Localizer Performance with Vertical Guidance (LPV) Approach

LPV Approach
Example of an LPV Approach. Photo © FAA

What is an LPV approach?

A localizer performance with vertical guidance (LPV) approach is a modern instrument approach procedure that uses wide area augmentation system (WAAS) and very precise GPS capabilities to attain an airplane's position, offering the most accurate position available today. An LPV approach can get a pilot down to a 200-foot or 250-foot decision altitude, making it possible for aircraft to land at runways in very low visibility.

Without WAAS capabilities - without the ability to fly the LPV approach - extremely poor visibility conditions at the airport of intended landing might otherwise require the pilot to fly to an alternate airport.

LPV approaches, and WAAS-capable aircraft, in general, open up new options for pilots. With properly-equipped aircraft, operators will save time and money by using WAAS as an extremely precise navigational aid. In addition, aircraft pilots will be able to complete landings at airports where they couldn't land before, including remote airfields or approaches not easily supported by radio navigation, in worse weather than they're used to. Instead of relying on radio navigation, pilots can count on an extremely precise and stable satellite navigation system. This precise type of navigation allows pilots to descend to lower altitudes without visual references, or while still in the clouds.

 

As of November 2015, there were almost 4,000 LPV approaches published, according to the FAA.

How it Works

An LPV approach is similar to an LNAV/VNAV approach, but is more precise and can allow descent to minimums of 200-250 feet. WAAS capabilities are required for precise lateral and vertical guidance, classifying it a precision approach, where the LNAV/VNAV approach is non-precision.

In fact, an LPV approach is almost identical to an instrument landing system (ILS), but is more accurate and since it utilizes satellite technology. And no expensive ground equipment is necessary, meaning less downtime and outages. This also means the cost is less, as there is no equipment and no regular maintenance needed.

How Does WAAS Work?

The WAAS takes the error out of typical GPS signals by analyzing the GPS data at a master station and then sending the corrected data information to GPS receivers. The receivers, in turn, are able to remove any GPS errors, making the GPS information even more error-proof and allowing for a more precise result.

Why WAAS is Better

GPS accuracy is improved from about 100 meters with regular GPS service to about seven meters with WAAS, leaving hardly any room for error, and providing the most precise navigational tool to date.

WAAS will benefit the national airspace system as a whole by increasing capacity, utilizing runways more efficiently, reducing equipment costs both onboard and on the ground, and increasing approach capabilities.

Also Known As:

LPV Approach, WAAS Approach, Localizer with Vertical Guidance