Teratorn Aircraft, Inc. TIERRA II accident near Chico, California, April 22, 1984
On April 22, 1984 at about 3:00 am local time, a Teratorn Aircraft, Inc. TIERRA II (ultralight), registered UNREG, was destroyed in an accident near Chico, California. It was a personal flight under ultralight rules (Part 103). 1 person was killed. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The NTSB has not yet published a probable cause for this accident. Investigations usually take one to two years; this page updates when the final report is released.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 22, 1984 · about 3:00 am local time
- Place
- Chico, California · map
- Type
- Accident
- Injuries
- 1 person was killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Teratorn Aircraft, Inc. TIERRA II
- Registration
- UNREG · no longer on the register · serial 3113HF2T
- Damage
- Destroyed
- Flight
- Personal flight · ultralight rules (Part 103)
The NTSB's narrative final · quoted from the NTSB record
THE ULTRALIGHT WAS BEING TEST FLOWN AFTER ALTERATIONS TO THE ACFT & ITS FLIGHT CONTROL SYSTEM. THE PLT PUT THE ACFT THROUGH SOME MANEUVERS AND DURING ONE OF THEM, DESCRIBED BY WITNESSES AS A CHANDELLE, THE ACFT NOSED DOWN & CRASHED INTOTHE GROUND. THE ACFT DOVE FROM ABOUT 300 FT AGL. INVESTIGATION REVEALED THAT AN ELEVATOR CONTROL SEAT HORN HAD FAILED & SEPARATED IN FLT. PARTS OF THIS FAILED PART WERE NOT FOUND IN THE WRECKAGE. THIS CONTROL PART HAD BEEN MODIFIED WITH MORE SPACING WASHERS THAN REQUIRED WHICH INCREASED ITS TORSIONAL LOADING. AFTER THIS FAILURE, THE PLT HAD NO CONTROL OVER THE ACFT ELEVATOR.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
Pilot
- Certificate: student
- Ratings: single-engine land
- Flight time: 187 hours in all; 24 in this make and model; 25 in the last 90 days; 7 in the last 30 days; 108 as pilot in command
- Medical certificate: Class 3 (expired)
- Seat: left
The aircraft
- Airframe total time: 56 hours
- Last inspection: inspection type not recorded, March 10, 1984; 1 hours since
- Maximum gross weight: 775 lb
- Seats: 2
- Landing gear: fixed
- Engine: Rotax 503 (piston); 0 hours total
The flight
- Flight plan: none
- Runway 0
Weather at the time
- Light: dusk
- Wind: from 310° at 7 knots
- Visibility: 50 statute miles
- Sky: clear
- Temperature: 72°F (22°C), dew point 45°F (7°C)
- Altimeter: 30.00 inHg
- Observation at 2:45 am from CIC, 10 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Other NTSB records under UNREG the same tail number, which may have belonged to a different aircraft at the time
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.