DEN05LA013 · Cessna 170A
Cessna 170A · Accident: partial loss of engine power (non-mechanical) on approach
From Sumers Airpark (GWS) to an unrecorded destination
Event
- NTSB case
- DEN05LA013
- 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
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- 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
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Cessna 170A
- Aircraft type
- Cessna 170
- 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
- N9176A
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Sumers Airpark (GWS), Glenwood Springs, COTo not recorded
- 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 91: General Aviation
- 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 · VFR pattern final
- 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
- Partial loss of engine power (non-mechanical)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Fuel system, carburetor › Ice
- Pilot in command › Carburetor heat, not used
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
Prior to the accident, the pilot had been flying for approximately 1 hour. He stated that he descended from approximately 8,500 feet msl at an engine power setting of 2,200 rpm, without carburetor heat. This descent lasted approximately 20 to 30 minutes as he flew from west to east, approximately 60 miles. The pilot entered the traffic pattern at approximately 7,000 feet msl. He applied carburetor heat, enrichened the mixture "somewhat", and reduced power to approximately 1,500 to 1,700 rpm, "prepatory for landing." The aviation routine weather report (METAR) reported the temperature as 34 degrees Fahrenheit (F) and the dewpoint as 31 degrees F. According to the carburetor icing chart, conditions were conducive for "serious icing at cruise power."According to the pilot, he was on final approach when he "decided [the] aircraft [was] too high" and added throttle to initiate a go-around. The engine did not respond to the application of throttle. The airplane impacted the roof of a townhouse, slid down and subsequently impacted the side of an adjacent townhouse causing substantial damage to the airplane.
Probable cause
the pilot's failure to use carburetor heat which resulted in the formation of carburetor ice and the loss of engine power. Related factors were conditions conducive for carburetor icing and the lack of suitable terrain for a forced landing.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record DEN05LA013
- Event ID
- 20041027X01699
- Case number
- DEN05LA013
- 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, coordinates. 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: a1397f8407aa909d10fba7c4359e353da5e16f6624b6291d95981fd9bdec4b78; retrieved 2026-09-21T09:11:43.104Z.