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Pilot experiences an altitude deviation due in part to distraction with unfamiliar GPS navigation system.
| Attributes | |
| ACN | 717452 |
| Time | |
| Date | 200611 |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : zzz.airport |
| State Reference | US |
| Altitude | msl single value : 1400 |
| Environment | |
| Flight Conditions | VMC |
| Weather Elements | Fog |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | tracon : zzz.tracon tower : fxe.tower |
| Operator | general aviation : corporate |
| Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
| Operating Under FAR Part | Part 91 |
| Navigation In Use | other |
| Flight Phase | descent : approach |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : corporate |
| Function | flight crew : single pilot |
| Qualification | pilot : commercial |
| Experience | flight time last 90 days : 70 flight time total : 3200 flight time type : 300 |
| ASRS Report | 717452 |
| Person 2 | |
| Affiliation | government : faa |
| Function | controller : approach |
| Events | |
| Anomaly | aircraft equipment problem : less severe altitude deviation : overshoot non adherence : clearance other spatial deviation |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued advisory flight crew : returned to assigned altitude |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance Aircraft |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
I was on an IFR clearance; but in VMC above the fog layer. While on vectors for the ILS; I was instructed by approach to descend from 3000 ft MSL to 1800 ft MSL. I was attempting to correctly load and activate the approach into the aircraft's new GPS unit (GNS 430); which I am not yet fully proficient with; and inadvertently descended below the assigned altitude. I had just begun to enter the fog layer when ATC advised I was at 1400 ft MSL versus assigned altitude of 1800 ft MSL. I immediately climbed back to assigned altitude and thanked the controller for catching the error. I continued the approach without further incident. Contributing factors: unfamiliar approach; increased cabin workload due to lack of proficiency with new navigation equipment; and reduced diligence of instrument scan while operating 'on top' in VMC; resulted in failure to arrest descent at assigned altitude. Lessons learned: practice! Take advantage of every opportunity to practice with new equipment in VFR conditions to achieve proficiency required to operate it fluently in the IFR environment. Additionally; maintain a diligent instrument scan; even when operating in visual conditions. Finally; at that altitude over level terrain; I could have more effectively used my radar altimeter warning bug as a tool for trapping errors like this.
Original NASA ASRS Text
Title: PLT EXPERIENCES AN ALTDEV DUE IN PART TO DISTR WITH UNFAMILIAR GPS NAV SYS.
Narrative: I WAS ON AN IFR CLRNC; BUT IN VMC ABOVE THE FOG LAYER. WHILE ON VECTORS FOR THE ILS; I WAS INSTRUCTED BY APCH TO DSND FROM 3000 FT MSL TO 1800 FT MSL. I WAS ATTEMPTING TO CORRECTLY LOAD AND ACTIVATE THE APCH INTO THE ACFT'S NEW GPS UNIT (GNS 430); WHICH I AM NOT YET FULLY PROFICIENT WITH; AND INADVERTENTLY DSNDED BELOW THE ASSIGNED ALT. I HAD JUST BEGUN TO ENTER THE FOG LAYER WHEN ATC ADVISED I WAS AT 1400 FT MSL VERSUS ASSIGNED ALT OF 1800 FT MSL. I IMMEDIATELY CLBED BACK TO ASSIGNED ALT AND THANKED THE CTLR FOR CATCHING THE ERROR. I CONTINUED THE APCH WITHOUT FURTHER INCIDENT. CONTRIBUTING FACTORS: UNFAMILIAR APCH; INCREASED CABIN WORKLOAD DUE TO LACK OF PROFICIENCY WITH NEW NAV EQUIP; AND REDUCED DILIGENCE OF INST SCAN WHILE OPERATING 'ON TOP' IN VMC; RESULTED IN FAILURE TO ARREST DSCNT AT ASSIGNED ALT. LESSONS LEARNED: PRACTICE! TAKE ADVANTAGE OF EVERY OPPORTUNITY TO PRACTICE WITH NEW EQUIP IN VFR CONDITIONS TO ACHIEVE PROFICIENCY REQUIRED TO OPERATE IT FLUENTLY IN THE IFR ENVIRONMENT. ADDITIONALLY; MAINTAIN A DILIGENT INST SCAN; EVEN WHEN OPERATING IN VISUAL CONDITIONS. FINALLY; AT THAT ALT OVER LEVEL TERRAIN; I COULD HAVE MORE EFFECTIVELY USED MY RADAR ALTIMETER WARNING BUG AS A TOOL FOR TRAPPING ERRORS LIKE THIS.
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.