Beierle THUNDER GULL J UNREG

Summary

On 24 August 1991 at about 18:25 local time, a Beierle THUNDER GULL J registered UNREG, operated by Mark Beierle, was involved in an accident near Santa Margarita, California, United States. 2 people were on board and one was seriously injured, one had minor injuries. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

24 August 1991 at 18:25

Classification

Accident

Location

Santa Margarita, California, United States

Coordinates

35.3099, -120.2701

Aircraft

Beierle THUNDER GULL J

Registration

UNREG

Category

Ultralight

Engines

1

Operator

Mark Beierle

Operating rule

Part 91: General Aviation

Purpose of flight

Unknown

Phase of flight

Not recorded

Route

Santa Margarita → Unknown

Aircraft damage

Destroyed

Weather

VMC

Light

Day

NTSB number

LAX91LA375

1 person was seriously injured.

THE FAILURE OF THE WING SPAR WHEN THE DESIGN LIMITS OF THE AIRPLANE WAS EXCEEDED BY THE PILOT. CONTRIBUTING TO THE ACCIDENT WAS AN INADEQUATE AIRFRAME DESIGN AND AN ABRUPT MOVEMENT OF THE FLIGHT CONTROLS BY THE PILOT.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

THE CERTIFICATED PRIVATE PILOT AND A PASSENGER WERE CONDUCTING A FLIGHT TEST OF AN UNREGISTERED, HOMEBUILT AIRPLANE. THE AIRPLANE WAS BEING MARKETED AS AN ULTRALIGHT VEHICLE WITH AN EXCEPTION OF THE ULTRALIGHT REGULATIONS GRANTED TO THE EXPERIMENTAL AIRCRAFT ASSOCIATION. THE PILOT WAS PERFORMING AEROBATIC MANEUVERS WHILE THE PASSENGER WAS FILMING THE EVENT FROM THE REAR SEAT. DURING THE PULL-UP PORTION OF AN IMMELMAN MANEUVER, THE LEFT WING FAILED AND FOLDED UPWARDS. THE PILOT DEPLOYED A BALLISTIC PARACHUTE TO CONTROL THE AIRPLNE'S DESCENT. AS THE PARACHUTE DEPLOYED, IT BECAME ENTANGLED WITH THE ENGINE PROPELLER AND WAS DAMAGED AND ONLY PARTIALLY INFLATED. THE AIRPLANE DESCENDED AND STRUCK THE GROUND AT ABOUT 50 MPH. THE AIRPLANE AND PILOT DID NOT QUALIFY FOR THE CONDITIONS OF THE ULTRALIGHT REGULATION EXEMPTION, AND THE VEHICLE IS CONSIDERED TO BE AN AIRPLANE.

Quoted verbatim from the NTSB record.