With such a complex subject it is often useful to remove a number of elements that are not germane to the discussion. One of these is the introduction of the alternative spend argument.
We took this discussion from the EC225 thread which was based on an offshore scenario; why? For the obvious reason that both types will logically follow their predecessors into the oil support market - particularly (as stated before) as most of the remaining large reserves of offshore oil are contained in ‘deep water’ regions (that this will be an Achilles heel for the AB139 with its relatively short legs will be something that AgustaWestland may have to address in the near future).
As Gomer has pointed out in one of his posts (without considering these deep water territories), at least one offshore domain is subject to a number of hazards that others are not; this includes but is not limited to: uncontrolled airspace; bad or no weather reporting; a lack of ATC coverage.
If it considered that the risk of accidents, resulting from one or more of the above, is beyond the safety target set by the State (supposing there is one) it should result in a requirement for mitigating procedures or equipment to reduce the exposure. Whilst several of these (may) require infrastructure spending, it is likely that existing programs will assist in the reduction of some of these hazards.
One hazard - a combination of one or more of the above - is controlled flight into water. After a particularly nasty accident in the UK, it became a requirement to fit a radio altimeter with AVAD on offshore helicopters. There have been several posts that have extolled the virtues of EGPWS - of which I am a great supporter. However, when operating offshore, it is quite clear where the level of the surface is, and fixed platforms are mapped and of limited physical dimensions. However, unlike most onshore areas, we do have a number of transient obstacles that can range up to 500ft in height. EGPWS will not know about these transient obstacles and will not be as effective as one solution that has been used in the North Sea for decades - the RADALT, AVAD and weather RADAR. The introduction of geostationary satellites and differential GPS using WAAS will improve the effectiveness of that equipment.
I submit that the existing solution is cheaper than, and just as effective as, the more expensive one (which would not be true for onshore CFIT). (It could also be argued that controlled flight into water is not the true reason for a number of the accidents seen, but a loss of control resulting from inappropriate but inadvertent entry into cloud.)
Similarly for congested but uncontrolled airspace (both VFR and IFR); airborne collision and avoidance systems (I hesitate to use the acronym ACAS as it brings to mind specific solutions) might provide the protection we need for what is in effect ‘free flight’ in offshore domains. If the provision of this solution also includes the reading of automatic weather stations (both by the onshore base and whilst flying offshore) it will bring added value to the solution. CAPSTONE appears to provide one such solution.
I would also contend that the provision of landing aids that have been produced for onshore runway use are also inappropriate as they will not have taken into account the fact that the go-around must miss the largest obstacle in the area - the rig that you are attempting to land on. Present ARAs using RADALT and airborne radar but improved with the use of differential GPS will continue to provide the best solution for offshore approaches.
Equally, the use of offshore alternates v return-to-land-base-fuel must be the result of addressing the combined problem of offshore weather and the lack of single-engine landing performance to a rig. If the oil company decides (and the Authority accepts) that a non-assured emergency landing onto a rig could (to some mathematically defined probability) result in a more serious and catastrophic event, ditching is the preferable option (once again with a clearly defined risk of escape and survival governed by probability and consequence).
The point that I am attempting to make is that all of these technologies and procedures mitigate specific hazards which have to be addressed in their own right - if they result in an unacceptable accident rate. What is not, and must not be advocated, is the introduction of an additional hazard to mitigate the cost of providing other solutions.
Let's continue with the discussion of the provision of appropriate performance standards.
Last edited by JimL; 15th August 2004 at 12:38.