VNAV with the flight director or autopilot coupled during the climb and approach phases is not permitted except for which approaches?

• A. LPV and LNAV/VNAV approaches
• B. ILS approaches only
• C. RNAV approaches
• D. VOR approaches only

Answer: (A)

VNAV coupling relies on a defined vertical path that the airplane can trust and follow automatically. LPV and LNAV/VNAV are APV (approaches with vertical guidance) that publish a precise vertical profile, often using WAAS or baro-VNAV, so the flight computer can steer the aircraft along that path in both climb and descent. Because this vertical guidance is certified for automatic use, the flight director or autopilot can couple to VNAV during these phases and fly the approach with the vertical constraints automatically. Other approach types don’t provide the same reliable, onboard-validated vertical path for autopilot coupling in climb and approach, so VNAV-coupled control isn’t permitted for them. Hence, LPV and LNAV/VNAV are the only approaches where VNAV coupling during climb and approach is allowed.