Waypoints: Aha moments

Ground school in the late 1970s was not a pleasant experience, at least the part I didn’t sleep through. Ten weekly evening sessions with an instructor attempting to convey complex subjects using only a chalkboard and an overhead projector. Our homework consisted of dissecting difax weather charts and studying government-created textbooks, each two inches thick.

I suppose somewhere in that steamy word cloud the phrase “density altitude” was uttered. But learning to fly in cool and relatively low-altitude northwestern Pennsylvania, the notion that temperature and altitude would collude to degrade aircraft performance never reared its ugly head. Later, basing out of Frederick, Maryland—elevation 303 feet msl—density altitude continued to be a foreign concept. Sure, I read accident reports and heard other pilots talk about how you had to lean the engine and expect longer takeoffs, but there was no evidence for me as I flew up and down the East Coast.

I was excited about the opportunity to fly a brand- new Bellanca Super Viking from the 1992 AOPA Expo in Las Vegas back to Frederick. I had flown the model once before. In preparation for the trip, I reviewed the aircraft specs and took a crash course, so to speak, in the sophisticated Bendix/King KLN 88 loran from one of the sales guys in the exhibit hall.

The flight down across Lake Mead, over the Hoover Dam and across the Grand Canyon was stunning. I followed breathtaking landscapes northwest to Monument Valley and flew in awe of colorful rock formations, my first trip through that region. Soon I entered KFMN, Farmington, New Mexico, into the loran and landed on the 6,700-foot runway. Dinner at the Mexican restaurant on the field was terrific.

Maybe that 6,700-foot runway should have been a clue to me, or the fact that I was huffing and puffing a bit as I lugged my suitcase across the ramp the next morning.Maybe that 6,700-foot runway should have been a clue to me, or the fact that I was huffing and puffing a bit as I lugged my suitcase across the ramp the next morning, a chill in the air. I remember noting it odd to see the altimeter set to 5,500 feet on the ground, higher than my cruising altitude most of the time back East. Ignorance is bliss; I cranked up the Continental engine and taxied out. Normal runup—was that a little roughness? Only my second takeoff in this airplane, I declared it normal. I shoved the throttle all the way in and we began a sachet down the long strip of pavement. Everything looks good, except maybe that rpm is a little low? Still, it seems OK. Was it like that yesterday?

As I’m rolling these questions around in my head, it eventually occurs to me that, hey, we’re taking a while to get to 70 knots. The pavement is scrolling by at a good clip, yet we’re not flying.

Aha! Density altitude! This is what it looks like. I grabbed the mixture control and pulled it back a bit and then a bit more. Did the manifold pressure pick up? I think it did. By now on this cool morning, the hefty Continental had done its job—despite my poor management of it—and we were climbing away, although slowly; the nearby rocks not quite so scary. Imagine had I been fully loaded and the temperature had been 85 degrees Fahrenheit rather than 65.

I’ve never forgotten that “aha moment,” but the incident flashed back to me as I stood on the ramp recently at Prescott, Arizona, elevation 5,000 feet, as one Cessna 172 after another lifted off from the Embry-Riddle Aeronautical University flight training program. Those students are getting real-world lessons in density altitude from day one.

One of the fascinating things about aviation for me is the knowledge that there’s always something I don’t know, that there’s something I haven’t yet experienced. The quest for knowledge and skill can never completely prepare you for every situation. But hopefully, when the next aha moment shows up, we’ll have just enough knowledge and skill to fly out of it, learning once again.