What is ATC Calculator?
ATC Calculator is an iPhone app used in stage rally competition to calculate check-in times. It is used to add time values together.
Why would you want to do that?
In stage rally competition, between stages, teams transit between points along the route. These are called controls. Teams are given a certain number of minutes to travel between controls and much check in within the correct minute.
Why can't you just use a regular calculator?
Because there are 60 minutes in an hour and 24 hours in a day and because sometimes time is specified as some number of minutes and sometimes time is specified as hours and minutes.
What devices does ATC Calculator run on?
iPhone, iPod touch and iPad. A predecessor app called TimeCalc runs on Palm.
Does ATC Calculator run on iOS 9?
No. Apple appears to have made a change in iOS 9 that stops ATC Calculator from running on that version of their operating system.
How do you use it?
The app shows the result from the previous operation, the currently entered value and a keypad. It works like a regular numeric calculator. Enter one time value, press "+", enter a second time value, press "-" and you have an answer.
How would I use this during a rally?
You start the rally at the MTC Out control at, say, 9:18 and are given 50 minutes to get to ATC1. Enter '9:18', then press '+'. Enter '50', then press '='. You get 10:08 and that is your check-in time. If the rally is using FIA timing, press '+', then '3' (or whatever the number of minutes between checking in and starting the stage at the rally). Then press '+', then the RS time. Press '=' and you have the arrival time for ATC2. Continue this throughout the rally.
Will it work with the CARS timing system?
Yes. Enter the actual stage start time, then add the stage bogey time, then add the transit time and you will have the arrival time for the next stage.