# NTSB LAX94LA222: Hillberg EH-101, N10TE, Corona, CA, May 21, 1994 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 21, 1994, 16:30 local (23:30 UTC) - Place: Corona, CA - Location: 33.8753° N, 117.5664° W: Placed by OpenAirDocs: center of Corona, CA, within about 6 miles (OpenAirDocs) - Nearby events: https://openairdocs.org/map.md?lat=33.8753&lon=-117.5664&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report March 27, 1995 - Report: Approved by Office Director - NTSB case key (mKey): 28744 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX94LA222 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/28744/pdf - Page: https://openairdocs.org/ntsb/LAX94LA222 ## Probable cause the pilot's loss of control of the helicopter while hovering downwind. A lack of test-flight data to establish the aircraft's performance limitations was a factor in the accident. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - in flight, hover - compensation for wind conditions - inadequate, pilot in command (cause) - performance data - information insufficient, pilot in command (contributing factor) - In flight collision with terrain/water, descent - uncontrolled - terrain condition - soft ## Analysis THE PILOT/AIRCRAFT DESIGNER WAS HOVERING AN EXPERIMENTAL HELICOPTER ABOUT 15 FEET ABOVE THE GROUND WHILE IT WAS BEING PHOTOGRAPHED BY ANOTHER HELICOPTER. THE PILOT TURNED THE TAIL OF HIS AIRCRAFT INTO THE WIND AND IT BEGAN TO SETTLE IN ITS OWN ROTORWASH. THE PILOT WAS UNABLE TO CONTROL THE DESCENT AND THE HELICOPTER TOUCHED DOWN IN SOFT TERRAIN AND THEN ROLLED OVER. THE HELICOPTER HAD ACCUMULATED 5.6 HOURS OF TEST-FLIGHT TIME AND THE PERFORMANCE LIMITATIONS OF THE AIRCRAFT HAD NOT BEEN ESTABLISHED. ## Factual narrative On May 21, 1994, about 1630 hours Pacific daylight time, an experimental Hillberg EH-101 homebuilt helicopter, N10TE, crashed while maneuvering at the Corona Municiple Airport, Corona, California. The helicopter was being operated as a visual flight rules (VFR) local flight when the accident occurred. The helicopter, operated by the pilot, sustained substantial damage. The certificated commercial pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed. The flight originated at Corona about 1615 hours. The pilot reported that he was flying at 15 knots airspeed while being filmed by another helicopter. The pilot slowed the aircraft and turned the tail into the prevailing wind. The helicopter began to settle to the ground from about a 15 foot hover and the landing gear touched down in soft terrain. The right front portion of the landing gear skid dug into the ground and the helicopter rolled over onto its right side. The helicopter received damage to the main rotor blades, landing gear skids, and tail boom. The helicopter had accumulated 8.5 hours of operation on the ground and 5.6 hours of flight time. The pilot's total time in the aircraft is also 5.6 hours. ## Aircraft - Registration: [N10TE](https://openairdocs.org/deregistered/N10TE-2021-10-02), registration cancelled 2021-10-02, S/N .01, built 1993 (OpenAirDocs) - Reported make and model: HILLBERG EH-101 - Registry model: [Hillberg Don EH 1 01](https://openairdocs.org/model/hillberg-don-eh-1-01) (registry code 130018D) (OpenAirDocs) - Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs) - Category: Helicopter, amateur-built - Serial number: 01 - Airframe hours: 6 - Engines: GARRETT GTPC-36-55-C 145 horsepower turbo shaft - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Donald Hillberg - Registered owner: Donald G. Hillberg - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, May 20, 1994, 1 hours before - Departed: L66 - Destination: L66, CA - Airport: L66, Corona ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 34; commercial; medical: class 2, valid medical--no waivers/lim.; seat: center; flight hours: 1,337 total, 6 in this make and model, 1,337 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: 90° at 5 knots, gusting 15 - Visibility: 50 statute miles - Lowest ceiling: none - Temperature: 66 °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 19940521015779A](https://openairdocs.org/incident/19940521015779A), May 21, 1994: Corona, CA, Substantial damage. During low altitude hover turned helicopter tail into wind. Settled. Skid dug into soft ground. Copter rolled over. 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.