Sadly
Jonesyboy they do it because they can afford to be picky. I'm sure
PN will enlighten us as to the exact figures, but certainly scores, probably hundreds apply for every aircrew post.
All things being equal (which I know they never ever are) someone with a history of asthma may be (in their opinion) marginally more likely to have problems.
If they can fill the (decreasing
) number of slots with asthma-free people, then I'm afraid they will. I guess it's applying ALARP or "ten to the minus sixth" or whatever it currently is to the airworthiness of the crews......
Edited to add:
Jonesyboy, I've just seen your longer post on the subject in the Medical Forum. I'm afraid your ambitions for multi-engined flying will make no difference, the RAF effectively sets FJ potential as the entry standard, as that is the largest number of slots they have to fill.