On Boeing 717, BR715 engines, there is mechanical connection from reverser scoop structure to LVDT via cable. Cannot recall indication as i am not fully certified engineer for that a/c type, might be transit/deployed light on EFIS. Another proxy sensors (unlock?) are located on lock actuators and senses if locking tongues moves out from locked position. This aircraft have full scoop reversers, like old DC/MD-series.
These reversers are locked mechanically by lock tongues, two/scoop, and overcentering links on pivot point. Canīt remember anymore is hydraulic rams pressurized to stowe all the time when commanded stowe.
Incidents happens for this a/c when reverser deploys during flight, manufacturer made some modifications to overcome this problem.
Like all a/c systems, these gadgets needs lots of maintenance.
Last edited by Corrosion; 5th Sep 2017 at 12:38.