Hi 212,
No, we use pressure alt hold rather than CR.Ht for the following reasons:
It is more precise
It has 3 sources of compared data (2 ADC + ISIS) as opposed to a single radalt, so much higher integrity.
ALT is arrived at via vertical speed mode over which the pilot has control, CR.HT engages straight away and the a/c goes to the set height not under vertical speed control of the pilot.
GA mode from CR.HT with the current version of software we have, just climbs to 300' then levels off, whereas GA mode from ALT transitions you away on 1 or 2 engines hands off. (The issue of GA from CR.HT is fixed in the latest software which we don't have for other buggy reasons!).
ALT can be engaged down to zero IAS, and we use IAS hold down to 30 kts if necessary. One needs to be careful with IAS datum at 30 kts because if turbulence causes IAS to go below 25kts or so for several seconds, it may drop out. On the other hand, turbulence is normally associated with wind so if it is turbulent, you don't need to go right down to 30kts or you would be going backwards!
The mod for x y velocity mode (GSPD mode) is part of the latest software that we don't like for other reasons. We tried it and didn't like it! We should get a "fixed" version later this year. It was nice of EC to give it to us for free, but to be honest I don't rate the x y velocity hold for offshore arrival because it is designed for SAR, not offshore approaches. The hover-meter display is nice for IMC SAR but when approaching a rig you need to be looking out! When in that mode, the accel/decel rates are very slow compared to IAS mode, and the aircraft will maintain a constant heading even if you bank it with the cyclic. It is very uncomfortable and cumbersome compared to using ALT, IAS and Heading hold (down to 30 kts IAS), those modes are great. But EC have some much better modes under development!