Evaluation of the Safe Flight Instrument Corporation Stall Warning System for the OV/1D Aircraft

An evaluation of the Safe Flight Instrument Corporation (SFIC) stall warning system for the OV-1D aircraft was conducted by the US Army Aviation Engineering Flight Activity (AEFA) to determine variation in stall warning margins from those observed in USAAEFA Project No. 84-13 resulting from changes in the SFIC stall warning system and aircraft configuration. Changes in aircraft configuration included incorporation of wing tip radar jammer antenna fairings (AN/ALQ-136(V)2), and modification of the right wing deice boot to accept the stall warning system lift transducer. Changes in the SFIC stall warning system included addition of a pendulous accelerometer and software changes to the lift computer, and replacement of the 700 Hertz (Hz) audio tone generator with a 400 Hz audio tone generator. The test aircraft was equipped with the Louvered Scarfed Shroud Suppressor (LSSS) and was flown with and without external aircraft mission/survivability equipment installed. The evaluation was conducted at Edwards Air Force Base, California between 26 October and 26 November 1985 and consisted of 23 flights totaling 40.5 flight hours (32.5 productive flight hours). The evaluation consisted of two phases during which dual and single-engine unaccelerated stalls, dual-engine accelerated stalls and evasive maneuvers were performed.