LOCALIZER BACK COURSE

In cases where an ILS is installed, a back course may be available in conjunction with the localizer. Like the localizer, the back course does not offer a glide slope, but remember that the back course can project a false glide slope signal and the glide slope should be ignored. Reverse sensing will occur on the back course using standard VOR equipment. With an HSI (horizontal situation indicator) system, reverse sensing is eliminated if it is set appropriately to the front course. [Figure 5-57 on page 5-66]

Figure 5-57. Baton Rouge Metro/Ryan (KBTR), Baton Rouge, Louisiana, LOC BC RWY 4L.

LOCALIZER-TYPE DIRECTIONAL AID

An LDA is a NAVAID that provides nonprecision approach capabilities. The LDA is essentially a localizer. It is termed LDA because the course alignment with the runway exceeds 3 degrees. Typically, an LDA installation does not incorporate a glide slope component. However, the availability of a glide slope associated with an LDA is noted on the approach chart. This type of NAVAID provides an approach course between 3 and 6 degrees, making it similar in accuracy to a localizer, but remember that the LDA is not as closely aligned with the runway and it does not offer a navigable back course. Currently there are less than 30 LDA installations in the U.S., and as a result, most pilots are not familiar with this type of instrument approach. [Figure 5-58]

Figure 5-58. Hartford-Brainard (KHFD), Hartford, Connecticut, LDA RWY 2.