You’re suddenly having a bad IFR day. As you approach your destination, Huron, SD, after a routine departure and a comfortable cruise in IMC, most of your panel abruptly goes dark. You still have basic flight instruments, including an electronic PFD and an HSI, which run on backup batteries. Your last communications with ATC included a clearance to an initial approach fix and “expect the ILS RWY 12 approach.” But your GPS navigator, which includes navigation receivers, is now kaput, along with your second nav/com. In other words, you have no moving map or course guidance in the panel--just attitude, airspeed, altitude, and heading. You can’t even see a GPS track indicator.
The good news is, you have an iPad with a built-in GPS (or a tablet connected to an external GPS source) running ForeFlight or a similar app. The EFB confirms that your blue “own ship” symbol is tracking toward HUMSO, an initial approach fix that marks the beginning of a feeder route that takes you to the final approach course.
Using just your track shown on the approach chart, and your basic instrument flying skills, can you fly the approach?
As you’ll see in this video, a challenge like this is an excellent workout in an aviation training device. Galvin Flying, the flight school in Seattle where I instruct, has two ATDs made by one-G. T. You can connect ForeFlight to the Wi-Fi signal broadcast by each trainer, which sends position, altitude, speed, and other information to your tablet. As far as ForeFlight is concerned, you’re flying.
Just as in the airplane, provided your EFB can receive GPS signals, you have a good 2-D navigation solution. If you can keep your blue airplane tracking along the lines on a geo-referenced approach chart, you’ll follow the intended path. What you don’t get, however, is any type of vertical guidance. It’s up to you to establish and maintain a steady descent that keeps you as close as possible to an ILS glideslope or a GPS glidepath for an approach to a DA, or to the profile for a non-precision approach to an MDA.