Originally Posted by
APC225
And if IMC or night and the 30 minute battery is gone, gather up some iPhones on the plane and use the compass app's level to provide an artificial horizon to maintain wings level. Sits nicely on the frame around one of the instrument displays. Use one until the battery is low then the next one until you can see city lights.
https://goo.gl/images/ut37Da
Go to the 1:30 mark to see it,
https://youtu.be/V2AIfPBpgl0
Shows wings level in a coordinated turn.