I read it as he can do it anytime.
I agree, unless FFG flat out FAQ it then the reading heavily suggests that Bonearms ability can trigger from any source of ioning. Be that himself or any of his allies attacking or even a self ioning through the feedback array.
Anyway, had my first game with my Scum fleet, took Kath in the Firespray, Kavil in the Ywing and 2 Black Sun Soldiers in Headhunters. Game went very successfully in Scums favour. The opening joust was badly in my disadvantage at first, a cunning Awing maneuver left Kath dangerously exposed in the middle of the field and Kavil was ioning and double stressed via Horton running an ion turret and the 'stressbot,' leaving my poor Ywing to fly into an asteroid field.
Luckily, this insult must have riled one of my Black Suns and he scored a natural 3 crit attack on Horton and his combined fire with his wingmate and Kath took the Ywing out of the fight on the 2nd turn. For the next few turns, my Firespray and Headhunters dueled with the Rebel Awing (Arvel) and Bwing (Keyan) but nether side managed to do much damage thanks to some very lucky dodge rolling on both sides.
The game fell into my favour when in one turn I separated the 2 Rebel ships, leaving Arvel to fight with Kavil (who by this point had flushed out all of his stress and was back in the picture) while Kath and the Black Suns surrounded and destroyed Keyan through concentrated fire, although in his defense he did manage to pull Kath down to 4 health and destroy one of the Headhunters.
After that it was just a case of mopping up the final Awing. He flew well and managed to get Kavil down to 1 lonely hit point but finally a tactical block with the last Headhunter and range 1 shot out of Kath rear firing arc took him out of the picture.
A few thoughts at the end of the game
1. Auto-thrusters is bloody terrifying. The Rebel Awing was sporting it and although we weren't counting, we think it gave him an extra 3-4 shield points over the course of the game and really shut down Kavil.
2. Kath is quite hard to line up correctly, I like her ability but I haven't decided on the best method to fly her yet. That said, I got 2 five dice attacks in that game which were both very devastating.
3. Blaster Turret Kavil is easily shut down with stress, But if left alone he can be a real beast to deal with.
4. Although he didn't live long enough to really enjoy it, the new title for Ywings has potential to really bring them back.