Narrative:

Aircraft X departed VFR and called me airborne for his IFR clearance. He filed a good route but I needed to amend his altitude from 10000 feet to 13000 feet for the MEA (minimum enroute altitude). He was filed ALS-V368. I cleared him as filed but amended his altitude to 13000 feet.I would pick him up on radar at the western edge of my airspace so I made sure to have him report level at 13000 feet. I also asked for a report passing wapre intersection but he said he couldn't find the fix so I thought maybe he was already past it. I then told him to report 35 miles southwest of ALS and I asked him for his current location so I knew where he was on V368. I think he reported 25 miles from ALS. I coordinated with the next sector and told them he would contact them at the boundary.the pilot reported level at 13000 and a couple minutes later he asked if that was a good altitude for his location. I informed him that the MEA on V368 was 13000 and it was a good altitude. The question concerned me so I verified he was on V368. He said negative we are direct dro VOR. Based off of his distance from ALS and the direction to dro I estimated he was right in a 15300 foot mia (minimum IFR altitude). I told him about the mia and gave him a low altitude alert. I got him on radar a minute or 2 later and he was right in the center of the 15300 foot mia. I asked him if he could provide his own terrain and obstruction avoidance through 15300 feet and climbed him to 16000 feet.I changed his route to direct dro direct gcn. I coordinated again with sector 36 and tried to quickly explain the situation. I then questioned the pilot about the confusion. He thought he filed direct dro and not the route I had in the system. He apologized and realized he made a mistake. It's just a good thing it was VFR.

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Original NASA ASRS Text

Title: ZDV Center Controller reported an aircraft was cleared 'as filed' yet it departed on a different route and was below the MIA.

Narrative: Aircraft X departed VFR and called me airborne for his IFR clearance. He filed a good route but I needed to amend his altitude from 10000 feet to 13000 feet for the MEA (Minimum Enroute Altitude). He was filed ALS-V368. I cleared him as filed but amended his altitude to 13000 feet.I would pick him up on radar at the western edge of my airspace so I made sure to have him report level at 13000 feet. I also asked for a report passing WAPRE intersection but he said he couldn't find the fix so I thought maybe he was already past it. I then told him to report 35 miles southwest of ALS and I asked him for his current location so I knew where he was on V368. I think he reported 25 miles from ALS. I coordinated with the next sector and told them he would contact them at the boundary.The pilot reported level at 13000 and a couple minutes later he asked if that was a good altitude for his location. I informed him that the MEA on V368 was 13000 and it was a good altitude. The question concerned me so I verified he was on V368. He said negative we are direct DRO VOR. Based off of his distance from ALS and the direction to DRO I estimated he was right in a 15300 foot MIA (Minimum IFR Altitude). I told him about the MIA and gave him a low altitude alert. I got him on radar a minute or 2 later and he was right in the center of the 15300 foot MIA. I asked him if he could provide his own terrain and obstruction avoidance through 15300 feet and climbed him to 16000 feet.I changed his route to direct DRO direct GCN. I coordinated again with sector 36 and tried to quickly explain the situation. I then questioned the pilot about the confusion. He thought he filed direct DRO and not the route I had in the system. He apologized and realized he made a mistake. It's just a good thing it was VFR.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.