On June 18, 1994, at 0625 eastern daylight time, a Mexican registered Learjet 25D, XABBA, collided with the terrain during an instrument landing system (ILS) approach about 1/4 mile from the threshold of runway 1R at Dulles International Airport (IAD), Virginia. The certificated pilot; the certificated co-pilot; and all ten passengers received fatal injuries. The airplane was destroyed during the impact sequence. The airplane was being operated as a non-scheduled passenger charter flight by TAESA of Mexico City, Mexico, a 14 CFR 129 certificated carrier operating in the U. S. A. under the provisions of 14 CFR Part 91. The flight departed Mexico at 2315 hours, re-fueled and cleared U. S. Customs in New Orleans, Louisiana, and departed there at 0355 hours. Instrument meteorological conditions prevailed and an instrument flight rules flight plan was filed for the flight. The flight arrived in the Washington, DC area and executed an ILS approach to IAD. The flight crew executed a missed approach and was attempting a second ILS approach at the time of the crash. ADDITIONAL PERSONS(CONTINUED): MARK TAYLOR, GENERAL ELECTRIC AIRCRAFT ENGINES, 1000 WESTERN AVE., LYNN, MA 01910