I Need a simple and short python3 code that count secounds in a background process

I Need a simple and short python3 code that count secounds in a background
process

Im trying to make a text based flight simulator in python. But i cant
really find out how i can count secounds in python. I want a simple code
like for example ( Import Time ) then do (time.sleep(1)). I tryed to do
this:
for takeoff_time in range(0,16):
time.sleep(1)
then do:
while takeoff_time == (15):
break()
print ("Fly Crashed Before TakeOff ")
time.sleep(2)
os.system("cls")
main()
any ideas? ps: beginner.