 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
A BE9L pilot, making a GPS approach to pao, broke out one quarter mi to the right of the runway centerline.
| Attributes | |
| ACN | 543239 |
| Time | |
| Date | 200204 |
| Day | Mon |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : pao.airport |
| State Reference | CA |
| Altitude | agl single value : 1500 |
| Environment | |
| Flight Conditions | IMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : o90.tracon tower : pao.tower |
| Operator | general aviation : personal |
| Make Model Name | King Air C90 E90 |
| Operating Under FAR Part | Part 91 |
| Navigation In Use | other |
| Flight Phase | descent : approach |
| Route In Use | approach : instrument non precision |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | other |
| Function | flight crew : single pilot |
| Qualification | pilot : commercial pilot : multi engine pilot : instrument |
| Experience | flight time last 90 days : 55 flight time total : 1040 flight time type : 185 |
| ASRS Report | 543239 |
| Person 2 | |
| Affiliation | government : faa |
| Function | controller : approach |
| Events | |
| Anomaly | aircraft equipment problem : critical non adherence : published procedure other anomaly other other spatial deviation |
| Independent Detector | other flight crewa |
| Resolutory Action | none taken : detected after the fact other |
| Consequence | other |
| Supplementary | |
| Problem Areas | Aircraft Flight Crew Human Performance |
| Primary Problem | Flight Crew Human Performance |
Narrative:
While being vectored for the final approach heading, raim was momentarily lost for the GPS approach into palo alto. Before I could notify ATC the raim was apparently restored. I was unaware that the approach mode did not return to 'active,' thereby increasing the CDI sensitivity needed to make an accurate approach. I continued the approach and broke out at 1500 ft to discover I was 1/4 mi to the right of runway centerline. I canceled IFR and went around the traffic pattern to land. 1/4 mi would appear acceptable needle deflection in an 'armed' approach CDI mode. I have contacted an avionics shop regarding the temporary 'lost raim.' they explained that it happens from time to time. This experience shows that the armed/active annunciator must be included in the instrument approach scan throughout the procedure.
Original NASA ASRS Text
Title: A BE9L PLT, MAKING A GPS APCH TO PAO, BROKE OUT ONE QUARTER MI TO THE R OF THE RWY CTRLINE.
Narrative: WHILE BEING VECTORED FOR THE FINAL APCH HEADING, RAIM WAS MOMENTARILY LOST FOR THE GPS APCH INTO PALO ALTO. BEFORE I COULD NOTIFY ATC THE RAIM WAS APPARENTLY RESTORED. I WAS UNAWARE THAT THE APCH MODE DID NOT RETURN TO 'ACTIVE,' THEREBY INCREASING THE CDI SENSITIVITY NEEDED TO MAKE AN ACCURATE APCH. I CONTINUED THE APCH AND BROKE OUT AT 1500 FT TO DISCOVER I WAS 1/4 MI TO THE R OF RWY CTRLINE. I CANCELED IFR AND WENT AROUND THE TFC PATTERN TO LAND. 1/4 MI WOULD APPEAR ACCEPTABLE NEEDLE DEFLECTION IN AN 'ARMED' APCH CDI MODE. I HAVE CONTACTED AN AVIONICS SHOP REGARDING THE TEMPORARY 'LOST RAIM.' THEY EXPLAINED THAT IT HAPPENS FROM TIME TO TIME. THIS EXPERIENCE SHOWS THAT THE ARMED/ACTIVE ANNUNCIATOR MUST BE INCLUDED IN THE INST APCH SCAN THROUGHOUT THE PROC.
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.