# NTSB LAX84FU026: Teratorn Tierra II, Chico, CA, April 22, 1984

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Final report
- Date: April 21, 1984, 19:00 local (Apr 22, 1984, 03:00 UTC)
- Place: Chico, CA
- Coordinates: 39.459365, -121.930076 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=39.4594&lon=-121.9301&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 24015
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX84FU026
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/24015/pdf
- Page: https://openairdocs.org/ntsb/LAX84FU026

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Airframe/component/system failure/malfunction, maneuvering
  - maneuver - performed, pilot in command
  - flt control syst,elevator control - failure,total (cause)
  - maintenance,major alteration - improper, other maintenance personnel (cause)
  - flt control syst,elevator control - separation (contributing factor)
- Loss of control - in flight, maneuvering
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

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.

## Aircraft

- Registration: UNREG (not matched to a registry record)
- Reported make and model: Teratorn Aircraft, Inc. TIERRA II
- Category: Ultralight
- Serial number: 3113HF2T
- Airframe hours: 56
- Engines: ROTAX 503 50 horsepower reciprocating
- Damage: Destroyed
- Flight: Personal, Part 103
- Registered owner: Hawker Flying, Inc
- Last inspection: Unknown, March 10, 1984, 1 hours before

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 42; student; airplane ratings: single-engine land; medical: class 3, expired; seat: left; toxicology performed; flight hours: 187 total, 24 in this make and model, 108 as pilot in command, 25 in the last 90 days, 7 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Dusk
- Wind: 310° at 7 knots
- Visibility: 50 statute miles
- Lowest ceiling: none
- Temperature: 72 °F, dew point 45 °F
- Altimeter: 30.00 inHg
- Observed at: CIC, 10 nm away

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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