DEN99FA016 · Piper PA-31-350
Piper PA-31-350 · Accident: in flight collision with terrain/water on approach
From City of Colorado Springs Municipal Airport (COS) to Yampa Valley Airport (HDN)
Event
- NTSB case
- DEN99FA016
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 1 · all aircraft and ground
- Ground fatalities
- 0
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- Charter & commuter
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Instrument Meteorological Cond
Piper PA-31-350
- Aircraft type
- Piper PA-31
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N35533
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From City of Colorado Springs Municipal Airport (COS), COLORADO SPRGS, COTo Yampa Valley Airport (HDN), CO
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 135: Air Taxi & Commuter
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Approach · IFR initial approach
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- In flight collision with terrain/water
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Destroyed
Cause areas
- Pilot in command › Descent, premature
- Pilot in command › Procedures/directives, not followed
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The Part 135 cargo flight was approaching its destination on an IFR flight plan. The pilot had requested the ILS-DME approach to runway 10, but 2 minutes later, he changed his request to the VOR-B approach to runway 28. ARTCC cleared him for the approach to the non-towered airport. The pilot contacted the airport's Unicom, and requested that the ramp personnel be standing by with fuel and oxygen. The airplane was found 5.8 nm from the approach end of runway 28, at 7,900 feet. The approach minimums for the VOR-B was 7,900 feet, which the pilot could descend to at 8.7 nm. The VOR was located 285 degrees at 13.6 nm from the accident site, and the ILS-DME transmitter was located 285 degrees at 5.6 nm from the accident site. The airplane was equipped with a single DME display head, and it had a Nav 1/Nav 2 selector switch.
Probable cause
The pilot not following instrument procedures and subsequently descended to minimums prematurely. Factors were the mountainous terrain and the falling snow.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record DEN99FA016
- Event ID
- 20001211X11234
- Case number
- DEN99FA016
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 7286effea77f09b3983d9fca5fb10ec73149abe6252a2305ee95555c8ad8a250; retrieved 2026-09-18T13:20:28.824Z.