Part 107 UAS pilot reported programming the RTH altitude during pre-flight to remain within the LAANC approved altitude. During the RTH the UAS briefly climbed into controlled airspace and the UAS pilot caught the error and manually descended.

Narrative

Drone mapping operations were being conducted In Accordance With (IAW) part 107 operations; under Class D airspace (HEF). Operations were authorized under 200 feet AGL to avoid Class D airspace due to the close proximity to Manassas Regional Airport. During an RTH (Return-to-Home) maneuver; at the end of the mapping cycle; the pre-programmed RTH altitude was 195 feet. However; the drone climbed to 225 feet into the Class D airspace before the remote PIC identified the incursion and manually reduce the altitude to exit Class D airspace. This was a momentary incursion and no aircraft were visible nor affected during the flight into Class D airspace.After the drone landed; a complete review of the remote settings was accomplished. It was confirmed all altitudes and settings were appropriate for the mission; as planned. There is/was not obvious reason for this Drone to increase altitude above the 195 feet programmed RTH altitude. This altitude deviation was inadvertent; identified quickly and remedied. Safety was not compromised. However; it remains an issue that the Drone will unknowingly deviate from norms and programed parameters.