Bellanca 8KCAB N2976R

Summary

On 24 April 1990 at about 18:50 local time, a Bellanca 8KCAB registered N2976R, operated by Gran-Aire, Inc., was involved in an accident near West Bend, Wisconsin, United States. 2 people were on board and 2 died. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

24 April 1990 at 18:50

Classification

Accident

Location

West Bend, Wisconsin, United States

Coordinates

43.4192, -88.1796

Aircraft

Bellanca 8KCAB

Registration

N2976R

Category

Airplane

Engines

1

Operator

Gran-Aire, Inc.

Operating rule

Part 91: General Aviation

Purpose of flight

Instructional

Phase of flight

Not recorded

Route

Milwaukee → Unknown

Aircraft damage

Destroyed

Weather

VMC

Light

Day

NTSB number

CHI90FA117

2 people died.

INFLIGHT FAILURE OF THE RIGHT WING STRUT-TO-SPAR ATTACHMENT FITTING DUE TO FATIGUE INITIATED BY IMPROPER WELDING TECHNIQUES INVOLVING INADEQUATE POST-WELD COOLING CONTROL.

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

Read the full NTSB narrative

THE RIGHT WING SEPARATED FROM THE AIRCRAFT DURING AN INSTRUCTIONAL AEROBATIC FLIGHT. METALLURGICAL EXAMINATION REVEALED THAT THE RIGHT WING'S LIFT STRUT-TO-WING SPAR ATTACHMENT FITTING HAD FAILED DUE TO FATIGUE PROGRESSION IN BOTH SIDE PLATES OF THE FITTING. THE INITIATION AREAS WERE IMMEDIATELY ADJACENT TO THE ENDS OF TWO WELDS. IN THE WELD HEAT AFFECTED ZONE, THE MICROSTRUCTURE TRANSITIONED FROM A SPHEROIDIZED PEARLITE REGION NEAR THE BASE METAL INTO A COARSE TEMPERED MARTENSITE REGION ADJACENT TO THE FUSION ZONE.

Quoted verbatim from the NTSB record.