I’m sure we’ve discussed this backup A-EFIS before, so apologies for any duplication. Requirements for both iOS and Android devices are: 3-axes gyroscope, a 3-axes accelerometer, a 3-axes magnetometer and a GPS receiver. Would an iPad2 and/or iPhone 4S have these features? I assume it would be ‘assisted GPS’, though the definition of ‘assisted GPS’ is hazy...