AOPA Pilot Magazine - November 2011 - 100

DOGFIGHT | NDB APPROACHES
Editor at Large Tom Horne and Senior Editor Dave Hirschman have a lot of things in common: lots of ratings, lots of experience in lots of airplane models—and lots of opinions (as well as similar haircuts). We last turned them loose on the topic of production and Experimental aircraft (see “Dogfight: Experimental Versus Standard,” September 2011 AOPA Pilot) and the response to two different schools of thought on this topic garnered interesting opinions from a large number of readers (see “Letters,” page 22). So we launch them into another “Dogfight”—we hope you’ll enjoy these two takes on a topic, and keep those cards and letters coming. —Ed.

NDBs are your friends
Why trash a perfectly good system?
BY THOMAS A. HORNE >

hile I’ve never been a big fan of flying automatic direction finding (ADF) approaches, holds, and other procedures, I had to come to terms with them during my instrument training. Eventually, I became fairly good at flying the heading-adjustment procedures necessary to make good a track. Learning was difficult, but certainly rewarding. And I picked up a skill set that has served me well. Lately, the trend has been to do away with ADF approaches (sometimes called NDB approaches, for the nondirectional beacon stations that put out the signals). Oh, joy, I hear so many say. No more mental math to come up with proper headings! No more memorizing MH (magnetic heading) plus RB (relative bearing) equals MB (magnetic bearing) to the station! No more flying the least precise of the nonprecision approaches! No more stressful inflight quandaries about the quality of your track! Believe me, I understand those feelings. But there are several very important reasons for obtaining and maintaining ADF skills. Yes, yes, I know that if the airplane you use for passing an instrument rating checkride isn’t equipped with an ADF you needn’t demonstrate ADF skills. But that’s a pretty weak reason for not building a complete set of navigation abilities. Here’s why. Believe it or not, some airplanes are still delivered with ADF equipment fresh from the factory. Thousands more ADFs are in the total aircraft fleet. Some day you may find yourself behind the wheel of an airplane with a navigation system that you’re unable to safely use.
AOPA PILOT •

But there are fewer ADF approaches these days, I hear you say, and GPS overlays obviate the need for NDB tracking. Yes and no. At some smaller community airports an ADF approach (sorry, without GPS overlays) either to or from the NDB station remains the only way to make an instrument arrival. Ever plan on flying to Canada, the Caribbean, or overseas? Then you’d better know how to track NDB bearings. In many parts of the world there are even NDB airways. Care to accept a clearance to track a low-

Why would you knowingly want to do away with a second source of navigation information?
frequency airway to an airport served by an NDB-DME approach? You’d better, if you want to qualify to fly outside the U.S. Redundancy is another good reason for having an ADF in the cockpit. To those who cheer the NDB’s (apparent) demise, I have a question: Why would you knowingly want to do away with a second source of navigation information? It may come in very, very handy one day. GPS outages do occur. Emergencies do happen, and a quick landing at the nearest airport—served, you guessed it, by a sole NDB—may be the only option. It’s happened to me. Last but not least is the vital issue of situational awareness. Sure, seeing your position on a huge GPS display screen

is hard to beat. Unless your airp l a n e d o e s n’t have one; or unless you’re cleared to hold at an NDB; or unless you’re told to intercept and track an NDB bearing; or unless you’re attempting to ascertain your position in a nonradar environment with no access to GPS information. ADF skills give you the kind of basic visualization, tracking, and orientation aptitudes that have staying power. And it’s not that difficult to learn; if you can become proficient understanding the use of VOR cross-bearings for position finding, then you can become a whiz at using an ADF for position fixing. A slaved radio magnetic indicator (RMI) makes this chore even easier because the compass card shows the airplane’s current heading, as well as real-time compass bearings to NDBs or VORs. So are ADFs useless, and the skills to use them as arcane as those used in operating an abacus? I think not. Knowing how to use an ADF is the sign of a pilot with a well-rounded education. Too bad virtually all aircraft manufacturers no longer offer them, or if they do it’s as optional equipment. Email the author at tom.horne@aopa.org.

100 • NOVEMBER

2011

AOPA Pilot Magazine - November 2011

Table of Contents for the Digital Edition of AOPA Pilot Magazine - November 2011