Mercury Aircourier Service American AA-5B accident
American AA-5B · Accident: loss of control in flight while maneuvering
From 36U · Heber City, UT to Duchesne Municipal Airport (U69)
Event
- NTSB case
- DEN83LA082
- 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
- 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
- Visual Meteorological Cond
American AA-5B
- Aircraft type
- American AA-5
- 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
- N4520V
- Operator
- Mercury Aircourier Service
- Onboard fatalities
- Unknown
- Route
- From 36U · Heber City, UTTo Duchesne Municipal Airport (U69), DUSCHESNE, UT
- 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
- Maneuvering · turn to reverse direction
- 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
- Loss of control in flight
- Also codedOther events the NTSB coded in the sequence, such as a wire strike after a loss of power. Flight Findings uses them for its kinds of event. Glossary
- Stall
- 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
- Pilot in command › Airspeed, not maintained
- Pilot in command › In-flight planning/decision, delayed
- Pilot in command › Proper climb rate, not possible
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
AFTER TAKING OFF AT HEBER CITY, UT, THE PLT TURNED TO A 090 DEG HEADING & BEGAN A CLIMB WITH FULL THROTTLE, MIXTURE FULL RICH, 80 TO 90 KIAS & APRX 500 FPM RATE OF CLIMB. AT APRX 6500 FT MSL, HE ALTERED THE COURSE TO 110 TO 115 DEG TO PROVIDE BETTER TERRAIN CLEARANCE, OVER A SLIGHT VALLEY FORMED BY CREEK DRAINAGE. AT THAT POINT, THE CLEARANCE WAS REPORTEDLY ABOUT 1000 FT. AS THE CLIMB CONTINUED, THE PLT NOTICED THAT THE TERRAIN WAS GRADUALLY GETTING CLOSER. AS HE NEARED THE TOP, HE SUDDENLY REALIZED THAT THE ACFT MIGHT NOT BE ABLE TO MAKE IT OVER. A 180 DEG TURN WAS STARTED. HOWEVER, AS A LEFT BANK WAS ESTABLISHED FOR THE TURN, THE ACFT FELT MUSHY & STARTED TO LOSE ALT RAPIDLY. THE PLT ROLLED THE WINGS LEVEL & PULLED BACK ON THE YOKE WHEN GROUND CONTACT WAS POSSIBLE. HOWEVER, THE DESCENT CONTINUED & THE ACFT CRASHED ON A TREELESS, SNOW CVRD SLOPE AT 9300 FT. THE PLT SUGGESTED CARBON MONOXIDE MIGHT EXPLAIN HIS INDECISIVENESS, BUT AN EXAM OF THE ENG & EXHAUST SYS REVEALED NO PREIMPACT MALFUNCTION OR FAILURE.
Verbatim NTSB analysis from the NTSB dataset
Sources
NTSB record DEN83LA082
- Event ID
- 20001214X42409
- Case number
- DEN83LA082
- 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: 1253261a93b1f794554e0f648878ddb9b982b882abcd6df6e3329f08c8265818; retrieved 2026-09-18T21:00:44.924Z.