EAA Sport Aviation - February 2009

One of the cool aircraft mods on the market today is the AOA indicator system sold by Alpha Systems. Using a small probe that mounts through one of the aircraft’s wing inspection covers, the AOA system transmits the relative pressures from under the wing to either a mechanical or electronic gauge on the panel. This indicator shows the pilot what the angle of attack is for the wing and how much “lift reserve” is left before the wing will stall. Because it’s not affected by temperature, altitude, or aircraft weight, it makes it possible to fly a more stable approach and land with less kinetic energy than you would by using the same approach airspeed for all conditions.

Alpha Systems AOA systems sell for $550 to $895. While they are not certified flight instruments, the company has a number of letters available from FAA FSDOs that have reviewed the system and approved it for installation as a minor modification (no 337 required). Advanced Flight Systems is another AOA instrument manufacturer. Its systems are specifically designed for experimental aircraft and utilize holes on the top and bottom of the wing instead of a probe. Prices for their systems range from $890 to $1,495.

It’s hard to fight the ravages of time for us mortals, but it’s a different story for our aircraft. With a little investment and sweat equity, we can actually improve our aircraft with age. All it takes is a plan for constant improvement, and the willingness to make small investments over time to keep making our birds better.

Jeff Simon is the president of Approach Aviation, a provider of educational products, tools, and supplies for aircraft owners. To learn more about aircraft ownership and maintenance, visit Approach Aviation at www. ApproachAviation.com or call, toll-free, 877-564-4457.