Narrative:

I am recently based at capodichino airport, naples, italy, flying lear 35's. Between the dates of nov/xa/99 and dec/xb/99, I consistently lost GPS navigation function when returning to naples. When approaching from the north, this loss occurs southeast of the teano VOR (tea) to the interception of the runway 24 localizer, bento intersection, and to about pomigliano VOR (pom). When approaching from the south, this occurs between the sorrento VOR (sor), and the galti, ektol, and bento intersections, and then along the runway 24 localizer to the area of the pomilgliano VOR (pom). This occurs in two different aircraft, both lear 35's, using two types of GPS receivers, both IFR approved for enroute and non-precision approaches. These area trimble and apollo receivers. I suspect that harmonic signals from italian tv transmitters are the cause of this loss of GPS. This loss typically occurs when using the GPS to position the aircraft for the ILS runway 24 approach to naples. This then requires a request for vectors from naples approach when the loss occurs. This situation should be notamed and mentioned on both the DOD and commercial charts, and the appropriate FLIP supplement. Callback conversation with reporter revealed the following information: reporter confirmed that their lear 35 aircraft (3) are experiencing the GPS navigation function loss. This loss occurs only at the naples airport and only at altitudes below 15000 ft as they approach the airport. They have no problem on departure since they're not using the GPS to navigate. Reporter believes the tv transmitters are causing the problem because the italian tv transmitters operate at a frequency 2 to 3 higher than they do in the united states.

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Original NASA ASRS Text

Title: A LEAR 35 PLT RPTS LOSS OF GPS NAV NEAR NAPLES, ITALY.

Narrative: I AM RECENTLY BASED AT CAPODICHINO ARPT, NAPLES, ITALY, FLYING LEAR 35'S. BETWEEN THE DATES OF NOV/XA/99 AND DEC/XB/99, I CONSISTENTLY LOST GPS NAV FUNCTION WHEN RETURNING TO NAPLES. WHEN APPROACHING FROM THE N, THIS LOSS OCCURS SE OF THE TEANO VOR (TEA) TO THE INTERCEPTION OF THE RWY 24 LOC, BENTO INTERSECTION, AND TO ABOUT POMIGLIANO VOR (POM). WHEN APPROACHING FROM THE S, THIS OCCURS BETWEEN THE SORRENTO VOR (SOR), AND THE GALTI, EKTOL, AND BENTO INTERSECTIONS, AND THEN ALONG THE RWY 24 LOC TO THE AREA OF THE POMILGLIANO VOR (POM). THIS OCCURS IN TWO DIFFERENT ACFT, BOTH LEAR 35'S, USING TWO TYPES OF GPS RECEIVERS, BOTH IFR APPROVED FOR ENROUTE AND NON-PRECISION APPROACHES. THESE AREA TRIMBLE AND APOLLO RECEIVERS. I SUSPECT THAT HARMONIC SIGNALS FROM ITALIAN TV TRANSMITTERS ARE THE CAUSE OF THIS LOSS OF GPS. THIS LOSS TYPICALLY OCCURS WHEN USING THE GPS TO POS THE ACFT FOR THE ILS RWY 24 APCH TO NAPLES. THIS THEN REQUIRES A REQUEST FOR VECTORS FROM NAPLES APCH WHEN THE LOSS OCCURS. THIS SIT SHOULD BE NOTAMED AND MENTIONED ON BOTH THE DOD AND COMMERCIAL CHARTS, AND THE APPROPRIATE FLIP SUPPLEMENT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR CONFIRMED THAT THEIR LEAR 35 ACFT (3) ARE EXPERIENCING THE GPS NAV FUNCTION LOSS. THIS LOSS OCCURS ONLY AT THE NAPLES ARPT AND ONLY AT ALTS BELOW 15000 FT AS THEY APCH THE ARPT. THEY HAVE NO PROB ON DEP SINCE THEY'RE NOT USING THE GPS TO NAVIGATE. RPTR BELIEVES THE TV TRANSMITTERS ARE CAUSING THE PROB BECAUSE THE ITALIAN TV TRANSMITTERS OPERATE AT A FREQ 2 TO 3 HIGHER THAN THEY DO IN THE UNITED STATES.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.