With apologies to Lyricist George Gershwin and singer Billie Holiday, the livin’ ain’t so easy as density altitude climbs. In the last few days we’ve had a couple of accidents that sure look like density altitude, although it’s too soon to say for sure.
Whenever I see high temperatures and high terrain I’m suspicious. When a high performance aircraft that is typically a strong performer at lower density altitudes is fully loaded, I’m almost ready to put money on it.
The two fatal accidents that appear to fit the DA profile both happened on June 29: In Santa Rosa, NM a Cessna 206 with 5 passengers was lost shortly after takeoff. One state over, at the 7,000 foot of a mountain close to North Las Vegas, NV, a Cherokee 6 also with five passengers crashed. We’ll learn more as the investigation goes forward but if this is the case, to lose 10 people in one day because the pilots forgot that sea level performance doesn’t exist in the summertime is sad, expensive, and really unacceptable.
My experience with hot and high makes me conservative on who and how much to carry. Trip legs are frequently shorter as fuel load is lightened and I really study the route carefully so as to be at altitude before getting to the high terrain, if that’s possible.
Some years ago when taking a mountain flying course, while pausing at Leadville, CO to get the certificate for being at the highest airport in the U.S. , I watched a fully loaded Cessna 172 almost do the deed. The airport picture makes it look deceptively easy. The Skyhawk is not exactly a ball of fire with all seats full at sea level. With a runway of 6,400 feet, that’s less than the field elevation of 9,927 feet msl the Cessna pilot clearly did not understand what he was up against. With four people on board the Cessna rolled and rolled and rolled. It sagged off the ground, caught its breath in ground effect and then sagged some more into the the cool thin morning air. That coolness was the only thing that saved them because by early afternoon there would have been no climb at all – only forward and down.
If you haven’t done much high terrain flying recently take a look at ASF’s mountain flying course.
As we did in talking about near fuel accidents, share your experiences that you or a “friend” had in learning about density altitude beyond the academic view. Is there a way we could be teaching this more convincingly?