DEN02LA103 · Adler SA-1
Adler SA-1 · Accident: loss of control in flight while maneuvering
From Rocky Mountain Metropolitan Airport (BJC) to Rocky Mountain Metropolitan Airport (BJC)
Event
- NTSB case
- DEN02LA103
- 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
- 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
Adler SA-1
- Aircraft type
- Adler SA-1
- Category
- Gyroplane
- 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
- N551SA
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Rocky Mountain Metropolitan Airport (BJC), Broomfield, COTo Rocky Mountain Metropolitan Airport (BJC)
- 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
- Maneuvering
- 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
- 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 › Rotor RPM, not maintained
- Rotor system, main rotor › Oscillation
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
Witnesses observed "a rotor or a wing" separate from the gyroplane, and the gyroplane then descended and impacted terrain. According to the deputy's report, a rotor blade was found about 150 feet north of the point of impact, and other debris was strewn to the southwest. The co-builder of the accident gyroplane, who was also a close friend of the pilot, contacted three gyroplane experts: the designer of the SA-1 Dominator and President of Rotor Flight Dynamics; a gyroplane aerodynamist; and the designer of another gyroplane. They examined the wreckage and compiled both a factual and analytical report. The following is based on the factual portion of the report. The separated rotor blade was bowed upward and had fractured about 2 feet from the tip. The fracture was consistent with positive overload. There was orange paint and primer transfer marks on the top and upper leading edge (the tail cone was painted orange). The attached rotor blade was also bent upward. The propeller blades exhibited no strike marks. The rotor head and hub bar were intact. The hub bar, normally bent 2.5 degrees upward, was bent approximately 10 degrees upward. The roll pillow blocks bore evidence of hammering and were mushroomed. The pitch stops were similarly damaged. In the analytical portion of the report, the necessity of maintaining blade loading at all times in order to maintain main rotor blade rotation was noted. The fracture on the separated main rotor blade was in "a purely upward bending moment which could only have occurred if the blade rpm had dramatically slowed...If totally unloaded, the blade rpm can deteriorate as fast as 120 rpm/sec." Normal rotor blade rpm is 320 to 400 rpm. If rotor blade rpm were allowed to drop, increasing the velocity of air moving through the rotor system, severe blade "flapping" would result as evidenced by the pounding and mushrooming of the roll pillow blocks and bending of the hub bar on the rotor head. A toxicological test revealed 2.024 (ug/mL, ug/g) paroxetine in the blood and liver. The drug is an antidepressant and contraindicated for flight. The pilot's personal physician prescribed the drug for the treatment of fibromyalgia, a condition manifested by muscle soreness. Adverse effects of the drug include drowsiness, muscle weakness, agitation, and tremors.
Probable cause
the pilot's failure to maintain main rotor rpm, resulting in blade flapping, subsequent blade contact with the airframe, and loss of control.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record DEN02LA103
- Event ID
- 20020920X05186
- Case number
- DEN02LA103
- 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: 772fb0ae270cce9343d5be7ec1039bc104e7c2b490457e63cdaf9f6c2ee4a487; retrieved 2026-09-20T19:52:31.560Z.