337979
The investigation concluded that the accident was probably the result of controlled flight into terrain : that is , an otherwise airworthy aircraft was unintentionally flown into terrain , with little or no awareness by the crew of the impending collision .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
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