Just for the sake of showing off some of my useless knowledge this is problably a joke about the aircraft in question having some... reliability problems in service. (Like "it's finicky engine sometimes stopped working and it fell out of the sky" problems.)
@Izack It is kind of weird, the Ki-61 Hien, it may suffer from so much problems, yet I actually like by just how forgivable it is in IL-2 Sturmovik 1946. Sure, it lacked the emergency boost, but hell, it's one heck of a good plane. For me, I prefer the Ki-61-I-Hei. Them cannons make me snicker behind the seat of the Hien. Now, if only those bombers quit killing the engine...
Title: It is far more than "a cough" "I'm so asthmatic. I can't even shoot down the B-29..." Yeah, "asthmatic" is too soft to describe you. Of course, Extra Midboss Patchouli saying "Today, I feel good" was equipped with an air-cooled engine.