Narrative:

Aircraft X landed on the wrong surface; west of runway in the grass; parallel to the runway. The aircraft did not skid off runway; touched down in grass; and slowed to a manageable speed to be able to taxi across the runway and to parking without issue. It appeared no damage to signage or lights during landing rollout. When I saw the aircraft in the grass; I went for the crash phone as my controller in charge (controller in charge) was telling me to pull it and call it an alert 3. I reported the issue to dispatch as an alert 3 emergency; and explained what had happened with the aircraft. While speaking with dispatch; it became clear the pilot was still in control of the aircraft and was able to taxi without issue; my controller in charge had me downgrade to an alert 2 emergency. Dispatch attempted to get the remaining emergency information; such as souls on board; but I did not have the information yet and told them to standby while I attempted to get the information from the local controller. After a few seconds they told me emergency equipment is on the way and to call back if the situation changes. A few minutes later my controller in charge spoke with dispatch on the landline and told them emergency vehicles were not required so I did not call back on the crash phone.it is unknown what caused this issue. The sun may have been a factor with getting lined up directly on the runway. The runway appeared easy to distinguish from the tower but I don't know what the pilot saw to cause the wrong surface landing.

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Original NASA ASRS Text

Title: ASE Tower Controller reported than an aircraft landed in the grass parallel to the runway.

Narrative: Aircraft X landed on the wrong surface; west of runway in the grass; parallel to the runway. The aircraft did not skid off runway; touched down in grass; and slowed to a manageable speed to be able to taxi across the runway and to parking without issue. It appeared no damage to signage or lights during landing rollout. When I saw the aircraft in the grass; I went for the crash phone as my CIC (Controller in Charge) was telling me to pull it and call it an alert 3. I reported the issue to dispatch as an alert 3 emergency; and explained what had happened with the aircraft. While speaking with dispatch; it became clear the pilot was still in control of the aircraft and was able to taxi without issue; my CIC had me downgrade to an alert 2 emergency. Dispatch attempted to get the remaining emergency information; such as souls on board; but I did not have the information yet and told them to standby while I attempted to get the information from the local controller. After a few seconds they told me emergency equipment is on the way and to call back if the situation changes. A few minutes later my CIC spoke with dispatch on the landline and told them emergency vehicles were not required so I did not call back on the crash phone.It is unknown what caused this issue. The sun may have been a factor with getting lined up directly on the runway. The runway appeared easy to distinguish from the tower but I don't know what the pilot saw to cause the wrong surface landing.

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.