Long range flights can be extremely critical for combat pilots. What makes these missions particularly uncomfortable is not only the complexity of the navigation but the lack of restrooms.
The use of urine collection devices called “piddle packs” in small cockpit compels the pilots to disrobe, adjust the ejection seat and distract them from handling the aircraft. A tricky procedure that can be extremely dangerous if lap belts get stuck on the control stick. As happened at least twice in the past causing the loss of two fighter planes (and the succesful ejection of the respective pilots).
Next generation “piddle packs” pump urine from a pilot’s underwear equipped with an inflatable cup and a hose to a sanitary collection bag so they don’t even have to unstrap when they have to go. A system that is particularly useful when wearing not only a flightsuit but also the anti-exposure suit designed for cold water survival.
A similar underwear system was produced in Russia for the Sukhoi Su-27 pilots and transferred to China along with the planes and a full set of pilot flight gear (including ZSH-7 helmets, helmet targeting device, flight suites etc.) when People Liberation Army Air Force (PLAAF) got the Russian Flankers before China started to manufacture its indigenous version of the plane (the Shenyang J-11A, that entered service in 1998).
The pictures (provided by a source who wishes to remain anonymous), show the Russian underwear delivered to the PLAAF. They should be self-explaining about how it is supposed to work (with the main difference being that the hose is connected to the plane and not to a bag), even if they give no hint of actual comfort…
Anyway, since the Chinese Air Force decided to use cheaper homemade flight gear (and long distance flights were seldom performed) this type of “piddle pack” has disappeared from PLAAF’s warehouse soon becoming a collectors’ item.