20260102000049A

On January 2, 2025, a helicopter was on a recreational flight through telegraph canyon near Superior, Arizona, when the helicopter struck a highline/slackline that was an approximate distance of 1 statute-mile stretched between two peaks of the canyon. The helicopter came to rest approximately 750 feet beyond the highline/slackline, on an approximate heading of heading 337 degrees magnetic. The fuselage came to rest on its right side, mostly inverted. The aft 1/3 of the tail boom was separated, with the metal on the left-hand side bending in and the metal on the right-hand side bent out consistent with a rotor blade strike. Tail boom and tail rotor detached with minimum damage to tail rotor blades. Damage to the top of the tail section with material consistent with the webbing of the highline/slackline around the top of the vertical stabilizer where the horizontal stabilizer mounts. One main rotor blade was found near the tail boom wreckage that was intact, bowed back approximately 5 inches at the tip and had splaying of the trailing edge near the root to about the halfway point down the blade. This blade had transfer markings consistent with the striations of the webbing from the highline/slackline material, found 2/3 of the way down the blade towards the blade tip, on the underside of the blade with a transfer marking indicating swiping of the webbing towards the tip of the blade. One main rotor blade was not completely detached. The trailing edge was separated, leaving just the leading edge wrapped around the main rotor hub clockwise viewed from the top, with one section of the blade found to the right of the flight path, adjacent to the fuselage wreckage and forward of the tail boom wreckage. The blade tip was found forward and slightly to the right of the fuselage wreckage. One main rotor blade was found to the right of the flight path, forward of the tail boom wreckage and adjacent to the fuselage wreckage, that was curved into the shape of an “s”, with semicircular damage consistent with the diameter of the skids. Two additional main rotor blades were found to the left of the flight path, forward of the tail boom wreckage, and adjacent to the fuselage wreckage in close proximity to each other. One blade had a positive curve down the entire blade. The other blade had a negative curve down the entire blade. Debris field is scattered in one approximate direction starting after the highline/slackline in the direction of which the aircraft came to rest. Ground scarring is consistent with a high angle and low velocity impact. 4 POB 4 fatal.

The group of people erecting the highline/slacklining had not notified the FAA of the obstruction their high/slackline created as required by 14 CFR 77.5 (a) and 77.11 (a). Ac 70/7460-1M obstruction marking and lighting requires this notification to be done using FAA form 7460-1, notice of proposed construction or alteration. The kilometer-long highline/slackline across telegraph canyon had a red light operable at night at either end at the attach points and had five orange cone shaped windsock type markers approximately 36-inch long, evenly spaced across the canyon. There is no standard making provided for highline/slacklines in ac 70/7460-1M, and the closest possibly applicable guidance would be for catenary wires with four unlighted markers would recommend 36-inch orange balls spaced equally along the wire at intervals of approximately 200 feet.

The group the erected the highline/slackline filed the following NOTAM: NOTAM#: 12/234 prc 12/234 E81 obst tight rope WI an area defined as 1NM radius of 331412N1110714W (3NM s E81) 2800FT (600FT AGL) flagged and lgtd 2512261400-2601060200.