate fuel planning.
- [NTSB WPR09CA092](https://openairdocs.org/ntsb/WPR09CA092.md): Ryan Navion · Three Forks, MT · Accident · No injuries · Data collection · Final report · Jan 19, 2009 · N4443K · Substantial damage
  > A total loss of engine power due to fuel starvation as a result of the pilot's inadequate fuel system management. Contributing to the accident were the pilot's diverted attention and failure to perform the prelanding checklist.
- [NTSB CEN09LA137](https://openairdocs.org/ntsb/CEN09LA137.md): Beech A36 · Farmington, NM · Accident · No injuries · Limited investigation · Final report · Jan 18, 2009 · N8074P · Substantial damage
  > Collapse of the landing gear during landing due to the incorrect installation of the landing gear actuator. Contributing to the accident was the pilot's failure to initiate the abnormal procedures checklist prior to landing.
- [NTSB ERA09LA137](https://openairdocs.org/ntsb/ERA09LA137.md): Piper PA-28-180 · Jasper, GA · Accident · No injuries · Limited investigation · Final report · Jan 17, 2009 · N9459J · Substantial damage
  > A total loss of engine power for an undetermined reason.
- [NTSB CEN09FA135](https://openairdocs.org/ntsb/CEN09FA135.md): Gulfstream Aerospace Commander · Wray, CO · Accident · 3 fatal · Field investigation · Final report · Jan 15, 2009 · N840NK · Destroyed
  > The pilot’s failure to maintain aircraft control during the approach resulting in an aerodynamic stall and subsequent impact with terrain. Contributing to the accident was the pilot’s improper preflight planning and conditions conducive for structural icing.
- [NTSB ERA09CA134](https://openairdocs.org/ntsb/ERA09CA134.md): Piper PA-32R-300 · Manteo, NC · Accident · Serious injuries · Data collection · Final report · Jan 13, 2009 · N7918C · Substantial damage
  > The pilot's failure to follow the missed approach procedure while landing with a low ceiling.
- [NTSB ERA09CA171](https://openairdocs.org/ntsb/ERA09CA171.md): Cessna 120 · Woodstock, GA · Accident · No injuries · Data collection · Final report · Jan 12, 2009 · N57N · Substantial damage
  > A loss of engine power, as reported by the pilot, for undetermined reasons.
- [NTSB WPR09LA083](https://openairdocs.org/ntsb/WPR09LA083.md): Cessna 172RG · Carson City, NV · Accident · No injuries · Limited investigation · Final report · Jan 10, 2009 · N6272R · Substantial damage
  > The overload failure of the landing gear actuator at an undetermined time.
- [NTSB CEN09LA124](https://openairdocs.org/ntsb/CEN09LA124.md): Lavigna Lancair IV P · Iola, KS · Accident · Minor injuries · Limited investigation · Final report · Jan 7, 2009 · N131DL · Destroyed
  > The total loss of engine power for undetermined reasons.
- [NTSB WPR09FA072](https://openairdocs.org/ntsb/WPR09FA072.md): Eurocopter AS 350 BA · Honolulu, HI · Accident · No injuries · Field investigation · Final report · Jan 5, 2009 · N141MK · Substantial damage
  > The partial loss of engine power during landing for an undetermined reason.
- [NTSB ERA09LA130](https://openairdocs.org/ntsb/ERA09LA130.md): Cessna 550 · Wilmington, NC · Accident · No injuries · Limited investigation · Final report · Jan 4, 2009 · N815MA · Substantial damage
  > A loss of engine power due to the crew's inadequate in-flight fuel monitoring.
- [NTSB ERA09LA124](https://openairdocs.org/ntsb/ERA09LA124.md): Piper PA-28-160 · Indiana, PA · Accident · 1 fatal · Limited investigation · Final report · Jan 4, 2009 · N5212W · Substantial damage
  > The pilot's decision to attempt VFR flight in IMC conditions, resulting in a collision with trees during a go-around.
- [NTSB CEN09FA115](https://openairdocs.org/ntsb/CEN09FA115.md): Nanchang China CJ-6 · Justin, TX · Accident · 2 fatal · Field investigation · Final report · Jan 3, 2009 · N99YK · Destroyed
  > The pilot's failure to maintain adequate airspeed while maneuvering on approach, which resulted in an accelerated stall and subsequent loss of control.
- [NTSB ERA09FA116](https://openairdocs.org/ntsb/ERA09FA116.md): Piper PA-28-140 · Pittstown, NJ · Accident · 1 fatal · Field investigation · Final report · Dec 31, 2008 · N95156 · Substantial damage
  > The pilot's failure to maintain an adequate clearance from trees during the night landing approach and the flight instructor's inadequate remedial action.
- [NTSB CEN09CA123](https://openairdocs.org/ntsb/CEN09CA123.md): Cessna T210M · Fort Collins, CO · Accident · No injuries · Data collection · Final report · Dec 31, 2008 · N732YK · Substantial damage
  > A total loss of engine power due to fuel starvation as a result of the pilot's failure to select the fullest tank before landing.
- [NTSB ERA09LA106](https://openairdocs.org/ntsb/ERA09LA106.md): Reamer RV7A · Wadesboro, NC · Accident · 1 fatal · Limited investigation · Final report · Dec 25, 2008 · N675RV · Substantial damage
  > The pilot's failure to maintain adequate airspeed while on approach for a precautionary landing, which resulted in an aerodynamic stall.
- [NTSB CEN09CA118](https://openairdocs.org/ntsb/CEN09CA118.md): Socata TBM 700 · Clovis, NM · Accident · No injuries · Data collection · Final report · Dec 23, 2008 · N70LR · Substantial damage
  > The pilot's failure to complete the before-landing checklist, which led to his failure to lower the gear before landing.
- [NTSB CEN09FA098](https://openairdocs.org/ntsb/CEN09FA098.md): Piper PA-46 · Hayden, CO · Accident · 2 fatal · Field investigation · Final report · Dec 22, 2008 · N46SB · Destroyed
  > The pilot's loss of situational awareness while maneuvering in adverse weather conditions, resulting in spatial disorientation.
- [NTSB CEN09FA099](https://openairdocs.org/ntsb/CEN09FA099.md): Piper PA-32R · North Canton, OH · Accident · 1 fatal · Field investigation · Final report · Dec 19, 2008 · N9299N · Destroyed
  > The pilot’s inappropriate control inputs as a result of spatial disorientation, which led to an aerodynamic stall and loss of control. Contributing to the accident were the pilot's decision to conduct flight into known icing conditions, ice accumulation that…
- [NTSB ERA09FA093](https://openairdocs.org/ntsb/ERA09FA093.md): Beech 36 · Louisville, KY · Accident · 1 fatal · Field investigation · Final report · Dec 18, 2008 · N7472N · Substantial damage
  > The pilot’s continued operation of the aircraft with known deficiencies. Contributing to this accident was the improper sealing of the engine case during overhaul.
- [NTSB CEN09LA095](https://openairdocs.org/ntsb/CEN09LA095.md): Cessna 402 · Madison, WI · Accident · No injuries · Limited investigation · Final report · Dec 17, 2008 · N4504B · Substantial damage
  > The pilot’s improper fuel management, which resulted in a loss of engine power during an instrument landing due to fuel exhaustion.
- [NTSB CEN09FA094](https://openairdocs.org/ntsb/CEN09FA094.md): Bombardier CL-600-2C10 · Chicago, IL · Incident · No injuries · Field investigation · Final report · Dec 16, 2008 · N511MJ · Minor damage
  > The failure of the left landing gear to extend due to improper maintenance when the landing gear door was replaced. Contributing to the incident was the manufacturer's inadequate maintenance manual instructions.
- [NTSB DCA09IA017](https://openairdocs.org/ntsb/DCA09IA017.md): Bombardier CL-600-2B19 · Philadelphia, PA · Incident · No injuries · Incident investigation · Final report · Dec 14, 2008 · N407AW · Minor damage
  > the failure of the maintenance personnel to properly complete the installation, and the inspection personnel to conduct the proper functional test, of the left main landing gear uplock assembly.
- [NTSB WPR09LA056](https://openairdocs.org/ntsb/WPR09LA056.md): Cessna 172 · Lompoc, CA · Accident · 1 fatal · Limited investigation · Final report · Dec 10, 2008 · N6461E · Substantial damage
  > The pilot's failure to maintain clearance from the power line. Contributing to the accident was the pilot's lack of recent experience.
- [NTSB CEN09WA082](https://openairdocs.org/ntsb/CEN09WA082.md): Learjet Lear 23 · Tlaxcala, Mexico · Accident · 2 fatal · Foreign investigation · Dec 8, 2008 · XC-LGD · Substantial damage
  > On December 7, 2008 at approximately 1815 central standard time (CST) a twin-engine turbo fan, Learjet 23, Mexican Registration XC-LGD, was destroyed when it impacted a lake while on final approach to an unlit day visual flight rules airport near Tlaxcala,…
- [NTSB ERA09LA081](https://openairdocs.org/ntsb/ERA09LA081.md): Merrell Stephen F1 Rocket · Sebastian, FL · Accident · No injuries · Limited investigation · Final report · Dec 7, 2008 · N757SM · Substantial damage
  > A loss of engine power due to fuel starvation as a result of the pilot's incorrect positioning of the fuel selector valve.
- [NTSB ERA09CA073](https://openairdocs.org/ntsb/ERA09CA073.md): Extra Flugzeugbau EA 300/L · Tampa, FL · Accident · Minor injuries · Data collection · Final report · Nov 28, 2008 · N505EX · Substantial damage
  > The pilot's inadequate visual lookout, which resulted in a collision with an object.
- [NTSB WPR09LA049](https://openairdocs.org/ntsb/WPR09LA049.md): Raytheon G36 · Porterville, CA · Accident · Serious injuries · Limited investigation · Final report · Nov 27, 2008 · N936EW · Substantial damage
  > A loss of engine power for undetermined reasons.
- [NTSB ERA09CA077](https://openairdocs.org/ntsb/ERA09CA077.md): Cessna 172I · Frederick, MD · Accident · No injuries · Data collection · Final report · Nov 27, 2008 · N35540 · Substantial damage
  > The student pilot's delayed decision to abort the landing.
- [NTSB WPR09LA046](https://openairdocs.org/ntsb/WPR09LA046.md): Piper PA-28-180 · Monterey, CA · Accident · Serious injuries · Limited investigation · Final report · Nov 26, 2008 · N2383R · Substantial damage
  > The pilot's inadequate fuel system management and inflight planning that led to a loss of engine power due to fuel exhaustion. Contributing to the accident was the pilot's failure to use the landing checklist.
- [NTSB ERA09FA068](https://openairdocs.org/ntsb/ERA09FA068.md): Beech 95-B55 (T4 · Whites Creek, TN · Accident · 3 fatal · Field investigation · Final report · Nov 24, 2008 · N412ES · Destroyed
  > The pilot's failure to feather the left propeller and secure the left engine following the total loss of left engine power, and his subsequent failure to maintain airspeed, lateral, and directional control of the airplane. Contributing to the accident was the…
- [NTSB ERA09LA067](https://openairdocs.org/ntsb/ERA09LA067.md): Beech V35 · Winter Haven, FL · Accident · No injuries · Limited investigation · Final report · Nov 23, 2008 · N4396W · 2 aircraft · Substantial damage
  > Both pilots’ failure to see and avoid the other airplane. Contributing to the accident was the Beech pilot’s failure to monitor or utilize the common traffic advisory frequency.
- [NTSB CEN09FA070](https://openairdocs.org/ntsb/CEN09FA070.md): Piper PA46-500TP · Marshfield, WI · Accident · 3 fatal · Field investigation · Final report · Nov 23, 2008 · N67TE · Destroyed
  > The pilot's failure to maintain control of the airplane during final approach for landing in night, visual meteorological conditions for undetermined reasons.
- [NTSB ERA09LA064](https://openairdocs.org/ntsb/ERA09LA064.md): Cessna 172S · Groton, CT · Accident · Minor injuries · Limited investigation · Final report · Nov 19, 2008 · N2337F · Substantial damage
  > The student pilot’s failure to maintain a proper descent profile to avoid trees during the night visual approach and the flight instructor’s inadequate oversight.
- [NTSB ERA09FA060](https://openairdocs.org/ntsb/ERA09FA060.md): Piper PA-38-112 · Smithfield, RI · Accident · 2 fatal · Field investigation · Final report · Nov 17, 2008 · N2316P · Substantial damage
  > The pilot's improper descent below the published minimum descent altitude during the approach, which resulted in controlled flight into terrain.
- [NTSB ERA09IA056](https://openairdocs.org/ntsb/ERA09IA056.md): DeHavilland DHC-8-311 · Philadelphia, PA · Incident · No injuries · Incident investigation · Final report · Nov 16, 2008 · N326EN · Minor damage
  > The mechanical overload of the nosewheel steering links for undetermined reasons, which resulted in nose landing gear rotation and its subsequent wedging within the wheel well structure.
- [NTSB CEN09LA061](https://openairdocs.org/ntsb/CEN09LA061.md): Cessna 182 · Downers Grove, IL · Accident · Minor injuries · Limited investigation · Final report · Nov 16, 2008 · N759HF · Substantial damage
  > The pilot's failure to maintain a proper glidepath while on final approach in night conditions, due to his impairment from recent use of alcohol, cocaine, and over-the-counter and prescription medications.
- [NTSB ERA09FA053](https://openairdocs.org/ntsb/ERA09FA053.md): Cirrus Design SR22 · Tallahassee, FL · Accident · 2 fatal · Field investigation · Final report · Nov 14, 2008 · N827GM · Substantial damage
  > The pilot's failure to maintain adequate airspeed on final approach, which resulted in a low-altitude aerodynamic stall and spin. Contributing to the accident was the pilot's failure to fly the published instrument approach and his subsequent failure to…
- [NTSB ANC09LA011](https://openairdocs.org/ntsb/ANC09LA011.md): Cessna 152 · Fairbanks, AK · Accident · No injuries · Limited investigation · Final report · Nov 14, 2008 · N47417 · 2 aircraft · Minor damage
  > The failure of the instructor pilot in the other airplane to maintain separation from the Cessna 182R, and his failure to follow the tower controller’s instructions.
- [NTSB ERA09FA039](https://openairdocs.org/ntsb/ERA09FA039.md): Partenavia P.68C · Gainesville, FL · Accident · 3 fatal · Field investigation · Final report · Nov 7, 2008 · N681KW · Substantial damage
  > The pilot's failure to maintain the proper glidepath during an instrument-landing-system (ILS) approach. Contributing to the accident were the pilot's decision to initiate the ILS approach with weather below the published minimums, and the pilot's…
- [NTSB ERA09CA038](https://openairdocs.org/ntsb/ERA09CA038.md): Beech 35-C33 · Atlanta, GA · Accident · No injuries · Data collection · Final report · Nov 5, 2008 · N5891J · Substantial damage
  > The pilot’s failure to maintain a proper glide path during the final approach, resulting in a collision with the airport approach lights.
- [NTSB CEN09CA053](https://openairdocs.org/ntsb/CEN09CA053.md): Cessna 172F · Hutchinson, MN · Accident · No injuries · Data collection · Final report · Nov 5, 2008 · N5556R · Substantial damage
  > The bird that the airplane struck while on final approach.
- [NTSB ANC09LA009](https://openairdocs.org/ntsb/ANC09LA009.md): Construcciones Aeronauticas CASA-212 · Toksook Bay, AK · Accident · Minor injuries · Limited investigation · Final report · Nov 2, 2008 · N437RA · Substantial damage
  > The flight crew’s inability to adjust/increase power to the right engine during the landing approach due to an in-flight disconnect of the engine power control linkage, resulting in a loss of control of the airplane. Contributing to the accident was the…
- [NTSB ERA09LA033](https://openairdocs.org/ntsb/ERA09LA033.md): Piper PA-32-260 · Plymouth, NC · Accident · Minor injuries · Limited investigation · Final report · Nov 1, 2008 · N3568W · 2 aircraft · Substantial damage
  > The Piper Dakota (PA-28-236) pilot's failure to see and avoid the Piper Cherokee (PA-32-260).
- [NTSB ERA09CA046](https://openairdocs.org/ntsb/ERA09CA046.md): Hilderson Oswald Aventura HP · Weirwood, VA · Accident · No injuries · Data collection · Final report · Oct 31, 2008 · N1932H · Substantial damage
  > The pilot's failure to maintain control of the airplane following an in-flight encounter with turbulence during approach, which led to a loss of engine power due to fuel starvation, and subsequent forced landing into trees.
- [NTSB WPR09LA029](https://openairdocs.org/ntsb/WPR09LA029.md): Cessna 421C · Mesa, AZ · Accident · No injuries · Limited investigation · Final report · Oct 30, 2008 · N421PC · Substantial damage
  > The failure of the hydraulic landing gear extension systems due to a ruptured line.
- [NTSB WPR09FA027](https://openairdocs.org/ntsb/WPR09FA027.md): Cessna P206 · Estacada, OR · Accident · 2 fatal · Field investigation · Final report · Oct 29, 2008 · N2570X · Substantial damage
  > The pilot's failure to maintain clearance from trees while on approach to land at night. Contributing to the accident was the electrical system failure and the pilot's diverted attention.

Next page: https://openairdocs.org/ntsb-phases/500/cases.md?page=64

## 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 = 500)
ORDER BY c."eventDate" DESC, c."ntsbNumber" DESC
```

This list as a web page: https://openairdocs.org/ntsb-phases/500/cases?page=63

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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.
