In article ,
, son_of_flubber says...

On Monday, April 20, 2015 at 1:55:12 PM UTC-4, wrote:
why not have one of these:

http://store-vllhq23n.mybigcommerce....-in-enclosure/
http://store-vllhq23n.mybigcommerce....dback-systems/

'Wings level upright' and 'wings level inverted' gives the same reading on this instrument.

But a different reading on the pilot

--
Duncan.