Chancellor 414A / C414
Flight Crew Multiengine; Flight Crew Private; Flight Crew Instrument
Flight Crew Last 90 Days 10; Flight Crew Total 550; Flight Crew Type 150
Situational Awareness
Conflict NMAC; Deviation - Altitude Excursion From Assigned Altitude
Air Traffic Control Issued New Clearance; Flight Crew Took Evasive Action
Human Factors
During 17;000 feet cruise; my passenger noticed two white stationary lights off the right side of the aircraft (2 o'clock). Passenger pointed out the lights to me (Pilot) and I noticed they were slowly drifting apart from each other but staying in the same position. After about 5 seconds I could start to see what looked like a fuselage and realized it was another aircraft about to hit us. I immediately dove the aircraft and we witnessed the white (wing markers?) lights pass right over top of us. There were no other lights on the unknown aircraft aside from two incandescent looking white wingtip markers. It was too dark and we were between layers so I was unable to ascertain the type of aircraft or size as it passed right over top of us. I was also fixated on controlling our aircraft in the quick descent. The passenger and I estimated the other aircraft crossed us at about 200 feet above. I radioed ATC about the situation and informed them of our sudden altitude loss. ATC reported that nothing was on their scopes and cleared us down to 11;000 feet. During the descent; a check of the cabin pressure showed a 5 psi differential pressure. A follow up call to ATC reported nothing on their radar anywhere near us. Our strobes and Navigation lights were on at the time of the event. Upon landing I inspected my aircraft's wing tip lights and tail light and found them all to be in good working order.
The pilot of a multi-engine aircraft became aware of another aircraft in close proximity; and took evasive action. ATC was unaware of any traffic in the area; and was unable to identify any on radar.