Tricky double knife-edge gate prompts rule change in Windsor

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Tricky double knife-edge gate prompts rule change in Windsor

Tricky double knife-edge gate prompts rule change in Windsor

by Kirsten Corrigan, Jun 5, 2010

WINDSOR, Ontario – An important waiver was issued by the Race Committee after yesterday’s training flights in Windsor to allow for additional safety in the challenging track over the Detroit River, where winds and turbulence are influencing the race lines taken by the pilots.

The waiver came in the wake of a tense morning where Austrian pilot Hannes Arch dramatically suffered a wing stall, slicing a pylon and damaging his Edge 540. Despite the coincidental timing, the temporary rule change was already in motion and echoed the decision taken in Canada last year to waive a specific rule regarding the return to a wings level position after either a quadro or double knife-edge gate.

Under the current rules, (Section 8.1.3.1), pilots must, under usual circumstances, leave the knife-edge gates in a wings level position before manoeuvring for the next gate. Failure to do so is usually considered ‘Dangerous Flying’. Due to the current track design for Windsor 2010, Section 8.1.3.1 is waived for the Windsor 2010 Race. Specifically, after gates 5 and 12, the pilot is not required to roll to a wings level attitude before proceeding to gate 6 and 13.

“We would have put that waiver in regardless of whether Hannes’ incident had happened or not,” explained race director Drew Searle, who said the earlier training sessions were used to observe whether the waiver was necessary ahead of Saturday’s Qualifying. “Last year we had an almost identical track but we had the quadro instead of the twin knife. The twin knife is a very interesting creature and we’re still learning about it. This is the first time that we’ve actually used it at the end of a track, in other words it’s instead of the vertical turn. We were very interested to see whether this waiver was required because it’s trying to protect against another situation, which is a negative push as you go through. We needed the training sessions to assess this.”

Searle said the measure was taken with the goal of preventing a downward trajectory after leaving the tricky gate, which can be caused by the gyroscopic effect of the propeller in a knife-edge manoeuvre. He also explained that changing wind conditions were heavily influencing how the pilots flew in the track, with at least half the field switching their line from one session to another.

“For the other half it’s not an issue because they do go back to the erect attitude before they turn,” continues Searle. “Now that we’ve observed this, we’re putting in the same waiver as last year. The guys are very conscious of how their aeroplane works and the gyroscopic effect. When we designed the track we had all these considerations going in there and there’s merit for making the knife one way or the other and it ends up being a case of let’s flip a coin. In this particular situation, we flipped the coin a certain way and that meant we might have an issue with the waiver and that’s why we’ve done it. What we’re trying to do is give the guys an opportunity to just race but the original rule is in there for a safety reason which is actually not an issue in this track so we’re happy to waive it.”