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C170 pilot using handheld GPS enters class C airspace without 2-WAY communication. GPS malfunction.
| Attributes | |
| ACN | 350676 |
| Time | |
| Date | 199610 |
| Day | Sat |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : ont |
| State Reference | CA |
| Altitude | msl bound lower : 2500 msl bound upper : 2500 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : ont |
| Operator | general aviation : personal |
| Make Model Name | Cessna 170 |
| Operating Under FAR Part | Part 91 |
| Flight Phase | cruise other |
| Flight Plan | None |
| Person 1 | |
| Affiliation | Other |
| Function | flight crew : single pilot |
| Qualification | pilot : private |
| Experience | flight time last 90 days : 20 flight time total : 400 flight time type : 400 |
| ASRS Report | 350676 |
| Events | |
| Anomaly | other anomaly other other anomaly other |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : exited adverse environment |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Navigational Facility |
| Air Traffic Incident | Pilot Deviation other |
Narrative:
Flying VFR from ral to ccb, using apollo precedus handheld GPS for navigational reference. Cruise en route, position and status seemed fine. VFR conditions, visibility reported 10 mi. Continuation of flight from ral to ccb, a 'big airport' seemed to get closer and closer according to GPS position, is still out of ontario class C. From a visual standpoint, position was definitely in class C airspace, did an immediate right turn and flew visually to ccb. When airplane landed, GPS indicated location was burbank. Turned off GPS, then back on, position now at ccb. Called apollo, spoke to technician. They had received numerous calls about erroneous position, said a new satellite was put in orbit and moved position of some satellites without any notification, therefore my GPS didn't have the right almanac. He said there were a total of 26 satellites, mine showed 25. He suggested to leave GPS on for 45 mins to acquire new almanac. Left GPS on, now shows a total of 26 satellites. GPS position seem correct. I didn't see any NOTAM about GPS. I would definitely like to know if this is an apollo problem or did this affect other manufacturers of GPS. Conclusion: use handheld GPS as a reference only -- doesn't have receiver autonomous integrity monitor. Callback conversation with reporter revealed the following information: reporter states that there have been no further problems with his handheld GPS nor has he heard of others with problems. The technician with whom he spoke said he had been out hiking and using his handheld GPS and it was indicating a wrong position. He later discovered it was from the same problem as reporter, the GPS had not updated its almanac with the new satellite and so was giving erroneous information. The GPS prioritizes with first position information, then update of the almanac, thus the wrong position at times. The company fallback is that the handheld was not designed as a primary navigation instrument and should never be used as such. Reporter feels the company ought to develop some way to let the public know of new satellites and the need for an update on the almanac.
Original NASA ASRS Text
Title: C170 PLT USING HANDHELD GPS ENTERS CLASS C AIRSPACE WITHOUT 2-WAY COM. GPS MALFUNCTION.
Narrative: FLYING VFR FROM RAL TO CCB, USING APOLLO PRECEDUS HANDHELD GPS FOR NAVIGATIONAL REF. CRUISE ENRTE, POS AND STATUS SEEMED FINE. VFR CONDITIONS, VISIBILITY RPTED 10 MI. CONTINUATION OF FLT FROM RAL TO CCB, A 'BIG ARPT' SEEMED TO GET CLOSER AND CLOSER ACCORDING TO GPS POS, IS STILL OUT OF ONTARIO CLASS C. FROM A VISUAL STANDPOINT, POS WAS DEFINITELY IN CLASS C AIRSPACE, DID AN IMMEDIATE R TURN AND FLEW VISUALLY TO CCB. WHEN AIRPLANE LANDED, GPS INDICATED LOCATION WAS BURBANK. TURNED OFF GPS, THEN BACK ON, POS NOW AT CCB. CALLED APOLLO, SPOKE TO TECHNICIAN. THEY HAD RECEIVED NUMEROUS CALLS ABOUT ERRONEOUS POS, SAID A NEW SATELLITE WAS PUT IN ORBIT AND MOVED POS OF SOME SATELLITES WITHOUT ANY NOTIFICATION, THEREFORE MY GPS DIDN'T HAVE THE RIGHT ALMANAC. HE SAID THERE WERE A TOTAL OF 26 SATELLITES, MINE SHOWED 25. HE SUGGESTED TO LEAVE GPS ON FOR 45 MINS TO ACQUIRE NEW ALMANAC. LEFT GPS ON, NOW SHOWS A TOTAL OF 26 SATELLITES. GPS POS SEEM CORRECT. I DIDN'T SEE ANY NOTAM ABOUT GPS. I WOULD DEFINITELY LIKE TO KNOW IF THIS IS AN APOLLO PROB OR DID THIS AFFECT OTHER MANUFACTURERS OF GPS. CONCLUSION: USE HANDHELD GPS AS A REF ONLY -- DOESN'T HAVE RECEIVER AUTONOMOUS INTEGRITY MONITOR. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES THAT THERE HAVE BEEN NO FURTHER PROBS WITH HIS HANDHELD GPS NOR HAS HE HEARD OF OTHERS WITH PROBS. THE TECHNICIAN WITH WHOM HE SPOKE SAID HE HAD BEEN OUT HIKING AND USING HIS HANDHELD GPS AND IT WAS INDICATING A WRONG POS. HE LATER DISCOVERED IT WAS FROM THE SAME PROB AS RPTR, THE GPS HAD NOT UPDATED ITS ALMANAC WITH THE NEW SATELLITE AND SO WAS GIVING ERRONEOUS INFO. THE GPS PRIORITIZES WITH FIRST POS INFO, THEN UPDATE OF THE ALMANAC, THUS THE WRONG POS AT TIMES. THE COMPANY FALLBACK IS THAT THE HANDHELD WAS NOT DESIGNED AS A PRIMARY NAV INST AND SHOULD NEVER BE USED AS SUCH. RPTR FEELS THE COMPANY OUGHT TO DEVELOP SOME WAY TO LET THE PUBLIC KNOW OF NEW SATELLITES AND THE NEED FOR AN UPDATE ON THE ALMANAC.
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.