Gulfstream IV / G350 / G450
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 80; Flight Crew Total 6000; Flight Crew Type 1900
Communication Breakdown; Situational Awareness
Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Took Evasive Action
Airport; Human Factors
About 30 miles out we began listening to UNICOM at JYO on our 2nd radio. We heard one person in the pattern for 17 and an aircraft departing. We listened to the winds again and they were 040/4 kts. When we were about 20 miles out we asked the remaining aircraft in the pattern if we could switch the runway in use to 35 since the wind was out of the north. He said that was fine and after his next landing he taxied back to 35. There was another aircraft landing ahead of us. As we turned downwind for 35 they were turning base to final for 35. As we turned base an aircraft in the run-up block for 35 announced that an aircraft was departing 17 and not talking to anyone. We did not turn final. Instead we flew across the final at 1300 feet. We saw the aircraft and it started to turn our direction. We climbed to 1400 and then 1500 feet. The small aircraft never made a radio call and I do not think they saw us. We then entered overhead and left downwind to 35 again. We were watching for the other aircraft to see if they were going to remain in the pattern or depart. They departed and we landed without incident. I think the light wind contributed to this situation because the clam wind runway is 17. Winds were at 4 knots which a smaller aircraft might consider calm. I am thankful for the aircraft on the ground that discovered the bonanza taking off and made the announcement on UNICOM to us. Although it was clear; neither of us saw the small; brown aircraft until the aircraft on the ground announced it. I think a tower in this congested airspace/airport would be beneficial in preventing this situation in the future. Maybe if the other aircraft had done a radio check on UNICOM they might have noticed they were on the wrong frequency. I think we should have considered switching back over to Potomac and climbing back into the Bravo airspace more quickly.
Gulfstream IV Captain on a visual approach to Runway 35 at JYO; experiences an airborne conflict with a Bonanza departing Runway 17 without any announcements on UNICOM. Another pilot on the ground announced the departure; preventing a much closer conflict. The reporter believes that the Bonanza pilot was on the wrong frequency.