One challenge for instrument pilots is that the rapid change in technology found elsewhere in our lives has invaded the cockpit. In the past, pilots had it easy when flying an ILS (instrument landing system) approach. By dialing in the right frequency and keeping the needles centered, a pilot could successfully fly an approach even using radios he or she had never seen before.
GPS changed everything. If you know how to operate a particular GPS model and can successfully load a GPS approach, flying an approach to LPV minimums can be as simple as flying an ILS approach. Of course each GPS is different and the odds of successfully loading an approach on an unfamiliar GPS are slim. So flying a GPS approach to LPV minimums can be as simple as flying an ILS approach, but only if you’re extremely familiar with the GPS in your cockpit.
That said, flying a GPS approach can be so complicated you could write a book about it. So I did; much of what you’ll read here comes from my Max Trescott's GPS and WAAS Instrument Flying Handbook.
Technically there is no such thing as an “LPV approach.” Instead, LPV is just one of several minimum types that can be flown on a GPS approach with a WAAS-capable, instrument-certified GPS. LPV stands for “localizer performance with vertical guidance,” meaning it’s similar in precision to the localizer and glideslope of an ILS approach.
LPV minimums, usually 200 or 250 feet agl, are typically the lowest available on a GPS approach. Other minimum choices may include LNAV/VNAV, LP, LNAV and circling. You can usually ignore the LNAV/VNAV minimums, since LPV minimums are almost always lower. LP, or localizer performance, minimums are like a localizer approach; the angular guidance narrows as you near the runway and there’s no vertical guidance.
LNAV, or lateral navigation, mini-mums are used to fly a series of stair steps until you reach a minimum descent altitude (MDA). They are the only straight-in GPS minimums that can be flown with a non-WAAS, approach-certified GPS. Circling minimums permit you to circle to land on any runway, except those prohibited in the chart notes.
Flying an approach to LPV minimums starts long before you reach the approach. Your preparation before leaving the ground should include checking that your GPS database and charts are current — and if your charts are on an iPad, checking that the iPad is fully charged. You’ll also want to contact Flight Service for any WAAS notams. If flying in oceanic or remote areas, the FAA requires that you run an FDE prediction program, available from Garmin and other companies, to check GPS satellite coverage.
