I have flown and been trained by prob one of the only Capts to have a four engine failure on an BAE146. It then became a fave of his as a sim instructor. The AC will glide quite well and you'll achieve at least 2nm per 1000ft in still wind. So yes it's possible, even with high terrain to glide to the airfield. What you're failing to understand is, the aircraft could not see the airfield visually, it was on emergency AC and DC power, the power situation leaves the captain on sby instruments and no navigational indications. This is why the Capt was desperate for vectors to the runway. With vectors he could still fly a heading and speed. Obv without secondary or primary radar available the controller had no idea where the AC was.