EF-111 Sparkvark airplane modelGeneral Dynamics EF 111 airplane model. Development of the EF 111A Raven ["Spark Varks"] began in January 1975 when the Air Force contracted with Grumman Aerospace to modify two F 111As to serve as electronic warfare platforms. The F 111s high speed, long range, substantial payload and reasonable cost made it the ideal candidate to protect allied tactical forces against enemy radar defenses. The EF 111A provided protection by using a jamming orbit