ATC Calc Plus
ATC Calc Plus FAQ

What is ATC Calc Plus?
ATC Calc Plus 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.

How is it different from ATC Calculator/ATC Calc?
ATC Calc Plus is the same as ATC Calculator with an additional feature. ATC Calc Plus will display a countdown to the calculated arrival time. It maintains its own idea of current time, different from the iPhone's time, that can be sync'ed to rally time.

What devices does ATC Calc Plus run on?
iPhone, iPod touch and iPad.

Does ATC Calc Plus work on iOS 9?
No. Apple appears to have made a change in iOS 9 that stops it from working with that version of their operating system. A fix to this issue is under development.

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.

Will the iPhone and the intercom in the rally car get along?
Like most mobile/cell phones, the iPhone can cause noise in the intercom system in your rally car. You can avoid problems with this by making your intercom system more robust against electrical interference (e.g., install electrical chokes) or by running this app on an iPod touch instead of an iPhone. Putting the iPhone in Airplane mode may also help.

Will I be able to see the app in bright sunlight?
The iPhone display can be hard to read in bright sunlight. To mitigate this, the values that are displayed are intended to constrast with the background as much as possible (at the expense of a more aesthetically pleasing look). In testing, even when the iPhone launcher was barely readable, ATC Calc Plus' time values and buttons could be read.

Will the display be too bright in a dark rally car when competing after the sun has gone down?
Some drivers are bothered by bright illumination from the co-driver seat. Since the ATC Calc Plus display was designed to be readable in bright sunlight, it can appear bright in a dark rally car. The best way to deal with this is to change the brightness setting for the iPhone.

When adjusting the time, why does the adjusted and unadjusted time seem to occasionally jump?
When adjusting the time, the displayed "Adjusted Time" and "Unadjusted Time" seems to move left, then right occasionally. If you look closely, you will see that the value for tenths of a second will display two digits instead of one, when going from .9 to .0. This is the result of a bug in the Apple software for converting dates to strings. The time is correct. Only the displayed value is wrong. Since this does not cause a problem with using ATC Calc Plus (and makes it easily to notice the top of the second), we just live with the bug.