The most interesting statement to come from this debate is JimLs explanation of the lack of visual cues avaiable to the pilot during landing - and as he explains, that spawned the necessity of the HAPs model.
In effect this statement (if true, and with a bit of offshore experience myself I think it is) pretty much kills any attempt to adopt a predictive performance environment for offshore.
Therefore, is it right to even attempt to define and control the many variables in play and of course the answer will always be YES, otherwise progress would never happen.
Having said this I am with Geoffers on this one. The environment we operate in offshore is dynamic, often unstable and always demanding. To even imagione how crews would fare when faced with the potential of complex computations, that due to the variables at any one minute changing, are probably inappropriate and flawed is one thing. To consider the chaos caused to the transport system (which is what we are part off) is unimaginable.
Some things in life get invented early on and they are pretty darn perfect. The wheel being one of them that springs to mind.
In my opinion, the work done all those years ago to define the HAPs modelling, and the slight adjustment by JAR to give a bit of thrust margin (AEO HOGE), is the "wheel" of the offshore environment.
I am somewhat dissapointed that so much effort has been expended into this issue and so little effort expended to tidy up and improve on what we have now. In my experience, majority of Offshore CPs occur way to low. Typically about 20 to 25 feet, and some significantly lower than that.
And yet the HAPs wants us at 40 feet ADH (I figure I noticed entirely lacking in JimLs disitations above (sorry JimL - sure this was just an oversight).
I challenge every Offshore pilot to look closely at their own personal CP profile. For the avoidance of doubt, and in concurrence with JimLs early posts, HAPs says we should have:
10 Knots G/S, rotor tips coincident with the deck edge, 40 feet ADH at the CP.
That is the equivelent of the 5 story block of flats above the deck.
For those of you who are too low, try the HAPs profile properly and you will be amazed at how much better the profile feels.
Geoffers is absolutley right in my opinion. The proposal is not only too complex, it is probably ill conceived from the outset.
Finnaly. in all of this little discussion has been made as to the mitigation of exposure (when it exists). Remember that JAR 3.517 carried a significant burden for the Operator and the Aircraft to reduce the possibilities of OEI by mandated use of HUMS, Reliability, training and of course profiles utilised to reduce the risks of Exposure in so far as is possible in the environment (the HAPs model).
The apparent lack of in service OEI events in the landing and take-off phase bears testiment not only to the helicopters inherent reliability, but the value of these mitiogation tools.
It is never a good thing to resist change solely due to the inertia of current practice. But In this instance that is where I am at unless someone can greatly simplfy the mindboggling data splurged throughout this thread.
DB