HISTORY OF FLIGHTOn October 12, 2021, about 0930 central daylight time, an experimental, amateur-built Glastar airplane, N628RS, was destroyed when it was involved in an accident near Waukesha, Wisconsin. The pilot and passenger were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight. The airplane departed Lawrence J Timmerman Airport (MWC), Milwaukee, Wisconsin, about 0915, with an intended destination of Salina Regional Airport (SLN), Salina, Kansas. The pilot received clearance for a special visual flight rules (SVFR) departure with the restriction to maintain an altitude at or below 2,300 ft mean sea level (msl). During the approximate 10 minutes between the time the pilot established contact with air traffic control and the accident time, the pilot did not respond to several controller inquiries. At 0921, a controller provided headings to help the pilot remain clear of class D airspace. When asked if he could climb, the pilot replied that he could not climb higher. At 0926, the controller queried the pilot since radar showed the airplane in a climb. The pilot responded that they needed to climb and that they hoped to get above the clouds. At 0929, the controller asked if the pilot would be able to maintain VFR or if they needed to return; however, the pilot did not respond. Radar contact was lost about this time. Automatic Dependent Surveillance-Broadcast (ADS-B) data showed the airplane as it proceeded southwest before entering a left turn at 0927:25 from an altitude of about 2,600 ft msl and a groundspeed of 95 kts. By 0928:53, the airplane had turned toward the north-northwest. Four seconds later, the airplane began a descent which began at 256 ft/min and increased to 8,640 ft/min before track data was lost in the vicinity of the accident site. Figure 1. ADS-B Data Plots The airplane collided with a tree and terrain in a residential area. There were no injuries to persons on the ground. PERSONNEL INFORMATIONThe pilot held a private pilot certificate with a rating for airplane single-engine land. He did not hold an instrument rating. AIRCRAFT INFORMATIONThe airplane was equipped with a AVMAP ELP V with a A2 ADHARS module, which allowed for an electronic primary flight display that included attitude and directional information. In addition, the airplane was equipped with an autopilot system. An instructor who had flown with the accident pilot reported that the pilot was familiar with the use of the autopilot. The airplane’s maintenance logbooks were not located during the investigation. METEOROLOGICAL INFORMATIONMeteorological information revealed that a low-pressure system center, conducive to the formation of clouds and precipitation, was present in the immediate vicinity of the departure airport. At 0845, the MWC surface observation reported an overcast ceiling at 900 ft above ground level (agl) and 10 miles visibility. At 0845, the Waukesha County Airport (UES) surface observation noted an overcast ceiling at 400 ft agl and 2.5 miles visibility in mist. Forecasts indicated a probability of clouds from 1,200 ft msl (300 ft above ground level) through 12,000 ft msl. Weather satellite imagery for the accident site showed cloud tops near 7,000 ft msl. In addition, solid cloud coverage was shown over most of the state of Wisconsin. AIRMET Sierra forecast instrument flight rules conditions due to precipitation and mist for the area of the accident site. The pilot requested weather information from Leidos Flight Service about 0731 on the morning of the accident. A specialist provided all standard weather information for the proposed flight. A search of ForeFlight information indicated that the pilot did not request a ForeFlight weather briefing, but did enter several flight routes into the app. No weather imagery was viewed within the app. AIRPORT INFORMATIONThe airplane was equipped with a AVMAP ELP V with a A2 ADHARS module, which allowed for an electronic primary flight display that included attitude and directional information. In addition, the airplane was equipped with an autopilot system. An instructor who had flown with the accident pilot reported that the pilot was familiar with the use of the autopilot. The airplane’s maintenance logbooks were not located during the investigation. WRECKAGE AND IMPACT INFORMATIONFigure 2. Wreckage Plots The initial impact point was identified as a tree, after which the wreckage path continued 90 ft toward a slight ravine then up an embankment, generally following a 134° magnetic heading. Both wings separated from the fuselage and were found in the debris path near the ravine. The main wreckage, which comprised the fuselage and empennage, came to rest against trees. The engine separated and came to rest 58 ft past the main wreckage. The propeller was separated from the propeller flange and was found near the main wreckage. All major airplane components were accounted for at the accident site. The flight control cables were separated in multiple locations with evidence of tension overload. An examination of the airframe and engine did not reveal any preimpact anomalies.