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A BE35 pilot attributed an early descent on an ILS approach to a lack of training in the use of a panel mounted GPS unit with complex functionality.
| Attributes | |
| ACN | 682572 |
| Time | |
| Date | 200512 |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | intersection : footo |
| State Reference | CA |
| Altitude | msl single value : 3300 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : nct.tracon |
| Operator | general aviation : personal |
| Make Model Name | Bonanza 35 |
| Operating Under FAR Part | Part 91 |
| Navigation In Use | ils localizer & glide slope : 25r |
| Flight Phase | descent : approach |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | other |
| Function | flight crew : single pilot |
| Qualification | pilot : instrument pilot : private |
| Experience | flight time last 90 days : 50 flight time total : 600 flight time type : 250 |
| ASRS Report | 682572 |
| Person 2 | |
| Affiliation | government : faa |
| Function | controller : approach |
| Events | |
| Anomaly | altitude deviation : crossing restriction not met altitude deviation : excursion from assigned altitude non adherence : published procedure non adherence : clearance non adherence : far |
| Resolutory Action | flight crew : returned to assigned altitude flight crew : became reoriented |
| Consequence | faa : reviewed incident with flight crew |
| Supplementary | |
| Problem Areas | Chart Or Publication Flight Crew Human Performance |
| Primary Problem | Flight Crew Human Performance |
Narrative:
While being vectored to the ILS runway 25R approach into lvk; I set up the 'vectors to final' function in my garmin GPS 530. Rather than manually selecting the navigation frequency for the localizer; I relied upon the 530 to automatic switch to the frequency; which it failed to do. I switched from 'GPS' mode to 'vloc' mode as I intercepted the localizer; and failed to notice the 'fail' flags on the CDI. Accordingly; I began my descent prematurely; violating the ATC instruction to maintain 3300 ft until footo. A contributing factor was my failure to positively identify footo before descending through 3300 ft. This resulted; in part; from the fact that the GPS 530 drops most intxns other than the FAF when you are on active vtf (vectors to final) mode.callback conversation with reporter revealed the following information: reporter stated that he received zero training with his system prior to flying with it. He would recommend as a minimum; a check out with a CFI who would presumably run a pilot through the equipment's paces. He commutes to a large metropolitan airport and uses his aircraft's dual GPS systems to reduce the workload tremendously. During this particular incident; he was VMC and when he started his descent; approach control called immediately wanting to know what he was doing. There was no further discussion after he climbed back to 3300 ft.
Original NASA ASRS Text
Title: A BE35 PLT ATTRIBUTED AN EARLY DESCENT ON AN ILS APPROACH TO A LACK OF TRAINING IN THE USE OF A PANEL MOUNTED GPS UNIT WITH COMPLEX FUNCTIONALITY.
Narrative: WHILE BEING VECTORED TO THE ILS RWY 25R APCH INTO LVK; I SET UP THE 'VECTORS TO FINAL' FUNCTION IN MY GARMIN GPS 530. RATHER THAN MANUALLY SELECTING THE NAV FREQ FOR THE LOCALIZER; I RELIED UPON THE 530 TO AUTO SWITCH TO THE FREQ; WHICH IT FAILED TO DO. I SWITCHED FROM 'GPS' MODE TO 'VLOC' MODE AS I INTERCEPTED THE LOCALIZER; AND FAILED TO NOTICE THE 'FAIL' FLAGS ON THE CDI. ACCORDINGLY; I BEGAN MY DSCNT PREMATURELY; VIOLATING THE ATC INSTRUCTION TO MAINTAIN 3300 FT UNTIL FOOTO. A CONTRIBUTING FACTOR WAS MY FAILURE TO POSITIVELY IDENTIFY FOOTO BEFORE DSNDING THROUGH 3300 FT. THIS RESULTED; IN PART; FROM THE FACT THAT THE GPS 530 DROPS MOST INTXNS OTHER THAN THE FAF WHEN YOU ARE ON ACTIVE VTF (VECTORS TO FINAL) MODE.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT HE RECEIVED ZERO TRAINING WITH HIS SYSTEM PRIOR TO FLYING WITH IT. HE WOULD RECOMMEND AS A MINIMUM; A CHK OUT WITH A CFI WHO WOULD PRESUMABLY RUN A PLT THROUGH THE EQUIP'S PACES. HE COMMUTES TO A LARGE METROPOLITAN ARPT AND USES HIS ACFT'S DUAL GPS SYSTEMS TO REDUCE THE WORKLOAD TREMENDOUSLY. DURING THIS PARTICULAR INCIDENT; HE WAS VMC AND WHEN HE STARTED HIS DSCNT; APCH CTL CALLED IMMEDIATELY WANTING TO KNOW WHAT HE WAS DOING. THERE WAS NO FURTHER DISCUSSION AFTER HE CLBED BACK TO 3300 FT.
Data retrieved from NASA's ASRS site as of January 2009 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.