Our wonderful friend Alex Ploner came by last evening as we were updating the Oz Report and carrying on at the campground headquarters. We were all happy to see Alex and looking forward to a full Italian team contingent.

Alex has been reading the Oz Report and was interested to see Gerolf's comments on the altitude restrictions and penalties in the start circle, as well as his comments on weather and task setting. He felt that some of those comments were unfair and did not reflect what actually happened.

You might recall that Alex won the last day of the competition (the Italians were the hot team) but was then penalized for being too high when he passed the start circle. Alex has assured me (and I believe him) that he was not too high according to his Compeo display (barometric pressure altitude) and was in fact 30 meters below the required height. He said that he had been above the height limit (that is taken only at the start circle circumference at the start time) before the window opening time, but side slipped his way down to get under the limit. His IGC track log of GPS altitude showed him 100 meters above the required height limit.

You also might recall that twenty nine pilots were assessed penalty points on that day, so there must have been either wide spread cheating or widespread problems with this penalty system. Gerolf wrote:

I suppose some pilots just take the altitude limit without allowing for any margin of altitude error.

The margin of error is the issue in contention here. Alex (like many other pilots) is flying with a Compeo which only displays barometric altitude, not GPS altitude. He set his Compeo to display the (barometric) altitude on launch as provided by the meet organizer. He also checked the GPS altitude on launch, as you can with the Compeo (etc.) and found that the GPS altitude at launch was 20 meters higher.  The GPS altitude and the barometric pressure altitude will diverge once the pilot starts circling up over launch (as they are not likely to be flying in a standard atmosphere).

If you set up a bunch of GPSes on launch and wait for a while they will all read about the same altitude (depending on how many satellites their GPS engine can connect to and triangulate from). But when you are flying the altitude values can be off because you are changing altitude and it takes a while for the GPS to perform the required calculation to determine your current altitude. If you are racing to get down below the height limit, your GPS altitude may still be above your actual altitude.

So we have a number of sources for error especially if the pilot's instrument is only displaying barometric altitude and we don't have a very good handle on what the range of errors is and the meet organizers haven't been able to give pilots a good idea of what that range would be so that pilots can adjust their behavior accordingly. In this case the accumulated error level seemed to be 130 meters.

So given this lack of solid technical guidance it was perhaps a bit premature to introduce this method of keeping pilots out of the clouds in the start circle (or at least near the circumference at the time the window opens) in a category one competition (given that it had not been tried in any previous hang gliding competition).

This method will perhaps be trialed here at the pre-Worlds (which is a category 2 competition), although I expect some further discussion about it tomorrow when Alex shows up at the team leader briefing. We, the team leaders, discussed it yesterday and Gordon Rigg (he of the strong opinions and sometimes sarcastic delivery) among others was less than sympathetic to those of us who rely solely on an instrument that doesn't display GPS altitude (5030, 6030, Compeo, Compeo+).

Alex likewise felt that Gerolf's characterization of the meet director, the task committee, and the task calling given the weather forecast (which Alex said were excellent in their accuracy) was unfair and did not represent the true situation. Alex realizes that the meet director was not an experienced competition hang glider pilot, but that he was reasonable and open to suggestions about how the meet was run and how the tasks were called.

Alex felt that the tasks were canceled appropriately and even though pilot swere able to fly on one day after the task was cancelled, there were storms in all four directions around Emberger Alm, within 15 kilometers, so that a task (other than a fish bowl task) would not have been possible. Alex did say that he was happy that there was not the north wind at Greifenburg that we experienced at the last Worlds there, so the air was much less rough and pilots were happier to be flying in air that was a lot more fun.