Business aircraft flight crews and mission planning specialists are reporting frequent incidents of GPS jamming or spoofing interference during international trips, especially in the Middle East. Mitigating these incidents first means being able to identify them as soon as they occur.
“Spoofing or jamming simply refers to the GPS receiving counterfeit signals, and, because they look like real signals, the equipment is going to accept them,” said Simon Innocent, senior director of offering management for Honeywell’s commercial navigation systems. “GPS signals are relatively weak, so it’s rather easy to overpower them with stronger, ground-based signals.”
Capt. Daniel Galvin, senior captain and safety and standards captain for MP Air, a Part 91 operator that frequently flies missions to the Middle East, said he’s been spoofed six or eight times during recent trips to the region. “What was unusual, was that I went there and back early in February and didn’t get spoofed. That was probably the first time in the last 18 months that it didn’t happen.”
As their experience dealing with GPS interference increases, Galvin said his colleagues are becoming much more aware of the threat and what they can do to stay ahead of the problem. “We always follow our OEM recommended procedures, and we recommend having the RMI [radio magnetic indicator] pulled up with a ground-based navigation source, just for checking,” said Galvin. “We can start to see things happening on the displays.”
Signs of Possible GPS Interference
Honeywell’s Innocent explained that pilots can see several things to alert them that GPS has been compromised. He said the most likely clue is a quick position shift.
“We’ve seen jumps of 50 miles to several hundred miles in a GPS location,” Galvin said. “Also, depending on how the aircraft is equipped, you can also have CAS messages pop up to show discrepancies between the GPS and other NAV sources like the IRS [inertial reference system],” he said. “And since modern avionics are all integrated, GPS spoofing can impact the performance of anything that gets data from the receiver.”
“Some modern avionics are going to have greater resistance to spoofing, however, it will still have some impact on the system’s performance,” Innocent said. “We have some additional software updates coming that will further help increase the GPS system’s ability to better detect and mitigate spoofing.”
“We tell our pilots not to totally focus on what they expect to see but look at other ways spoofing can manifest in ways you are not expecting,” Galvin said. “If you go in with the mindset that ‘this or that’ will happen, you may miss something else that can impact your flight.”
Using Handheld GPS Units
Flight crews in Galvin’s fleet use simple handheld GPS units on the glareshield to provide input to the iPads they use for oceanic navigation. So far, spoofing has had no impact on the handheld units’ performance.
“The aircraft’s GPS made a sudden big jump in our position, but the iPad stayed dead on track through it all,” Galvin said. “I have no idea why the handheld didn’t get spoofed.”
More than the 200-mile changes of location associated with GPS interference, what worries Galvin are much smaller, incremental shifts.
“If you have an instance where it moved a half mile, and then 10 minutes later, it moved another half mile or so, it’s easy to miss small changes,” said Galvin. “That’s the insidious aspect of the problem because you could easily overlook it if you’re focused on another part of the flight. A mile is a substantial error during an approach.”
Experts also advise operators to include GPS interference incidents in their SMS. “If you do run into a GPS spoofing situation, make sure that once you’ve completed your flight, you actually record it and log it so that the rest of the operation will find out how you dealt with it,” said Clèment Meersseman, vice president, strategic partnerships at Nimbl, during an expert panel at February’s 2025 NBAA International Operators Conference, in San Juan, PR.
Power-Cycle and Reset Your Systems
Another common misconception is that systems affected by GPS spoofing or jamming will return to normal once the aircraft exits the zone of interreference. “In many cases with older units, the GPS failure will remain active even when the aircraft leaves the area of spoofing and remains ‘stuck’ and unusable until it can be power-cycled and reset,” said Innocent. “We’ve heard that some OEMs have created specific recommendations for those situations. But we don’t see that issue with modern GPS receivers.”
Either way, Galvin said his company’s standard operating procedure in any post-spoofing situation is to use only non-GPS navigational aids until they can confirm that the aircraft’s systems are “spoof free.”
As soon as possible, pilots should notify air traffic control that they’ve “been spoofed,” said Galvin, so controllers can pay closer attention to the aircraft’s exact location and tracking. “Communications is especially critical in the Middle East, but also when flying east to west over the North Atlantic,” he said.
If Galvin encounters interference while leaving the Middle East enroute to New York, for example, he reports the incident to oceanic during his initial call because it may affect required navigational performance. “We may not get the altitude and routing we need, and we will possibly get stuck at a lower altitude and range may be compromised,” Galvin said. “You need to plan that well in advance.”
International Business Aviation Council Ltd.