EC Beans
There are three elements to Cat A:
1. Mass. (WAT Curves).
2. Obstacle Environment (including significant turbulence and or heat pollution from turbine exhausts).
3. Use of appropriate profile.
When talking about operating standards then PC1, PC2 or PC3 should apply if you are talking about Euro-Ops. To operate to PC1 standards you first need a helicopter that is certified to CAT A. Then you need to apply the more comprehensive parameters for the obstacle environment (See JARs). The inability to predict the impact of turbulence and heat pollution has prevented the introduction of PC1 in the offshore environment. The existence of Cat A profiles for offshore (and the use thereof) does not imply that Cat A standards (which must be capable of accurate prediction) are possible. In the same way the use of a Cat A profile alone (without the other two elements being present) does not convey Cat A status on the operation.
The most important factor when operating PC1 VMC is the mass management. Undoubtedly the reduction of take off/landing mass is the most contentious part of Cat A/PC1 but it is the factor that most contributes to the safety of the operation. Of course mass reduction in line with the WAT means lower payloads and it is this aspect of general operations that many pilots are either ignorant of or are simply prevented from doing by commercial pressures.
Use of a recognised profile that has been practiced in the simulator with the rehearsal of engine failure scenarios is likely to produce he best outcome no matter what the mass and probably gives the best chance of stepping out of the wreckage in one piece so don't ditch the profile even though obstacle data is unavailable and you are over the WAT.
In one recent incident I came across the culprits took off 5% over the certified MGW and with the CG 20% behind the aft limit and they had no idea that this was the case. Such ignorance is unforgivable.
So to respond to the thread EC Beans - do you want Cat A obstacles or PC1 obstacles? Are you likely to operate IFR in or out of these sites? It's likely that a plan/photo of the sight from overhead with range rings is not going to cut it by itself. It's a bit more complicated. More accurate obstacle data will be required. All that said there is nothing preventing you from operating Day/VMC using the Cat A WAT and the CAT A profile. I may not be Kosher Cat A/PC1 but it will be a practical solution you can apply anywhere anytime.
If you are going to do the flight regardless then do it at Cat A WAT and with CAT A profile.
G.
