FAA Instrument Rating Airplane (IRA)Navigation SystemsMedium
A pilot is flying an RNAV (GPS) approach. What is the minimum required service level for WAAS to support LPV minima?
- ANon-precision approach (NPA)
- BLocalizer performance (LP)
- CStandard Positioning Service (SPS)
- DLocalizer performance with vertical guidance (LPV)
Show answer & explanationAnswer & explanation
Correct answer: D. Localizer performance with vertical guidance (LPV)
LPV minima require the highest level of WAAS service, offering precision-like performance. If WAAS downgrades below LPV, the pilot must revert to a less precise minima or execute a missed approach.
Why the other options are wrong
- A. NPA is a lower service level, not sufficient for LPV.
- B. LP is a lateral-only WAAS service, not providing vertical guidance required for LPV.
- C. SPS is the basic GPS service, without WAAS augmentation, and is not suitable for instrument approaches.
WAAS Service Levels for Approaches
WAAS provides different levels of GPS augmentation, enabling various approach minima based on accuracy and integrity.
- LPV (Localizer Performance with Vertical Guidance) offers precision-like approach minima.
- LP (Localizer Performance) offers lateral guidance only, similar to a localizer.
- LNAV/VNAV uses barometric VNAV, while LPV/LP use WAAS vertical guidance.
Memory trick: LPV is the top tier for WAAS approaches.