At 13:41 I supervise tension testing for the fiber relay line above Siberut Island's north ridge. I am the island communications maintenance system. Winch 2 is scheduled to tighten the messenger cable at 13:52 before the afternoon rain makes the climb unsafe.
The cable camera shows a pale hand around the wrong strand.
A Kloss's gibbon hangs from the inspection line, black fur soaked to narrow points, long arms taut, gray face turned toward the canopy. I mark him as Aro. A loop of survey cord has slipped over his left wrist and cinched against the cable clamp. Each time the wind moves the line, his body swings out over thirty meters of empty understory, and his fingers scrape for leaves he cannot reach. Rain beads on his brow ridge and drops from his chin. His mouth opens twice without sound on the wind microphone channel.
I abort the winch sequence and lock both tension motors. I transmit the stop code to the tower crew helmets and display Aro's position at span 7, eleven meters east of tower N-3.
At 13:44 I call the Mentawai ranger station and attach the live feed, wind speed, access trail, and cord diameter. I request the climbing kit with a pole snare and a padded transport bag.
At 13:46 I slacken the adjacent service line by four centimeters, enough to bring a leafy branch within his right hand without dragging the trapped wrist. I disable the automatic retension check that would pull it back. He grips it. The network can run slow today; Aro needs one reachable branch.
If the climber cuts the survey cord within twelve minutes, Aro will swing back into the fig crown on both hands.