FCOM 2 pg. 4.10.13 Personal note: You MUST push B/CRS switch first, then LOC 3 Backcourse (B/CRS) Switch Push – (Must be used concurrently with LOC switch), arms or engages AFDS in B/CRS mode as follows: B/CRS appears on each FMA prior to localizer capture. • AFDS is armed to capture and track inbound on backcourse of localizer • capture point varies based on range and intercept angle • initial roll modes; LNAV, HDG SEL or HDG HOLD remain engaged until B/CRS capture • before localizer capture, pushing the LOC switch a second time disarms both the LOC and B/CRS modes. Pushing only the B/CRS switch a second time, disarms the B/CRS mode but the LOC mode remains armed B/CRS appears on each FMA after localizer capture. • AFDS tracks inbound on backcourse • if the LOC switch is selected and localizer is captured before B/CRS switch is pushed, AFDS will track the localizer front course (outbound) and B/CRS cannot be selected • G/S, FLARE and ROLLOUT functions are not available Note: The B/CRS mode is a single autopilot function only. Multiple autopilots cannot be engaged with this mode. ------------------------------------------------------------------------------------------------------------FCOM 1 pg. NP .21 .51 & NP .21 .52 Landing Procedure - Non-Precision VNAV/Vertical Speed Approach Note: ATI crews may utilize the VNAV MCP mode for vertical path guidance to fly a Non-Precision Approach down to an MDA + 50’ Derived Decision Altitude (DDA). ATI does not have OPSPEC approval to request, accept, or initiate, a Non-Precision Approach Procedure that includes a VNAV DA(H) in lieu of an MDA(H). These approaches are characterized by a Glide Path angle depicted in the FMC down to a Decision Altitude. Non-Precision Approaches include: VOR/DME RNAV, NDB, NDB/DME, LOC, LOC BC, LOC/BC/DME, LOC/DME, NBD, NBD/DME, SDF, VOR, VOR/DME, VOR/DME/LOC, LDA, and RNAV (GPS) Use the autopilot during the approach to give: • Autopilot alerts and mode fail indications. • More accurate course and glide path tracking. • lower RNP limits Continuous Descent Final Approach (CDFA) Technique will be employed for flying the final approach segment (FAS) of the instrument approach procedure (IAP) using either Baro-VNAV as a reference or Vertical Speed (VS) FMS functions with vertical flight path deviation guidance. This procedure is not authorized using QFE. FCOM 1 pg. NP .21 .51 & NP .21 .52 (USE LNAV for a B/CRS) How To Set Up A "LOC BC" (With HSI) If you're lucky enough to fly with a horizontal situation indicator (HSI), flying LOC BC approaches gets significantly easier. The HSI combines a heading indicator with CDI needles. As long as you tune the front course for the localizer, you won't get reverse sensing. When configured properly, you can fly the LOC BC approach with normal sensing, and fly "to the needle" like you do in all other navigation. For example, if you were flying the LOC BC to runway 17R in Grand Forks, instead of dialing the back course of 174 degrees, you'd dial the front course of 354 degrees, and fly to the needle to navigate the approach. hsi back course Flying The LOC BC Approach Once you're established on a LOC BC approach, flying is as simple as any non-precision approach. You'll reference step down fixes and DME before leveling off at your minimum descent altitude (MDA). Unlike most localizer approaches, expect a missed approach point on a LOC BC approach to be located more than half a mile before the runway. The reason? It would be impossible to fly all the way to the runway threshold at MDA on a LOC BC approach. As you get closer and closer to the localizer antenna, it becomes increasingly difficult to stay on course due to increasing signal sensitivity. Since the localizer system you're using for the back course is located near the runway threshold, as opposed to the departure end, the missed approach point is farther away from the runway. missed approach point You will be making a manual descent to the MDA as there is no glide path guidance with a Back Course approach. The FAA offers a warning about flying back course approaches: "False glide slope signals may exist in the area of the localizer back course approach which can cause the glide slope flag alarm to disappear and present unreliable glide slope information. Disregard all glide slope signal indications when making a localizer back course approach unless a glide slope is specified on the approach and landing chart." Using An Autopilot? PUSH THE "BACK COURSE BUTTON" When you fly an autopilot-coupled LOC BC approach, ALWAYS push the "back course button" if there's one installed for your autopilot system. By pushing this button, you're telling the autopilot to turn inbound on the back course instead of outbound. Here's the scenario... If you're flying with an HSI, you should have tuned the front course for the localizer to avoid reverse sensing. Your CDI needle will thus point away from the runway. If ATC clears you to track inbound on the localizer and you click "NAV" mode on the autopilot, the autopilot will turn the wrong way, outbound! The autopilot doesn't know that you're flying a back course approach. If you've engaged NAV mode, it will intercept and fly the course you've set. By pushing the "BC" button, you're telling the autopilot to track inbound on the back course, which will avoid you making an inadvertent and potentially dangerous outbound turn. autopilot back course button Think you're ready to fly the approach? Take this quiz: Could You Fly This Localizer Back Course Approach? How many times have you had to fly a LOC BC approach? Tell us in the comments below. ============================================================================== ================== The Localizer Back Course The localizer antenna array is located at the far end of the runway, away from the approaching aircraft. Its antennas are arranged and manufactured in such a way to transmit a narrow signal on the runway approach path. That localizer signal is so accurate that with its guidance, along with the glide slope signal, an aircraft can safely land when the visibility is zero and when the ceiling is zero. However, the Localizer antenna array also radiates a narrow signal beam in the opposite direction of the approach path. That signal is called the Localizer Back Course. A prime advantage of the Back Course is that the airport gets it for free. It need only be tested and certified to become available to pilots "coming in from the other direction." Approach plates are published specifically for the localizer back course. Too many pilots shy away from a back course approach because of the reverse sensing of the needle. On the back course, one must correct drift with a turn away from the needle. Keep your wits about you, though, and you will quickly master the reverse sensing needle. The Back Course localizer approach is a non-precision approach. There is no glide-path guidance with it. Glide-path signals from the front course may be received while on the back course, but you should ignore them. Crossing the IAF (Initial Approach Fix) begin your descent. Remember, this is a manual descent to the MDA as there is no glide-path guidance. Upon reaching the MDA you may fly that altitude until reaching the DME of the Missed Approach Point (MAP), at which you must see the runway for landing OR fly the missed approach. =========================================================================== FCOM 2 pg. 4.10.13 Personal note: You MUST push B/CRS switch first, then LOC 3 Backcourse (B/CRS) Switch Push – (Must be used concurrently with LOC switch), arms or engages AFDS in B/CRS mode as follows: B/CRS appears on each FMA prior to localizer capture. • AFDS is armed to capture and track inbound on backcourse of localizer • capture point varies based on range and intercept angle • initial roll modes; LNAV, HDG SEL or HDG HOLD remain engaged until B/CRS capture • before localizer capture, pushing the LOC switch a second time disarms both the LOC and B/CRS modes. Pushing only the B/CRS switch a second time, disarms the B/CRS mode but the LOC mode remains armed B/CRS appears on each FMA after localizer capture. • AFDS tracks inbound on backcourse • if the LOC switch is selected and localizer is captured before B/CRS switch is pushed, AFDS will track the localizer front course (outbound) and B/CRS cannot be selected • G/S, FLARE and ROLLOUT functions are not available Note: The B/CRS mode is a single autopilot function only. Multiple autopilots cannot be engaged with this mode. ------------------------------------------------------------------------------------------------------------FCOM 1 pg. NP .21 .51 & NP .21 .52 Landing Procedure - Non-Precision VNAV/Vertical Speed Approach Note: ATI crews may utilize the VNAV MCP mode for vertical path guidance to fly a Non-Precision Approach down to an MDA + 50’ Derived Decision Altitude (DDA). ATI does not have OPSPEC approval to request, accept, or initiate, a Non-Precision Approach Procedure that includes a VNAV DA(H) in lieu of an MDA(H). These approaches are characterized by a Glide Path angle depicted in the FMC down to a Decision Altitude. Non-Precision Approaches include: VOR/DME RNAV, NDB, NDB/DME, LOC, LOC BC, LOC/BC/DME, LOC/DME, NBD, NBD/DME, SDF, VOR, VOR/DME, VOR/DME/LOC, LDA, and RNAV (GPS) Use the autopilot during the approach to give: • Autopilot alerts and mode fail indications. • More accurate course and glide path tracking. • lower RNP limits Continuous Descent Final Approach (CDFA) Technique will be employed for flying the final approach segment (FAS) of the instrument approach procedure (IAP) using either Baro-VNAV as a reference or Vertical Speed (VS) FMS functions with vertical flight path deviation guidance. This procedure is not authorized using QFE. FCOM 1 pg. NP .21 .51 & NP .21 .52 (USE LNAV for a B/CRS)
