The one "flyb" provided a link to looks like a good, cheap solution to your requirements. Alternatively, if you fly with a PDA or smart-phone, there are several apps that most likely provide what you need. Not sure if any alarm would be loud enough for you to hear, however. I do have 2-3 timers that might also be suitable, similar/identical to the 2 bottom units at https://us.vwr.com/store/product/598737/timers
If they still work, I can send you them and you keep the one you want FOC.