# NTSB SEA91LA098: Richard Cheney Teratorn Tierra II, N134TA, Morgan, UT, May 5, 1991

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: May 5, 1991, 12:50 local (18:50 UTC)
- Place: Morgan, UT
- Coordinates: 41.010482, -111.670722 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=41.0105&lon=-111.6707&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious
- Status: Completed, report February 8, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 41423
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA91LA098
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41423/pdf
- Page: https://openairdocs.org/ntsb/SEA91LA098

## Probable cause

THE INADVERTANT STALL AND THE PILOT'S STEEP BANKED TURN.  FACTORS RELATING TO THE ACCIDENT WERE THE PILOT'S LACK OF QUALIFICATION TO CONDUCT THE FLIGHT AND THE STRONG TAILWIND CONDITIONS.

## Sequence of events

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

- Loss of control - in flight, takeoff - initial climb
  - maneuver - excessive, pilot in command (cause)
  - qualification, pilot in command (contributing factor)
  - weather condition - tailwind (contributing factor)
  - stall - inadvertent, pilot in command (cause)
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

THE ACFT LIFTED OFF AFTER A SHORT TAKEOFF ROLL, CLIMBED TO ABOUT 200 FT AGL, AND THE PILOT INITIATED A STEEP DOWNWIND TURN IN STRONG WIND CONDITIONS.  THE ACFT STALLED, DESCENDED NOSE DOWN, AND IMPACTED TERRAIN. THE PILOT HELD AN EXPIRED STUDENT PILOT CERTIFICATE.

## Aircraft

- Registration: [N134TA](https://openairdocs.org/deregistered/N134TA-2011-03-10), registration cancelled 2011-03-10, S/N 9473 (OpenAirDocs)
- Reported make and model: RICHARD CHENEY TERATORN TIERRA II (TERATORN T)
- Registry model: [Cheney Richard W TERATORN TIERRA II](https://openairdocs.org/model/cheney-richard-w-teratorn-tierra-ii) (registry code 05676W3) (OpenAirDocs)
- Category: Ultralight, amateur-built
- Serial number: 9473
- Airframe hours: 135
- Engines: ROTAX 532 65 horsepower reciprocating
- Damage: Destroyed
- Flight: Personal, Part 91
- Operator: Edward R. Olson
- Registered owner: Edward R. Olson
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Annual, September 5, 1986, 72 hours before
- Departed: 42U, MORGAN, UT
- Airport: 42U, Morgan County

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 36; student; medical: class 3, expired

## Weather

- Conditions: Visual (VMC), Day
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: 64 °F, dew point -0 °F

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19910505014079A](https://openairdocs.org/incident/19910505014079A), May 5, 1991: Amtrte TIERRA2, Morgan, UT, Destroyed. First flight in type. Made steep low altitude turn after takeoff and stalled the homebuilt.

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.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.