What About Portable GPS?
I was flying along the other day when the controller called a Bonanza pilot on the frequency. “I see that you have filed a slant uniform but do you have some sort of GPS or something you could use to fly direct to XYZ?” the controller asked.
The controller had acknowledged that the Bonanza did not have an IFR approved RNAV system onboard or the pilot would not have filed slant uniform as the equipment suffix. But the controller, trying to be helpful, was dropping the biggest hint that it would be okay for the Bonanza pilot to accept a direct en route clearance if he had some sort of navigator.
I was hoping the Bonanza pilot would understand the situation, say thanks, and head off direct to his destination. But instead he launched into a long description of the portable navigation system—complete with detailed moving map display—he had in the cockpit.
The controller tired again by repeating the clearance offer of direct to the destination. But the pilot of the Bonanza declined saying “my portable system is not IFR approved.”
By now I’m sure the controller was chomping big chunks out of his tongue as he told the Bonanza pilot to “fly heading 000 until receiving XYZ.”
What we had were two people trying their best to be helpful. The controller wanted to help the Bonanza pilot shave a few miles off of his trip, and the Bonanza pilot was determined to remain within the regulations as he understood them.
The reality is that controllers know pilots are flying around with all sorts of portable navigation devices, many of them with accuracy and capability equal to, or even beyond certified systems. Portable systems can show satellite weather, moving maps with all airway, VOR and airport information, and some even have terrain warning built in. There are mounting devices for the popular portable systems that allow a pilot to “plug them in” so they function very much like avionics that are permanently installed.
For en route navigation portable GPS systems provide all the accuracy, precision and reliability that we need, and controllers know it. That’s why they routinely offer direct clearances even if the equipment suffix letter the pilot filed with his flight plan does not show RNAV capability.
For controllers issuing a direct clearance to an airplane in radar contact is really the same as issuing a heading to fly. That’s why you’ll often have a controller ask you for the heading to your destination, or to another point along your route. You read back the heading from your navigator—certified or otherwise—and he clears you to fly that heading. Everybody is happy and no rules are broken or even bent.
Using a non-approved navigation system to fly an IFR approach is another matter, even though many portable GPS units store approach procedures, and even approach charts, in their data bases. An instrument approach takes us close to terrain and obstructions and the precision of a navigation system needs to have been demonstrated before relying on it to miss the ground by only a few hundred feet.
Navigating en route where terrain clearance at approved altitudes is large has none of the risks of flying an approach. And en route separation for airplanes flying direct is provided by radar, not precise flying of a published route so small deviations from a true direct path do not compromise lateral separation.
Pilots, like the one I overheard in the Bonanza, are worried that somebody is going to bust them for accepting a direct en route clearance while using an unapproved navigator.. They shouldn’t. The controllers know how things work, they’re not out to get us, they just want to be helpful and keep traffic flowing smoothly.
The only rule the Bonanza pilot could have broken in this situation is to have filed an equipment suffix indicating that he had approved equipment that wasn’t there. That is a particularly grievous offense when it comes to RVSM, and the FAA has cracked down on pilots who either indicate they have RVSM certification on their flight plan, or accept a clearance into RVSM airspace without having the certification and without telling the controller.
Unlike a direct clearance that involves wide lateral separation from other IFR aircraft, flying in RVSM airspace offers only 1,000 foot vertical separation, and that’s not much room for error at high altitudes where altimeter errors in non-approved systems are more likely.
An important issue for FltPlan.com users is to go into your aircraft profile and update the equipment list if something changes, particularly if your approval for RVSM changes. If you don’t keep your aircraft profile up to date you could be telling the FAA lies that it really does care about. It’s best to enter the correct equipment using the “A/C ICAO DATA” button that is on the bottom left side of the FltPlan.com main menu screen. Simply click on every type of approved equipment you have onboard and FltPlan.com will automatically translate that to the proper ICAO equipment designations to file each time with your flight plan.
If you have been accurate in filing your flight plan and the controller offers a direct en route clearance, take it.