Why isn't the pilot wearing the latest HMD for combat exercise? we've seen j20 pilots wear them before. guess PLAAF still prefers HUD over HMD for reliability or robustness perhaps...
a. rumor suggested the Chinese HMD helmet is still too heavy in their assessment, so they probably looking for improvement model
b. unlike F-35, J-20 at this stage is mainly taking A2A role, HMD won't help too much on the perspective, a regular light weight helmet these days normally is capable to attachment the some eye ball traction or simple display assessories to improve aero combat, plus the regular HUD is good enough for most of the A2A missile launches