The phrase "major instance" is correct and usable in written English.
It can be used to refer to a significant or notable occurrence of something.
Example: "The major instance of fraud in the company led to a complete overhaul of the financial department."
Alternatives: "significant case" or "notable example."
The case represents a major instance of money laundering that involves Iraq, Treasury Department officials said.
The movie was the first major instance in America of censorship under the Hays Code, which cracked down on racy Hollywood fare.
There was, it is true, one major instance of violence in the Confederation years: Shays Rebellionn in western Massachusetts in late 1786 and early 1787.
AARP's involvement in ALEC is the second major instance this year in which it provoked the ire of progressive groups. .
"This is such a major instance of the fall of John McCain, of what has happened to him.
If there has been one clear, repeatable pattern throughout American history, it is that any major instance of African American advancement has always been met with a massive white backlash.
By focusing on the managers who run hedge funds, the system has so far avoided any major instances of fraud.
The first major instances of rightwing populism would come in the 1930s – from the Catholic priest and radio host Father Charles Coughlin – and then, in the 1960s, with George Wallace's presidential campaigns.
The material in the section constitutes some major instances very abstract approaches to information structure.
The geologic structures documented in Colorado, New Mexico, and Utah coal mines were commonly associated with major instances of ground failure.
In this distorted type of Triple Helix, two major instances and sectors of activities are absent and repressed: first, research, innovation, and education activities; secondly, French civil society.
