Japan's fleet of F-35s reportedly made 7 emergency landings before crash

• Five of Japan Air Self-Defense Force's F-35 jets reportedly made seven emergency landings prior to a crash somewhere in the Pacific Ocean last week, according to the Japanese newspaper Mainichi Shimbun.
• The emergency landings occurred in flight tests between June 2017 and January 2019, The Mainichi reported, citing defense officials.
• The crashed F-35, which was assembled by Mitsubishi Heavy Industries in Nagoya, Japan, was reportedly diagnosed with cooling and navigation system problems in June 2017 and August 2018.
• Four of the five F-35s with problems were also assembled by Mitsubishi.
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Five of Japan Air Self-Defense Force's F-35 jets reportedly made seven emergency landings prior to a crash somewhere in the Pacific Ocean last week, the Ministry of Defense said, according to the Japanese newspaper Mainichi Shimbun.

Two of the emergency landings were related to the crashed F-35, but the Defense Ministry approved the aircraft to fly again. The emergency landings occurred in flight tests between June 2017 and January 2019, The Mainichi reported.

Among other issues, the F-35s reportedly had problems with the fuel and hydraulics systems. The diagnosed aircraft were were inspected and refitted with parts.

The crashed F-35, which was assembled by Mitsubishi Heavy Industries in Nagoya, Japan, was reportedly diagnosed with cooling and navigation system problems in June 2017 and August 2018, according to The Mainichi.

Read more: The US and Japan still can't find a missing F-35, and its 'secrets' may be in danger

Four of the five F-35s with problems were also assembled by Mitsubishi, while the fifth aircraft was reportedly assembled in the US. All of Japan's F-35s have been temporarily grounded.

The downed $126 million aircraft marked the first time an international ally has lost an F-35. Search-and-rescue teams were able to locate debris of the wreckage but the pilot is still missing.

The particular F-35 was the first one assembled in the Mitsubishi plant and was piloted by a veteran who had 3,200 hours of flying time, according to Defense News and Reuters. The pilot reportedly had 60 hours of flying time in the F-35.

Following the crash, the US and Japan have conducted an intensive search for the aircraft. The Lockheed Martin-developed, fifth-generation fighter boasts several technological and stealth features, which could provide rivaling nations like Russia or China valuable intelligence, if found.

"There is no price too high in this world for China and Russia to pay to get Japan's missing F-35," the Senate Foreign Relations Committee tweeted.