Can you use a GPS approach as an alternative?

The point of the special rules using GPS as an alternate has to do with the fact that non-WAAS GPS is supplementary navigation. So you can file with the destination or the alternate having only a GPS approach, but not both. WAAS-equipped aircraft can file for destinations and alternates having only GPS approaches.



Yes, you can use a GPS approach at an alternate airport, but the rules depend heavily on the equipment installed in your aircraft. Under FAA regulations, if your aircraft is equipped with WAAS (Wide Area Augmentation System) compliant GPS (TSO-C145/146), you can plan for and use a GPS-based approach at your alternate airport, even if your destination also utilizes a GPS approach. However, if your aircraft only has a non-WAAS IFR-approved GPS (TSO-C129), you cannot plan for a GPS approach at both the destination and the alternate; if you plan to use a GPS approach at your destination, your alternate must have a functional ground-based navigation approach (like ILS or VOR) that you are equipped to fly. Furthermore, when planning for a WAAS-based alternate, you must use the LNAV (lateral navigation) minimums (typically 800-2) for flight planning purposes rather than the more precise LPV minimums, unless specific operational requirements are met.

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What this means practically is that a pilot may utilize their GPS RNAV system to actually fly along a VOR approach beyond the final approach fix as long as they can “monitor” the VOR (or TACAN or NDB) on a secondary radio and ensure that the GPS is navigating along the appropriate NAVAID course for the approach.

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According to the FAA, if you're using an airport with LPV only (no ILS or other ground-based navaid approach) as your alternate airport, you need weather minimums that meet the LNAV or circling MDA, or the LNAV/VNAV DA if you're equipped to fly it.

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Yes, you can shoot a VOR approach with GPS only as long as the title of the approach is titled, VOR/GPS. To count the approach as a VOR approach on an FAA flight test will require that the VOR be tuned to the appropriate station and identified.

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So you can file with the destination or the alternate having only a GPS approach, but not both. WAAS-equipped aircraft can file for destinations and alternates having only GPS approaches. In both cases, the weather at the time of arrival must satisfy the LNAV or circling minimums or higher if noted.

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Airports without weather reporting, or approaches with unmonitored approach equipment, can't be used as an alternate.

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14 CFR 91.169 (b) (2) (i) states that an alternate airport is not required if “for at least 1 hour before and for 1 hour after the estimated time of arrival the ceiling will be at least 2000 feet above the airport elevation and the visibility will be at least 3 statute miles.” To help remember those conditions of the ...

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LNAV approaches are less precise (556m lateral limit) and therefore usually do not allow the pilot to descend to as low an altitude above the runway.

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Many pilots refer to this as the 1-2-3 rule: Plus or minus 1 hour from arrival, ceilings at least 2,000 feet and visibility at least 3 statute miles.

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0 - Zero drinks, if you're under the age of 21. • 0 - Zero DUIs (driving while under the influence) • 1 - One drink per hour (amount of alcohol that the liver can process in one hour) • 3 - No more than three drinks of alcohol per outing.

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Many pilots use GPS as an aid to visual flight rules (VFR) navigation. The key word is aid, because VFR means seeing the terrain well enough to confirm your position on a map. Avionics used for VFR do not check for errors in satellite signals, so your GPS position could be bad.

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Long before GPS was available for aircraft navigation, VOR stations guided aviators around the world. Although this technology is aging and many VORs are being decommissioned, VORs still play an important role in aviation.

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