For concise summary, I read Japanese news articles.
Note: my comments in square brackets.
https://headlines.yahoo.co.jp/hl?a=2019 ... 4-mai-socihttps://www.jiji.com/jc/graphics?p=ve_s ... 0j-04-w360https://mainichi.jp/articles/20190610/k ... 40/096000c2019/06/10:
Accident F-35 trained with three other fighters.
19:25, altitude 9,600 m, when first round of training ended, pilot said "21 [callsign], two kills."
[He shot down two wingmen, or his two wingmen allowed themselves to be shot down by him.]
After one minute, ground control instructed him to descend, to avoid US military aircraft at 11,300 m, flying to Kadena AB, Okinawa Prefecture.
From altitude 9,600 m, he began to descend, and said "Hai [yes], ryoukai [understood]".
After 20 seconds, he descended 4,900 m [vertical distance], to altitude 4,700 m.
Very fast dive, above 900 km/h, and pilot probably had spatial disorientation.
19:26:15, ground control instructed him to turn left, and his final reply was "Hai, knock it off [stop training]."
This was after he turned left, and G-LOC chance was low.
After 15 seconds, he additional descended 4,400 m [vertical distance], above 1,100 km/h.
19:26:30, altitude 300 m, he disappeared from radars.
At blunt angle, he flew into ocean.
His voice was calm, did not evasive manoeuvre, and did not eject.
If mechanical trouble, chance was high that aircraft would decelerate while descending, but he descended at inappropriate supersonic speed.