Date: 202012
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Light: Dusk
Aircraft: EMB ERJ 145 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
Aircraft component: Fuel System
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; First Officer
Reporter qualification: Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Human factors: Communication Breakdown; Training / Qualification
Second reporter function: Captain; Pilot Flying
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Fuel Issue
Detector: Person Flight Crew
When detected: Routine Inspection
Result: General Maintenance Action
Contributing factors: Aircraft; Procedure; Human Factors
Primary problem: Ambiguous

Narrative: While doing preflight walk around; I noticed the fueler was using the pressure refueling when they shouldn't have been because it was MEL'd. I approached her and let her know that she shouldn't have been using it because it was MEL'd. She was aware of the MEL because she was touching the sticker in the fueling panel as she was fueling. Her response to me was 'I'm almost done and it seems to be working fine.' I told her that it doesn't matter if it seemed to be working fine because we had to follow the MEL and she told me she was only 200 lbs. from being done. So I went and let the Captain know and he called Operations to report the fuel truck and called Maintenance to make sure we were okay to fly. Just before closing main cabin door we noticed someone open up the fuel panel again. He was in a white truck and an orange vest. When we got to ZZZ1 on the post flight walk around my Captain asked me to check and make sure the MEL placard was still there and that's when we saw it had been removed and I got a new placard from the Captain and placed it back in the refueling panel. Placed new placard for MEL.Emphasis on compliance of fuelers with SOPs.


Second narrative: First Officer came in after preflight and said [the] fueler had used pressure refueling port to fuel; she was almost done fueling by the time he saw and was able to say something. At this point the fueling panel was MEL'd with a placard on the panel. Called Maintenance to see if there was anything to do in regards to fuel or the panel and they said they didn't have time to clear the MEL; if we had the appropriate amount of gas we were good to go. I called Ops (Operations) to mention the fueler had used a panel that was MEL'd and shouldn't have; gave Ops the truck number. Just before closing the main cabin door; I noticed the fueling panel open and we saw a white pickup truck next to the aircraft as well as someone in an orange vest at the fueling port. The fueling panel was then closed; we departed without incident. Upon arriving in ZZZ1; I asked the First Officer to check the fueling panel on his post flight and he said the placard was gone. We replaced the placard and left the aircraft for our overnight. Post flight inspection revealed the placard was missing. Replaced the placard on the fuel panel. Emphasize Fuelers compliance with SOP's.


Synopsis: Air carrier flight crew reported that the aircraft fueler was using pressure refueling port although it was not useable due to an MEL.