Insights

It's head up, not head down

An FAA designated pilot examiner berated a certificated flight instructor (CFI) candidate for not using a plotter and flight computer when performing a diversion and lost procedure. Flight safety is a critical CFI function; it's incredible that a pilot examiner would be ignorant of the compromised flight safety caused by that mandate.

With respect to a diversion, the FAA's Pilot's Handbook of Aeronautical Knowledge, FAA-H-8083-25, states the following: "Computing course, time, speed, and distance information in flight requires the same computations used during preflight planning. However, because of the limited cockpit space, and because attention must be divided between flying the airplane, making calculations, and scanning for other airplanes, take advantage of all possible shortcuts and rule-of-thumb computations.

"When in flight, it is rarely practical to actually plot a course on a sectional chart and mark checkpoints and distances. Furthermore, because an alternate airport is usually not very far from your original course, actual plotting is seldom necessary. A course to an alternate can be measured accurately with a protractor or plotter, but can also be measured with reasonable accuracy using a straightedge and the compass rose depicted around VOR stations. This approximation can be made on the basis of a radial from a nearby VOR or an airway that closely parallels the course to your alternate."

After aeronautical navigation charts, pilotage, and dead-reckoning navigation have been mastered, I teach students mini-reckoning, a useful technique for short-range navigation when the radio navigation receivers are unusable.

Imagine that you are flying westbound in hazy conditions, and the afternoon sun reduces forward visibility from the prevailing five miles to about one mile. You can't find your destination airport, but you do see a dam that was one of your checkpoints.

Return to the dam and circle it while you do the following: Bend the fingers on your right hand into a U shape. One of the middle segments (my little finger works perfectly) will represent 10 miles on a sectional chart, or five miles on a terminal chart. Now measure the approximate distance from the dam to the airport.

Next, determine the magnetic course from the dam to the airport by placing a pencil or the edge of a checklist on that course, and while keeping it parallel to the course, slide it over to the center of a nearby VOR compass rose in order to determine your magnetic course. (For more on this technique, see "Looking for Lower," October 2005 AOPA Flight Training.)

Estimate your ground speed in miles per minute (mpm). Sixty knots is one mpm, 120 knots is two mpm, 180 knots is three mpm. If the distance to fly was eight miles and estimated groundspeed was 140 knots (about two mpm), time to the airport will be a little less than four minutes.

Estimate your wind correction angle by dividing the forecast wind velocity by your mpm. If wind velocity was 10 knots and your true airspeed (indicated airspeed plus 2 percent per thousand feet) was around two mpm, your wind correction angle would be approximately 5 degrees (10 divided by 2) for a direct crosswind. Reduce it for a quartering wind.

Note the time, and turn to your compass heading. After three and one-half minutes, start a steep-bank left turn. Your destination airport will be below, close to your position.

When possible, use land-fall navigation in order to avoid a "Do I turn right or turn left?" dilemma when you arrive at a prominent reference (a river, shoreline, or highway, for instance) that you're relying on for navigation. Change your planned heading 10 to 20 degrees, so that when you reach that reference, you'll know which way to turn.

"In every cloud there's a silver lining," and that's certainly true in the case of diversion and lost procedures. It's GPS, which blasts the aforementioned procedure into the history books. Select Nearest on your GPS receiver, select a suitable airport, and select Direct-TO. Problem solved.

You can be certain, however, that as long as aerial navigation relies on electrons, on your checkride you will be required to perform the diversion problem the old-fashioned way.

Ralph Butcher, a retired United Airlines captain, is the chief flight instructor at a California flight school. He has been flying since 1959 and has 25,000 hours in fixed- and rotary-wing aircraft. Visit his Web site.