Date: 201507
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: Challenger 605
Operator: Fractional
Operating under: Part 135
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Ground ZZZ
Reporter organization: Fractional
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness
Second reporter function: Pilot Flying; Captain
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Aircraft
Detector: Person Ground Personnel
When detected: Routine Inspection
Result: Aircraft Aircraft Damaged; Flight Crew Became Reoriented; General Maintenance Action
Contributing factors: Aircraft; Human Factors
Primary problem: Human Factors

Narrative: We were taxiing out towards Z1 when we were advised to exit Z2 because a plane was being towed in on Z1. We made a left turn down one of the last lanes on the ramp to proceed to Z2. We taxied between 2 planes that were parked. I was looking out the right side to assure clearance and informed the captain; who was taxiing; that we had plenty of room. I assumed we cleared the left side as we continued to taxi. I felt a small bump as we taxied out; and assumed we had passed over one of the drainage grates on the ramp. Upon landing; as I opened the door; the lineman said something to the effect of 'you're missing part of the wing'. I looked up to see that the top of the winglet was indeed missing. I informed the captain of the problem and he proceeded to take pictures and call maintenance. Perhaps wing walkers in the ramp area until we are out of the ramp area and on to a taxiway.


Second narrative: The aircraft was parked in the first row facing the FBO building. We had been on a ground hold for departure and once we got a clearance to start engines; I performed the final walk round and closed the door. After engine start and after start checklist were accomplished we received taxi clearance. A ramp marshal guided us out of our parking spot and we proceeded toward Z1. As we approached Z1; ground redirected us to exit the ramp at Z2 due to an airliner being towed toward Z1. We made a left turn and taxied across the back row of the ramp toward Z2. There were two airplanes parked at the far end of the ramp; near Z2; one on parked to our left; and one on our right. There appeared to be ample spacing for us to pass easily between the parked aircraft. I slowed the taxi and we checked wing tips for clearance. I did steer slightly left of the first airplane; which was on our right. The PM; sitting in the right seat stated we had plenty on clearance; and also we were clear of that airplane. I was watching the left wing then; and steered slightly back to the right. I watched the left wing until I believed we were well clear of the airplane on our left. I stated; 'ok; we are clear on the left'. We felt a bump; and because I was sure we were clear of both airplanes believed I had rolled across a steel grated storm drain. I had veered slightly on the first portion of the taxi to go around two other grates in the ramp so this made sense to both of us. Since I had thought we were clear of the aircraft on the left; we never considered that we had hit it the parked aircraft.The flight was normal; with no anomalies noted on the airplane. After shutting down and opening the door on the ramp we discovered the damaged winglet and immediately notified the company. Misjudged wing clearance. Contacted dispatch for flight recovery. Sent pictures and called maintenance. Called and spoke with CL60 chief pilot. Wing walker would have prevented this. We didn't call for them because I incorrectly believed we had more than ample space to pass between parked aircraft.


Synopsis: CL605 flight crew experiences damage to the left winglet during taxi out from the FBO ramp. The damage is not detected at the time but reported by ground personnel at the arrival airport.