Vizzy

You can also just use the wait untill block, so
wait untill: Alt AGL > 15000

Try
while true
Alt AGL < 15000

but with vizzy there is never an exact number, it is almost always a minuscule fraction. unless you use the “round” operator, it will round the fraction to the nearest whole number

instead of using the less than (<) symbol, use the greater than symbol (>)

Try the [While()] block without anything in the empty bubble and use [If(AGL>{whatever AGL the craft is at while grounded}) Then] followed by an [else if(AGL>15000) then] [Break]. The while loop will continue to run indefinitely once it's started, even with the (bubble) empty, but will only start during the specified conditions. The [if()then] block is the start of whatever process you want to do, everything after that is up to you. The [else if()then] is how you set where(or when) you want the code to stop repeating itself, and the [Break] block ends any any ongoing while loops(only if it's nested in that particular loop). Basically you want the while loop to break at a certain AGL, so just use [else if()then] with a [break], and any parts of code after that will also work just fine without weird interference