BRAVE PILOTS, YELLOW ARCS

A dozen or so years ago, after the trend toward very powerful and fast turbocharged singles had begun, competition between the Lancair Columbia and the Mooney Bravo shed a fleeting light upon some odd quirks in the rules under which such aeroplanes were certificated.

- PETER GARRISON

THE COLUMBIA, YOU WILL RECALL, was a descendant of the kit-built Lancair 4 homebuilt; Lancair later changed its name to Columbia, and then sold the design to Cessna, which produced it until 2018 as the Cessna Columbia 400 and, later, TTx. The Mooney M20 Bravo became, with various evolutionary changes, the Acclaim and Ovation, and remains in production. Both aeroplanes were powered by big twin-turbo Continentals, and boasted maximum cruising speeds around 220 knots at 25,000 feet.

In a 2006 review of the Lancair Columbia in Flying Magazine, the late Richard Collins touched on an odd-seeming speed limitation, to wit, the requirement that its maximum cruising speed - the top of the green arc - diminish by 3.5 knots per thousand feet above 12,000 feet. As a result, some 45 knots have been peeled off its green arc by the time it reaches its maximum cruising altitude of 25,000 feet. This seems unfair to such a fast aeroplane, and yet it is precisely Columbia's high speed that causes it to be penalised. Except in whatever is meant by "smooth air" - we'll get to that later - some aeroplanes that have lower normal operating speeds than the Columbia end up being able to cruise faster.