View Full Version : Auto hover limitations?
Hi, it would be interesting to share work methods and limitations with the autohover between different helicopters.
How precise is your doppler?
Any limitations with your RAD alt hold?
The S76 start to have limitations in bigger waves (collective warnings) with its RAD alt hold.
The doppler also have limitations with big swell (white water) and in "blank water".
What about the S92, AB 139, I think they are a different generation?
How is it on the Sea King?
Thanks
HeliComparator
2nd Mar 2010, 23:18
Doppler is the technology of the 1980s and before. Doppler is a pain because as you say, the water is either too rough or too smooth most of the time! And it usually doesn't like to be near a ship etc.
Modern aircraft with SAR modes don't use doppler (eg EC225) - instead its inertial with GPS (double GPS for redundancy). This makes the auto-hover rock steady and unaffected by sea state.
Radalt hold is generally fairly "soft" so it does not bounce up and down with the waves. EC have chosen to trigger "fly-up" mode when height is more than 30' below datum height, so if waves are greater than +-30' (ie 60') then it might have a problem, but that is a fairly wild sea. Bristow will be getting SAR EC225 into Norway in a few months, it will be interesting to see how well it works in reality.
HC
Geoffersincornwall
3rd Mar 2010, 00:28
As an ex SEA KING man I was prepared to be disappointed by a system based solely on 'on-board' position/inertial sensors and no doppler. I was wrong. The system is amazing. I admit that I haven't played with it in open water but it was rock-steady over the lake and the design of the man/machine interface exceptional. Far more intuitive than the old LVI and all the controls on the cyclic and collective. My compliments to the design team. The acid test will be how the front-line SAR-boys get on with it and as yet I have no feedback. Do you have Phase 5 yet? If so what do you think?
G. :ok:
Txs for the answers...yes its one thing what the FM says and another thing how it works in reallity, will be interesting to see how the 225 performance will be...sounds very good...
Anyone with hands on autohover experience in sea state 5 or above with the new "on-board' position/inertial sensors system"?
CHC UK SAR use both S92 and AB139 with auto hover (sar mode) right?