Custom content for the Feb. 10, 2012, issue of 'AOPA ePilot'

training tips

A tailwind on base

It's a good day for some practice in the traffic pattern. The wind is blowing, but well within your logbook limitations, and it's a direct crosswind—a tantalizing opportunity to nail a few crosswind landings using the techniques you have learned.

Sure enough, immediately after takeoff you sense the crosswind's effect on your track, so you set up a crab angle to track the extended runway centerline in the climb. Once you get established on the downwind leg at pattern altitude, it will be necessary to set up a crab angle there too.

There's an even more important element of this common scenario to consider: Will today's crosswind give you a tailwind or a headwind on the base leg? Knowing which to expect is essential for avoiding overshooting the turn to final—a problem that leads to many go-arounds and occasional accidents resulting from steep or uncoordinated maneuvering by pilots too stubborn—or too rattled—to abandon the approach and try again.

Suppose you are flying a left downwind, crabbed a few degrees to the right to prevent your aircraft from drifting closer to the runway. That wind condition promises a tailwind—and an increase in your groundspeed—starting when you turn base. If you flew your downwind leg too close to the runway, now you're set up to overshoot the turn to final.

On the other hand, if your crab angle on that downwind must be to the left (that is, a few degrees toward the runway), you can expect a headwind, and reduced groundspeed, on base.

At a tower-controlled airport it may be possible to arrange to fly both left- and right-hand traffic patterns so that you can experience both effects during your practice session. Considering that in an eight-knot direct crosswind, the difference in your groundspeed will be 16 knots between a left base leg and a right base leg flown at the same indicated airspeed, it's an eye-opening exercise.

Any time you have to land with a crosswind, the other pattern legs will need adjustment as well. If that means that you can expect a tailwind on base, fly a traffic pattern that gives you enough room, and enough time, to make a smooth, accurate turn onto final approach. A review of the Air Safety Institute's Mastering Takeoffs and Landings Safety Advisor will help broaden your understanding even further.

training products

DRE 8001 ANR headset with Bluetooth

The DRE 8001 active noise reduction (ANR) headset is now available with Bluetooth capability. Sold by Headsets Inc., the unit integrates a Lynx Bluetooth audio controller into the headset. The Lynx unit features rechargeable lithium-ion batteries that can be recharged by plugging into the included charger, plugging into a computer USB port with the included cable, or from aircraft power via the included cigarette lighter adaptor. The battery will power the unit for 12 to 15 hours. The DRE 8001 with Lynx Bluetooth interface is available at an introductory price of $599 through June 30. See the website.

Note: Products listed have not been evaluated by ePilot editors unless otherwise noted. AOPA assumes no responsibility for products or services listed or for claims or actions by manufacturers or vendors. 

final exam

Question: I am familiar with instrument (IR) and visual (VR) military training routes (MTR) consisting of three or four digits. The other day, I was looking on the Jacksonville Sectional and I noticed that there are VR and IR routes with only two digits. I've never seen those before. Are they the same as those with three and four digits?

Answer: Yes. IR or VR routes that include one or more segments above 1,500 feet above ground level are identified by three numbers, and IR or VR routes with no segment above 1,500 feet agl are identified by four numbers. Now you might be saying, "What about routes such as IR18 near St. Simons Island, Ga., or VR45 or VR25 south of Savannah/Hilton Head International Airport?" They only have two digits. Well, the actual assigned number is 018, 045, or 025, respectively. When they are charted the preceding zero is dropped. There are more than 500 military training routes (MTRs) across the country divided up roughly equally between visual routes and instrument routes. The numbers associated with these routes are assigned by region. The nine regions are Southern, Southwest, Western-Pacific, Northwest Mountain, Central, Great Lakes, Eastern, New England, and Alaska. Numbers 001-099 are assigned to MTRs in the Southern region. 

Got a question for our technical services staff? E-mail [email protected] or call the Pilot Information Center, 800/872-2672. Don’t forget the online archive of “Final Exam” questions and answers, searchable by keyword or topic.