0324 GMT October 22, 2020
The report, which was prepared by Michael Gilmore, the Pentagon’s director of operational test and evaluation, raises serious questions about whether the US military should risk committing itself to buying billions of dollars of the F-35s before they have demonstrated they are fit for combat.
The fifth-generation stealth warplanes, which are being built in three different versions by Lockheed Martin Corp, will form the backbone of the military's future fighter fleet.
In the latest blow to the program, engineers uncovered numerous technical problems during extensive testing of the newest versions of the F-35, the Pentagon report found, adding to a list of issues including software bugs, technical glitches and cost overruns.
“Unless remedied, these deficiencies will translate into significant limitations for the F-35 in combat against existing threats,” the report said.
The report also found that the F-35's ejection seats could kill pilots who weighed less than 136 pounds (62 kg).
"Testing showed that the ejection seat rotates backwards after ejection. This results in the pilot's neck becoming extended, as the head moves behind the shoulders in a 'chin up' position," the report states.
Pentagon officials have acknowledged that a decision at the outset to start building the fighter jet before testing was finished has caused difficulties, including repeated repairs, redesign work, slowing down production and raising costs.
The F-35 is the highest costing weapon in history, with a fleet of over 2400 units planned to be manufactured with an estimated overall cost of $1.3 trillion.
The Pentagon plans to purchase a total of 2,443 F-35 aircraft.
Nine other countries, including Britain, Canada, Italy and Turkey are helping pay for the jet's development and are buying hundreds of the jets.