Plane & Pilot
Thursday, September 1, 2005

The Go/No-Go Decision

It’s better to be safe than sorry

The following day, I calculated the winds for each of the eight zones over the 2,100 nm between Oakland and Honolulu. In contrast to the surprisingly wet winter we had in Southern California this year, the second wettest in history, and the accompanying strong headwinds going to Hawaii, the overall component was slightly favorable plus three (a three-knot tailwind), but even with that miniscule help, the time en route came out to 13 hours and 42 minutes. In theory, that number would give me only one hour and 18 minutes of reserve.

No-go, not even close. If you’re flying a four-hour cross country over land with dozens of airports within easy divert range, you may be able to justify flying with an hour of reserve. If you’re only in the air for four hours, any unforecast headwind or nasty weather has little time to develop, and its impact on your time en route is minimal. When the flight leg stretches to 13 hours or more, any change in the wind is obviously magnified.

My buddy Jeff Kopps of the National Weather Service in Monterey, Calif., is one of those folks whose forecasts of wind and weather are almost eerily accurate. (Don’t call him unless you’re going across the pond. He doesn’t do local forecasts.) I have sometimes come within two minutes of the flight plan on a 13-hour flight to Hawaii with the benefit of Jeff’s almost “Twilight Zone” accurate forecasts. That’s not a function of my brilliant navigating or flight-planning skills, by the way. I merely punch the numbers into the electronic E6B and copy down the results.

Still, even the best weather computer models miss the mark sometimes. Back in the mid-1990s, fellow pilot Jon Egaas and I launched from Santa Barbara, Calif., John in a huge, yellow, turbine-powered Ayres Thrush crop-duster (he called it his “kerosene school bus”) and me in a new Mooney MSE, both headed for Hawaii and on to Australia. Loaded heavy, we were about evenly matched at an initial 150 knots.

Right out in the middle, 1,000 miles from any place with a name, we ran into weather that beat us all over the sky. John diverted to Hilo, Hawaii, and landed on fumes in a near zero-zero rainstorm, and I struggled into Honolulu in better weather with eight gallons remaining, about 45 minutes of reserve. Even in an MSE, that’s too close.


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