The Intercept has put together a comprehensive article on the U.S. Navy EP-3E (BuNo 156511) collision with a Chinese J-8 fighter off Hainan island on Apr. 1, 2001.
By SDASM Archives (VP-30 LL-30 -2 WEB) [No restrictions or Public domain], via Wikimedia Commons
A comprehensive U.S. Navy-NSA report completed three months after the collision was leaked by Edward Snowden in 2013 and Kim Zetter also spoke to two crew members who were on board the spy plane at the time of the incident.
The Pentagon and intelligence community concluded that exposure of classified information were substantial but the losses were not catastrophic. Instead, they deemed the losses medium-to-low in severity.
Luck was on the American side, the aircraft was two weeks away from being upgraded with new equipment. Thus, many stuff on board were old, outdated and simply not working.
Hit the link below for the article.