LEAR-SIEGLER HOLDING TO DIVEST AEROSPACE UNIT Forstmann Little and Co said Lear Siegler Holding Corp plans to divest its aerospace group subsidiary, comprised of the Defense Electronics Group and the Components Group. Divestitures had been expected since Lear-Siegler, a diversified conglomerate, was acquired last December in a 2.1- billion-dlr-leveraged buyout by the Wall Street firm of Forstmann Little. Lear's aerospace group revenues for fiscal 1987 are expected to be about 700 mln dlrs, said Forstmann. The Defense Electronics Group designs and manufactures weapons, management systems, flight control systems, remotely piloted vehicles and reference and navigation systems, mainly for military markets. The Defense Group subsidiaries are Astronics Corp, which is based in Santa Monica, Calif., and employs 1,076 people; Instrument and Avionic Systems Corp, based in Grand Rapids, Mich., and employs 3,479 people; International Corp, based in Stamford, Conn., and employs 266 people; and Development Sciences Corp, based in Ontario, Calif., and employs 237 people. The Components Group manufactures pumps, bearings, and other industrial components as well as nuclear control drive rod mechanisms and valves. The Group's subsidiaries include Power Equipment Corp, based in Cleveland, which employs 880 people; Energy Products Corp, based in Santa Ana, Calif., which employs 755 people; Romek Corp, based in Elyria, Ohio, which employs 262 people; and Transport Dynamics in Santa Ana, which employs 254 people. Overall, Lear's Aerospace Group's eight subsidiaries employs 7,200 people. Lear Siegler said it plans to retain Management Services Corp, engaged in aircraft maintenance modification for various Department of Defense agencies. Morgan Stanley and Co will act as financial advsiors for the group's divestitures. Last month, Lear Siegler said it planned to sell its Smith and Wesson handgun business, Starcraft Recreational Products Ltd, the Peerless truck trailer operations, and other units, as part of its restructuring plans. Lear apparently will retain its Piper Aircraft unit.