Location-based apps running on iOS 11.0.x devices no longer support the use of simulated GPS information from external flight simulation sources. Specifically, iOS 11.0.x will restrict any GPS location information from external accessories that is more than 15km from your physical location (as determined by Wi-Fi approximation, internal GPS, or cell phone towers).
This restriction is in place anytime you have Wi-Fi or cellular enabled and are receiving an approximate location, and for 30 mins after you enter Airplane Mode.
There are several workarounds that restore the functionality if you are willing to operate in Airplane Mode.
This issue affects all flight instructors, flight schools, and training departments using Bad Elf's flight simulation kits (both Bluetooth GPS or 30-pin Dock Connector cables). This includes users of the Redbird Flight Simulations' Cygnus products launched in 2012.
When your iOS device is connected to a local Wi-Fi access point, or has Wi-Fi enabled, the own-ship position reported by CoreLocation or your EFB app will no longer work if it is more than 15km away from your physical position.
There are several workarounds that will allow you to continue using your flight simulation kit with EFB apps on your iOS device:
Workaround #1: Before starting your training session, perform the following steps to clear the cached Wi-Fi location information:
- Put your iOS device into Airplane Mode (Wi-Fi, Bluetooth, and Cellular OFF)
- Go to Settings.app > Privacy > Location Services and toggle Location Services OFF, then back ON.
- If needed, turn Bluetooth back ON to detect and connect to your Bad Elf GPS unit.
- Keep Wi-Fi turned OFF, otherwise it will override the NMEA feed again.
Workaround #2: Put your device into Airplane Mode (Wi-Fi, Bluetooth, and Cellular OFF) and wait 30 mins. Turn Bluetooth back ON if needed to connect to your Bad Elf GPS, but keep Wi-Fi and Cellular data disabled. Start your flight training session.
Workaround #3: Start your "flight" at a location within 15km of your physical location and keep your speed under 300kts. You will be able to keep Wi-Fi enabled during your training session.
This issue has been fixed in iOS 11.1 (released Oct 30, 2017). Users should upgrade from 11.0.x to 11.1 when possible.