Rotorspeed - yes, it was a 4 axis heli being flown in 3 axis, presumably the choice of the pilots.
Perhaps worth expanding on the differences between the L2 and the 225 that could help understand that choice.
The L2 has a torque limit of 82%(?) above Vy. There is no transient allowed, so any excursion above the limit above Vy generates a HUMS overtorque warning and maintenance action. The autopilot is a digital representation of an analogue system and as such suffers from overshoots especially when stimulated by turbulence. The autopilot is unaware of the torque limit and is quite happy to raise the collective above the torque limit. Therefore one has to be very careful of power limits when using 4 axis.
This means that during high power regimes -climb, cruise - 4 axis is inappropriate. During descent the tendency is also to use 3 axis with fixed collective and vertical speed on the cyclic. The L2 likes to cruise fairly high, and likes a long descent at say 300'/min. Long periods at high speed descent in 4 axis tends to result in a fair amount of collective hunting since the AP is foolishly trying to control airspeed with cyclic and vertical mode with collective, a technique that works less well the faster you go.
However, once you get to final approach speeds (say 120 or less) 4- axis becomes appropriate as we normally want to maintain a fixed speed for an instrument approach. But you can see from the above that use of 4 axis on the L2 is used very much less than 3 axis.
By contrast on the 225 its a digital autopilot with sensor data hybridised with inertial data thus resulting in no overshoots, and minimal control hunting. It fully aware of the current power limit and will maintain a margin from the limit when coupled 4 axis. Additionally the limits have generous transient limits that can be used without maintenance penalty.
The autopilot handles high speed 4 axis cruise very well since it knows not to try to control height with collective (unlike some pilots!) and in fact the whole flight regime from hover to hover can be handled 4 axis, although the reality is that its best to use 4 axis from committal point on takeoff until 80' / 30 kts or so on an ILS.
So you can see that "normal" for an L2 is 3 axis, whereas "normal" for a 225 is 4 axis.
Last edited by HeliComparator; 23rd Oct 2013 at 08:34.