Why Does Knowing Your RNAV Capabilities Matter?
The Instrument Practical Test will include questions about determining your aircraft's RNAV capabilities. Whether you're preparing for a checkride or evaluating avionics on a new or used aircraft, understanding these limitations is essential for legal IFR operations.
This example uses a Cirrus SR-22 with factory-installed Perspective avionics. Part 2 covers Cessna G1000 aircraft and older airframes with aftermarket GPS installations.
How to determine RNAV capabilities for IFR flight planning
Consider this scenario: You're conducting a multi-day ferry flight of a Cirrus SR-22 from Duluth, MN (KDLH) to Camarillo, CA (KCMA). This is exactly the type of situation you might face during an instrument checkride oral exam.
It's the night before your final leg from Page, Arizona (KPGA) to Camarillo. Previous legs were VFR, but tomorrow's weather at KCMA is forecast at 900-foot ceilings and 5 miles visibility.
Camarillo has two GPS approaches: RNAV Z 26 with LPV minimums of 250 feet AGL and 3/4 mile visibility, and a non-LPV GPS approach. Either will get you below the ceiling. Your filed route staying at or below 10,000 feet: PGA V208 TBC V210 BASAL V12 PMD V386 FIM SESPE direct KCMA.
Your alternate is KWJF (General William J Fox Field), which is on your route, less than 50 miles from destination, and forecasting clear skies. For this exercise, assume the Hector (HEC) and Palmdale (PMD) VORs are out of service.
Reading the AFM Section 2: Limitations
Where to find RNAV approval documentation
Check AFM Section 2: Limitations to determine which procedures and routes your aircraft is certified to fly. Below are excerpts from a Cirrus Perspective AFM showing the key certification information.
Understanding your approach authorization
Working backward from the destination: You're legal to fly KCMA RNAV Z 26 with LPV approach minimums. Item 4 (sections i and l) in the AFM shows the Perspective avionics package is approved for SBAS (Satellite-Based Augmentation System) navigation, which in the US is called WAAS (Wide Area Augmentation System). The system is also certified to perform LPV approach operations.
What you cannot fly
Radius-to-fix (RF) procedures are not listed in the limitations section, meaning your avionics cannot fly RF approaches such as RNAV (RNP) Z RWY 6. This is true for G1000 and most general aviation GPS units.
Alternate airport requirements
Your alternate (KWJF) has only a GPS-based approach since PMD is out of service. Item 4(h) specifies the equipment meets TSO-145 and TSO-146 requirements for WAAS-capable GPS. Per AIM 1-1-18(c)(9), you can plan a GPS-based approach at both destination and alternate.
En route navigation
You're legal to file using the out-of-service Palmdale and Hector VORs. TSO-146 (WAAS) GPS does not require the planned route to remain within conventional navaid service volumes. WAAS GPS is a standalone suitable navigation source for the route, assuming no GPS or WAAS outages.
Filing at MOCA altitudes
Departing Page, your GPS allows you to select 10,000 feet instead of 16,000 feet (the MEA is 14,500 on V210 between Tuba City and Grand Canyon). The MOCA is 9,600 feet, which provides terrain clearance, and GPS guarantees navigation reception. Filing based on MOCA has been allowable with WAAS GPS for navigation since 2017.
Continue to Part 2: G1000 Cessna aircraft and vintage airframes with aftermarket GPS for additional examples.
Master RNAV procedures before your checkride
Understanding AFM limitations is one thing, but flying LPV approaches with precision requires practice. Our G1000 NXi simulator lets you practice every RNAV procedure discussed in this article, from LPV approaches at minimums to filing routes at MOCA altitudes with GPS navigation.
Our instructors are active airline pilots who understand both the regulatory requirements and the practical skills needed to pass your instrument checkride. Whether you're preparing for the oral exam questions about RNAV capabilities or need to sharpen your GPS approach technique, simulator training provides the focused practice you need.
Frequently Asked Questions
LPV approaches require WAAS GPS certified to TSO-C146 with explicit LPV authorization in the AFM. The GPS must have SBAS (Satellite-Based Augmentation System) capability—in the US, this is WAAS (Wide Area Augmentation System). Check AFM Section 2: Limitations for statements like "approved for SBAS navigation" and "LPV approach operations." Non-WAAS GPS (TSO-C129 or TSO-C145 without WAAS) cannot fly LPV approaches.
GPS TSO certification is documented in AFM Section 2: Limitations or in the AFM supplement for your specific GPS unit. Look for references to TSO-C145 (non-WAAS GPS), TSO-C146 (WAAS GPS), or TSO-C129 (older GPS units). Factory-installed avionics (like Cirrus Perspective or Cessna G1000) include this in the primary AFM. Aftermarket GPS installations (GTN750, GNS530W) have a separate AFM supplement that must be aboard the aircraft.
Yes, if your GPS meets TSO-C145 or TSO-C146 (WAAS) requirements. Per AIM 1-1-18(c)(9), WAAS-equipped aircraft can plan GPS-based approaches at both destination and alternate airports. This is a significant advantage when VORs are out of service or the only approach available is RNAV. Verify your specific AFM authorizes this capability—look for language about "standalone suitable navigation source."
Yes, WAAS GPS (TSO-C146) allows filing at MOCA altitudes since 2017. MOCA provides terrain clearance, and WAAS GPS guarantees navigation reception without requiring conventional navaid coverage. This is useful when MEA altitudes are high due to VOR reception requirements. For example, if MEA is 14,500 feet but MOCA is 9,600 feet, you can legally file at 10,000 feet with WAAS GPS—assuming no GPS or WAAS outages affect your route.
No, most general aviation GPS units including the G1000, GTN750, and GNS530W cannot fly RF (Radius-to-Fix) legs. RF approaches are designated as RNAV (RNP) and require specialized equipment typically found only in airline and business jet avionics. If the approach chart shows "RNAV (RNP)" in the title, verify your AFM specifically authorizes RF procedures—if RF is not listed in your limitations section, you cannot fly that approach.
Ready to Master GPS Approaches?
Practice LPV approaches and RNAV procedures in our G1000 NXi simulator with airline pilot instructors in Manhattan.
Continue Your IFR Training
Related programs and resources for instrument pilots
Instrument Rating Training Guide
Complete guide to earning your instrument rating in NYC — curriculum, requirements, and training timeline.
IFR Currency Training
Maintain instrument currency with structured simulator sessions — six approaches, holds, and tracking.
Professional Pilot IFR Prep
Advanced IFR training for airline interviews and ATP checkrides — SID/STAR procedures and CRM.
Business Jet IFR Transition
Single-pilot jet IFR procedures — high-altitude operations, automation management, and crew concepts.
Rusty Pilot Training
Rebuild IFR confidence safely after a break from flying — structured refresher with airline pilot instructors.
FAA WINGS LOFT Scenarios
Line Oriented Flight Training with FAA WINGS credit — real-world IFR scenarios from airline training.