Friday, December 5, 2008

Decision Attitude

Decision Altitude in instrument flying is the lowest altitude possible on a precision approach (ILS, LPV, LNAV/VNAV). At the specified altitude you either see the runway and land or fail to see the runway and immediately start the missed approach procedure. It used to be called decision height, but height is something we never really know. Altitude is what barometers measure.

But right now I have reached the decision attitude, at least in regard to instrument charts.

In the United States we have two major sources of charts, a government agency called NACO, which is an acronym for National Aeronautical Charting Office and Jeppesen, a commercial vendor. The charts show the same information with slightly different formats, and one pilot I know dismissed a rather loud airport lounge debate about which was better with "Some like chocolate. Some like vanilla." End of discussion.

Other countries have similar situations: charts come from Jeppesen or a government or at least quasi-governmental agency.

I started instrument training in 1985, and some may say that I still don't get it. No matter: since 1985 I have used Jeppesen charts for my instrument flying. A few years ago at the Oshkosh fly-in I bought a pair of beautiful green leather Jeppesen binders with Arabic calligraphy and the English legend "Royal Air Maroc B-737 Operations Manual." I kept the contents for reference; I use the binders for my charts.

[I promise to take a picture and post it over the weekend.]

But lately I have been less satisfied with the Jeppesen charts. First, they moved a lot of their NOTAMs online, which isn't much help in the cockpit. I wrote them a letter, and got a perfunctory response. And this was a big change: it used to be that Jeppesen's customer service was the best there was.

They missed a change of a Minimum Enroute Altitude (MEA), which I suppose can happen to any chart service. I found out the semi-hard way when ATC told me that I couldn't be cleared via the airway at the altitude I'd used for many years. "But my [brand new] chart doesn't show an MEA change," I complained. ATC was right.

That was the semi-hard way to discover an MEA change. The hard way would be to hit some rocks.

My flying changed, too. I'm not flying the King Airs anymore, so don't need faraway charts at short notice. The company bought Jeppesen charts for the airplanes, but I never knew who had done the revisions, and some of the pilots were better than others at refiling charts after flights. I didn't want to find myself someplace strange in the middle of the night with the approach chart misfiled. So I carried my own charts, at my own expense.

And expense has become a big issue. I got my Jeppesen renewal notice today; they want $281 for the year. But NACO charts are public domain and are available free online, from sites like, airnav, or FlightAware. A subscription to NACO charts for 99% of my flying will cost about $105, which I can pay as the charts are issued, rather than all at once. In the past few months, $176 has become a lot of money.

So the decision is made; while I'll miss Jeppesen's approach, tomorrow I plan to stop at a pilot shop and buy a couple of NACO books and an enroute chart or two.

I'll sure miss using those green binders, though. Ebay, anyone?

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