Date: 201909
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Aircraft: B737-800
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
Airspace: Class B ZZZ
ATC / advisory: Ramp ZZZ
Reporter organization: Air Carrier
Reporter function: Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Situational Awareness; Distraction; Communication Breakdown
Second reporter function: First Officer
Anomaly: Conflict Ground Conflict; Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Vehicle
Detector: Person Ground Personnel
When detected: Aircraft In Service At Gate
Result: Aircraft Aircraft Damaged
Contributing factors: Company Policy; Human Factors; Airport
Primary problem: Human Factors

Narrative: Flight was operated without any incident or irregularity until the gate arrival at ZZZ. Taxi instructions were to enter the ramp at spot XX; join the blue line; and taxi to Gate XX.Approaching Gate XX; we saw that the ramp crew wasn't ready; so I stopped the aircraft on the blue line; set the parking brake; and waited. After a couple minutes; the ramp crew removed a baggage cart from the safety area; got into position (3 crew: 1 at each wing tip and the lead marshaller); and they all signaled a clear/thumbs up.We both surveyed the gate area and from my perspective; I believed it to be clear. I made the 90 degree turn from the blue line onto the center of the gate lead-in line. Again we had a clear signal from all ramp personnel; so I focused my attention on the marshaller; taxied as directed; and brought the jet into its parking spot. We set the brake; completed checklists; said goodbye to passengers and flight attendants; and headed off to our next flight.After arriving at our next jet; I was notified that during parking at Gate XX; the lower left scimitar had made contact with a fuel truck.We returned to the original gate to meet with [Chief Pilot]. We completed drug and alcohol testing.[Chief Pilot] received a ramp video of the incident which we reviewed. We also walked back onto the ramp to look closer at the area.After seeing the incident video and walking around the ramp area; it became clear that the fuel truck was out of position and inside the safety zone. The red safety line in that area makes several turns; which had been blocked by the truck itself; and they are intermixed into various diagonal yellow lines. The proper configuration of the lines wasn't obvious to me as I turned the jet. That; combined with the all-clear signal from the wing walker led me into believing that all was clear and safe. We both thought that we were operating safely and taking care to navigate the dangerous ramp. We stopped and waited for the rampers to move a baggage cart; get into position and signal us to proceed forward to our parking spot. We both surveyed to gate area; and both believed it to be clear.I observed the parked fuel truck; but from my perspective I thought it to be clear of the safety area. The wing walker was near the truck and gave me the clear signal. At the time; I was apparently confused by all the yellow lines on the ground; and the red line with its turns and angles next to the truck. I certainly would have stopped the jet had I been in doubt or instructed by the ramp crew.I will double down on verifying that the gate area is safe and clear.Even when you think a gate area is clear; it's not always.Ramp and service vehicles are parked everywhere. The gate areas are very congested; and markings can be confusing and/or obscured. When a vehicle is parked within an aircraft's safety zone it would be helpful if there was an obvious signal either on the vehicle or in the area while the vehicle is there. This is especially true; when the intrusion is 'just too close'. While a truck on the center line is obvious; one just a few inches over the line is not. Maybe a traffic cone; tethered to the truck; which is placed in the safety zone?Better training for ramp personnel; to include surveying the safety zone; closely examining anything that looks close; and looking at the wing tips and the area of movement.Even though I believed my jet clear of any obstruction; it wasn't; and I take responsibility for that. I will continue to improve my diligence for safe operation.


Second narrative: Upon arrival at Gate XX in ZZZ; we had contact between our left lower scimitar and a fuel truck. Neither the Captain nor I were aware of the incident until we were contacted by phone during preflight on the subsequent leg.ZZZ ops reassigned us to Gate XX upon arrival. We taxied in via spot XX and the blue line to Gate XX. We came to a stop adjacent to and with our nose 90 degrees to the parking spot while we waited for the ground crew to raise their wands. I made a 'stay seated' announcement to the passengers; and the Captain and I visually surveyed Gate XX and the surrounding area. There was the usual amount of surrounding equipment; including a fuel truck servicing an aircraft at Gate XX. Nothing stood out as unusual to either of us.With three sets of wands now raised; the Captain advanced the throttles; made the 90 degree turn; and proceeded in to the gate. I focused my primary scan ahead and to the right; with a peripheral scan to the left. I believe I verbalized my usual 'All clear right;' and we taxied into the gate as normal; with the marshaller providing normal signals all the way to aircraft stop. At no point did either of us see; hear; or sense anything to be amiss until we received the phone call. A few factors:There are a number of overlapping and potentially visually overwhelming features painted on the surface to the left of Gate XX. The yellow crosshatching of the fire lane and to the multiple zigzags of the circle of safety; in combination with the position of the fuel truck at the time; somehow seem to have failed to trigger any suspicion on our part.While the left wing walker was out of sight to me after we began our left 90 degree turn into the gate; at no point did the marshaller or either wing walker signal any issue.I do not believe any form of distraction or lack of vigilance was a primary cause here. Both of us were engaged and focused on the task at hand; free of superfluous conversation or attention elsewhere.Having made those points; I take responsibility as part of the flight crew for failing to see something was amiss with that fuel truck. I cannot say I wish I'd paid better attention to my instincts; because I never sensed anything was amiss.Having said that; I take responsibility as part of the flight crewI've made a resolution to spend a few hours this week reviewing all the documents and diagrams I can find covering airport markings; signs; and procedures. I'm also redoubling my attention to all movement on the ground; with particular attention to the sight picture of surrounding personnel; equipment; and markings on 'normal' days.The rest seems pretty obvious: the fueler should not park where he does not belong; and the wing walkers should signal a stop command if they see anything amiss.


Synopsis: B737 flight crew reported a failure of the ground crew to ensure adequate wingtip clearance; resulting in a collision with a fuel truck.