WR - we have been here before. The problem is the awful statistical analysis that has been done on data that was awfully unprofessionally collected in the first place. These people need to go to college, on an elementary stats course.
But, let's have a go...
Does anyone have a URL to the latest busts survey? I read one a few months ago. I have just done a quick google and found a 2003/5 one
http://www.caa.co.uk/docs/33/CAPAP2003_5.pdf
which appears to be amazingly similar to the one I read.
The first thing that hits you is on page 12 (page 19 of the PDF) - 40.6% used a "GPS", 17.6% used a "moving map".
What the hell is this supposed to mean? It means either the report was written by somebody who doesn't know what a GPS is, or 40.6% of the pilots used a non-moving map GPS (the kind you buy at Milletts, alongside your £25 tent and a £20 sleeping bag) which is truly awful since these give you little or no situational awareness.
To me, 17.6% of pilots using a moving map GPS sounds very low, given that the bulk of busts were done by pilots with 100-499 hours. These are not novices, especially given that perhaps 90% to 95% of PPL holders never ever make 100hrs. These are pilots who are hanging in there for the long term. I can't find data on pilot age or license age breakdown; if there was one, one could get an idea whether these are real old-timers or just more current pilots who have not been flying long but do a lot of hours. A pilot doing 200hrs/year all over the UK gets more exposure to the risk than one doing 10hrs/year locally.
On page 9 (16 of the PDF) it shows Stansted is the #1 place for busts. Why? On the chart, there is nothing about that airspace which is complicated or ambiguous. Also everybody knows that these airports are there somewhere. It just needs accurate nav especially if squeezing into the Luton/Stansted gap. Clearly, IMHO, plain old nav accuracy is the real issue here.
Anyway, one could take the whole thing to bits. Lots of categories of causes which don't really mean anything.
Curiously, on page 31, the report issues the stunning recommendation
CAA should issue training schools with a formal GPS initial training syllabus and issue course approval to FTOs
.
Hilariously, on page 29 it says
Poor database accuracy. This is either due to incorrect depiction or the absence of some CAS boundaries. American databases do not appear to cater for every UK airspace category. Moreover, the onus is on the pilot to maintain database currency by purchasing updates from the manufacturer. Manufacturers are reportedly reluctant to reveal detail of their updates, and no open forum exists to publicise any shortcomings. Formal CAA equipment and database compliance would eradicate these problems.
and what has the CAA done to make their charts available in electronic form, free or at a nominal cost, ready to be used on a moving map GPS without inflating its price by a few hundred quid? Nuffink! Their Head of Charts just tells you it's not the CAA's business to interfere with commercial providers (like Memory Map). The excuse is that Ordnance Survey charge so much for their data, but you don't need O/S data for an aviation chart.
The thing that is missing is a survey of pilots who did not infringe, and their navigation habits. Anybody who has done Stats 1 Part 1 would know this. Without such data, one cannot say anything about how different nav methods affect busts.
So you are right, WR, there is no data on correlation between nav methods and busts, but that's none has been collected.