On January 2, 2026, at about 1100 mountain standard time, an MD Helicopters MD369FF helicopter, N3502P, was substantially damaged when it impacted a highline/slackline near Superior, Arizona. The pilot and three passengers were fatally injured. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. Slacklining is a sport where a participant balances on a 1 to 3 inch wide piece of webbing made from synthetic fiber that is suspended between two fixed points. A subset of the sport, called highlining, entails rigging the slackline at higher altitudes above terrain, and often involves longer slacklines. Typically, a highline/slackline consists of a mainline that the participant balances on, and a backup line that the participant connects their safety harness to. The mainline is tensioned between two anchors, and the backup line is loosely attached to the mainline with intermittent connectors. According to a witness, on or around December 26, 2025, he and a group of friends traveled to the area near the accident site, which consisted of a valley with terrain elevations that ranged between 2,600-3,500 ft mean sea level (msl). Using two anchors spaced on bluffs about 0.74 mile apart, they raised a signalization line that carried five windsocks and about ten LED lights. After the signalization line was raised, they used additional nylon lines to draw the mainline and backup lines between the anchors. (See Figure 1.) The lines were oriented in a generally north/south direction and were estimated to be about 600 ft above the ground at their highest point. Figure 1: The series of lines between the anchors, as viewed from the northern bluff (photo courtesy of witnesses). On or about December 30, 2025, high winds and rain were predicted near the accident site, and the slackliners chose to lower the mainline and backup line. On the morning of the accident, the weather had improved, and the slackliners began to draw the mainline and backup line from the northern anchor toward the southern anchor. According to one of the slackliners, who was standing near the southern anchor point, the mainline and backup line had been drawn partway between the anchors when he heard the helicopter approach. The witness turned to the south and saw the helicopter flying at about eye level in an easterly direction. The helicopter briefly disappeared behind nearby terrain, and when it reappeared in the witness’s line of sight, it was flying toward the set of lines suspended between the anchors. The witness reported that the helicopter impacted the lines and appeared to slow or even reverse direction. The helicopter pitched nose up and yawed to the right, after which its tailboom separated. The fuselage became inverted, and the tailboom and fuselage subsequently impacted terrain about 150 and 350 ft from the lines. (See Figure 2.) Figure 2: The helicopter fuselage. The northern bluff, signalization line, and sections of the highline/slackline are visible in the background. According to first responders, about an hour after the accident, a second helicopter flying a similar flight path flew about 10 ft under the signalization line, which had remained suspended after the accident along with portions of the highline/slackline webbing. Examination of the helicopter revealed material consistent in appearance to highline/slackline webbing imbedded in the upper part of the vertical stabilizer. (See Figure 3.) The lower ends of the horizontal stabilizer end caps were sheared off, and striations similar to the webbing weave pattern were visible on the paint on the vertical and horizontal stabilizers. Additional striations were found on two of the main rotor blades. The helicopter was equipped with a wire strike protection system that consisted of cutters on the top and bottom of the forward fuselage. The cutting surfaces did not show any striations or disturbed paint. Figure 3: Highline/slackline webbing imbedded in the vertical stabilizer. On December 21, 2025, a Notice to Airmen (NOTAM) was filed by a friend of the slackliners that showed the presence of a “tight rope” about 3 nautical miles south of Superior Municipal Airport (E81), Superior, Arizona. The NOTAM was active between December 26, 2025, and January 6, 2026. The wreckage and sections of the highline/slackline were retained for further examination.