# NTSB investigations, CO: Emergency descent

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.

## Latest cases

- [NTSB CEN26LA181](https://openairdocs.org/ntsb/CEN26LA181.md): Hughes 369HS · Durango, CO · Accident · No injuries · Class 4 · Limited · Final report · May 7, 2026 · N926ES · Substantial damage
  > The flight instructor’s inadequate supervision of the pilot receiving the instruction and the pilot’s improper recovery from a practice autorotation in shifting wind conditions, which resulted in a hard landing.
- [NTSB CEN25LA003](https://openairdocs.org/ntsb/CEN25LA003.md): Schweizer 269C · Montrose, CO · Accident · Minor injuries · Class 3 · Limited · Final report · Oct 3, 2024 · N656RB · Substantial damage
  > A loss of engine power during a demonstrated autorotation due to an improperly adjusted air-fuel mixture or idle setting. Contributing to the accident was the pilot’s failure to perform the required idle check during previous flights in higher elevation areas.
- [NTSB CEN23LA048](https://openairdocs.org/ntsb/CEN23LA048.md): Hughes 369HS · Oxford, CO · Accident · No injuries · Class 4 · Limited · Final report · Nov 23, 2022 · N668M · Substantial damage
  > The designated pilot examiner’s failure to maintain a proper descent during a practice 180° autorotation which resulted in a hard landing.
- [NTSB CEN15FA126](https://openairdocs.org/ntsb/CEN15FA126.md): Enstrom 280FX · Erie, CO · Accident · 2 fatal · Field investigation · Final report · Jan 26, 2015 · N86235 · Destroyed
  > An in-flight failure of the helicopter's #2 main rotor spindle due to undetected fatigue cracking, which resulted in an in-flight breakup. Contributing to failure were the nonconforming thread root radius of the spindle and the manufacturer's failure to…
- [NTSB CEN14FA173](https://openairdocs.org/ntsb/CEN14FA173.md): Worthington Donald Wayne Sonerai II LT · Highlands Ranch, CO · Accident · 1 fatal · Field investigation · Final report · Mar 29, 2014 · N63917 · Destroyed
  > The pilot’s loss of control during a forced landing following a loss of engine power for reasons that could not be determined due to postimpact fire damage.
- [NTSB CEN11CA068](https://openairdocs.org/ntsb/CEN11CA068.md): Schweizer 300C · Broomfield, CO · Accident · No injuries · Data collection · Final report · Nov 14, 2010 · N299RJ · Substantial damage
  > The pilot’s inadequate fuel planning, which resulted in a loss of engine power due to fuel exhaustion. Contributing to the accident was the pilot's improper execution of an autorotation, which resulted in a hard landing.
- [NTSB CEN10LA056](https://openairdocs.org/ntsb/CEN10LA056.md): Navion Navion G · Montrose, CO · Accident · Minor injuries · Limited investigation · Final report · Nov 18, 2009 · N2493T · Substantial damage
  > A loss of engine power due to the pilot’s inadequate preflight planning.
- [NTSB DEN04LA082](https://openairdocs.org/ntsb/DEN04LA082.md): Lockheed TV-2 · Calhan, CO · Accident · No injuries · Limited investigation · Final report · May 29, 2004 · N6617 · Substantial damage
  > the failure of the fuel tank float which resulted in the draining of fuel out the vents, and a low fuel supply. Contributing factors include the insufficient runway length, the ditch, and the rough, uneven terrain.
- [NTSB DEN00FA028](https://openairdocs.org/ntsb/DEN00FA028.md): Hughes 369D · Peyton, CO · Accident · No injuries · Field investigation · Final report · Dec 15, 1999 · N5190C · Substantial damage
  > an uncontrolled touchdown following entry into a "out-of-ground effect" hover. Factors were loss of tail rotor effectiveness, and the pilot's lack of recent experience in kind of aircraft and total experience in type of aircraft.
- [NTSB DEN99LA146](https://openairdocs.org/ntsb/DEN99LA146.md): Piper PA-32-260 · Aspen, CO · Accident · Minor injuries · Limited investigation · Final report · Aug 16, 1999 · N991RC · Destroyed
  > The pilot's inadequate in flight planning. Factors were the high density altitude, the lack of suitable terrain for a forced landing, and the sign post that the right wing impacted.
- [NTSB DEN99LA058](https://openairdocs.org/ntsb/DEN99LA058.md): Robinson R22 Beta · Englewood, CO · Accident · No injuries · Limited investigation · Final report · Mar 25, 1999 · N8354Z · Substantial damage
  > The flight instructor allowed the rotor rpm to decay during an autorotation which resulted in a hard landing.
- [NTSB DEN93FA054](https://openairdocs.org/ntsb/DEN93FA054.md): Witts & Church Worloch · Lucerne, CO · Accident · 1 fatal · Field investigation · Final report · May 6, 1993 · N3201K · Destroyed
  > Loss of control in flight. A factor was: the pilot's lack of experience in the airplane.
- [NTSB DEN86LA037](https://openairdocs.org/ntsb/DEN86LA037.md): Grumman AA-5A · Fort Collins, CO · Accident · No injuries · Limited investigation · Final report · Dec 1, 1985 · N991OU · Substantial damage
  > The plt stated that during takeoff roll the acft used over twice the normal distance to rwy to become airborne. After becoming airborne, the stall warning sounded, and continued to sound until the forced landing when the plt said he couldnot maintain alt. The…
- [NTSB DEN85LA078](https://openairdocs.org/ntsb/DEN85LA078.md): Raven S55A · Littleton, CO · Accident · No injuries · Limited investigation · Final report · Jan 13, 1985 · N81DS · Substantial damage
  > The balloon envelope collided with power lines after dragging the basket & occupants aprx 200 yards along an open fld and through a fence which damaged the basket containing the occupants. The balloon plt said that the wind was only 5 KTS at takeoff but after…
- [NTSB DEN76FTE70](https://openairdocs.org/ntsb/DEN76FTE70.md): Hughes 269B · Broomfield, CO · Accident · No injuries · Closed · May 18, 1976 · N9440F · Substantial damage
- [NTSB DEN76FTE18](https://openairdocs.org/ntsb/DEN76FTE18.md): Bell 47G3B1 · Denver, CO · Accident · No injuries · Closed · Aug 24, 1975 · N90769 · Substantial damage
- [NTSB DEN71FTE66](https://openairdocs.org/ntsb/DEN71FTE66.md): Piper PA-24 · Sugar City, CO · Accident · Serious injuries · Closed · Apr 4, 1971 · N5418P · Substantial damage
- [NTSB DEN70AD044](https://openairdocs.org/ntsb/DEN70AD044.md): Hiller Acft FH1100 · Blanca, CO · Accident · No injuries · Closed · Jan 8, 1970 · N390P · Substantial damage
- [NTSB DEN69A0048](https://openairdocs.org/ntsb/DEN69A0048.md): Beech 35-33 · Del Norte, CO · Accident · 7 fatal · Closed · May 6, 1969 · N2737T · Destroyed

## 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."eventStateOrRegion" = 'CO' AND c."eventCountry" = 'USA'
  AND c."mKey" IN (SELECT case_mkey FROM case_phases WHERE main = 600)
ORDER BY c."eventDate" DESC, c."ntsbNumber" DESC
```

This list as a web page: https://openairdocs.org/ntsb-phases/600/cases?state=CO

---
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.