CHI07LA205 · Harpster Hawk Aero Tandem
Harpster Hawk Aero Tandem · Accident: loss of engine power en route
From Moore County Airport (SOP) to an unrecorded destination
Event
- NTSB case
- CHI07LA205
- 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
Harpster Hawk Aero Tandem
- Aircraft type
- Harpster HAWK AERO TANDEM
- 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
- N4022P
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Moore County Airport (SOP), Southern Pines, NCTo 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
- En route · cruise
- 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 engine power
- 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
- Engine assembly, piston › Seized
- Pilot in command › Unsuitable terrain or takeoff/landing/taxi area, encountered
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The experimental amateur-built Hawk Aero Tandem airplane sustained substantial damage during an emergency landing following a loss of engine power during cruise. The pilot stated that he had lost engine power after restarting the engine twice. He impacted a mound with his nose landing gear. A witness saw liquid in the fuel tank when the airplane was disassembled. The airplane was powered by a Hirth 2706 fuel-injected engine. The Blue Max two cycle oil's recommended fuel and oil ratio was 100:1. An engine manual supplement noted that the recommended fuel and oil mixture was 90:1 for fuel injected engines. The pilot reported that he used a 100:1 fuel/oil ratio. A representative of the engine repair facility stated, "This engine experienced a piston seizure of the mag[neto] end piston. ... The PTO side piston is undamaged and from inspection of this cylinder it appears that possibly there was too lean of an oil mix in the fuel."
Probable cause
The loss of engine power during cruise due to the piston seizure for undetermined reasons and the unsuitable terrain the pilot encountered during the forced landing. A factor was the rising terrain of the mound that the airplane impacted.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CHI07LA205
- Event ID
- 20070711X00916
- Case number
- CHI07LA205
- 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: local date, investigation status, coordinates. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 2007-06-19.
- API snapshot SHA-256: 6f2b542d73e5852eec0ac39d91c9df2b5fd0cdab0553d61af2cd8ba4d7be9234; retrieved 2026-09-22T03:44:35.253Z.