Pilot of a piper cherokee archer, PA28-181, experienced erratic indications from his hand-held GPS n...

Attributes
ACN	406134
Time
Date	199806
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : thx
State Reference	TX
Altitude	msl bound lower : 6500 msl bound upper : 7500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zhu
Operator	common carrier : air taxi
Make Model Name	PA-28 Cherokee/Archer II/Dakota/Pillan/Warrior
Operating Under FAR Part	Part 135
Flight Phase	cruise other
Flight Plan	VFR
Person 1
Affiliation	company : air taxi
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : commercial
ASRS Report	406134
Events
Anomaly	aircraft equipment problem : less severe other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	none taken : anomaly accepted none taken : unable
Consequence	Other
Supplementary
Air Traffic Incident	other

Narrative:

Every day this week I have had problems with GPS service between san antonio, mcallen, and laredo, tx. I am a part 135 air freight pilot and have used a garmin GPS 90 as a supplemental NAVAID for over a yr. The GPS usually works very well. This week and 1 or 2 days last week, the GPS has been unserviceable more than it works. I get error messages saying 'poor GPS coverage' or 'need 2- dimensional altitude information.' if the government is experimenting with GPS coverage in south texas, they are causing a real problem. Callback conversation with reporter revealed the following information: reporter stated that he has subsequently sent the GPS to the manufacturer for repair and that the problems he experienced were not caused by some type of government experimentation. He stated that it was a non IFR approved garmin model 90, and that the aircraft was equipped with 2 VOR receivers. He further stated that he was flying between 6500 ft and 7500 ft southwest of the three rivers VORTAC under the kingsville MOA and on top of a 3000 ft overcast with approximately 10 mi visibility.

Original NASA ASRS Text

Title: PLT OF A PIPER CHEROKEE ARCHER, PA28-181, EXPERIENCED ERRATIC INDICATIONS FROM HIS HAND-HELD GPS NAV EQUIP. IT HAD BEEN PROVIDING ACCURATE INFO FOR 6 MONTHS AND THEN STARTED SHOWING ERROR MESSAGES INDICATING POOR RECEPTION COVERAGE.

Narrative: EVERY DAY THIS WK I HAVE HAD PROBS WITH GPS SVC BTWN SAN ANTONIO, MCALLEN, AND LAREDO, TX. I AM A PART 135 AIR FREIGHT PLT AND HAVE USED A GARMIN GPS 90 AS A SUPPLEMENTAL NAVAID FOR OVER A YR. THE GPS USUALLY WORKS VERY WELL. THIS WK AND 1 OR 2 DAYS LAST WK, THE GPS HAS BEEN UNSERVICEABLE MORE THAN IT WORKS. I GET ERROR MESSAGES SAYING 'POOR GPS COVERAGE' OR 'NEED 2- DIMENSIONAL ALT INFO.' IF THE GOV IS EXPERIMENTING WITH GPS COVERAGE IN SOUTH TEXAS, THEY ARE CAUSING A REAL PROB. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT HE HAS SUBSEQUENTLY SENT THE GPS TO THE MANUFACTURER FOR REPAIR AND THAT THE PROBS HE EXPERIENCED WERE NOT CAUSED BY SOME TYPE OF GOV EXPERIMENTATION. HE STATED THAT IT WAS A NON IFR APPROVED GARMIN MODEL 90, AND THAT THE ACFT WAS EQUIPPED WITH 2 VOR RECEIVERS. HE FURTHER STATED THAT HE WAS FLYING BTWN 6500 FT AND 7500 FT SW OF THE THREE RIVERS VORTAC UNDER THE KINGSVILLE MOA AND ON TOP OF A 3000 FT OVCST WITH APPROX 10 MI VISIBILITY.

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.

Pilot of a piper cherokee archer, PA28-181, experienced erratic indications from his hand-held GPS navigation equipment. It had been providing accurate information for 6 months and then started showing error messages indicating poor reception coverage.