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A C421 pilot encounters icing within his pitot static system which develops into an emergency situation with radar vectoring accomplished to VFR conditions for landing at pao, ca.
| Attributes | |
| ACN | 453864 |
| Time | |
| Date | 199911 |
| Day | Sun |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : zoa.artcc |
| State Reference | CA |
| Altitude | msl bound lower : 2500 msl bound upper : 5000 |
| Environment | |
| Flight Conditions | IMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zoa.artcc tracon : o90.tracon |
| Operator | general aviation : personal |
| Make Model Name | Golden Eagle 421 |
| Operating Under FAR Part | Part 91 |
| Navigation In Use | other |
| Flight Phase | descent : vacating altitude |
| Route In Use | approach : visual arrival : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | other |
| Function | flight crew : single pilot |
| Qualification | pilot : multi engine pilot : commercial pilot : cfi pilot : atp pilot : instrument |
| Experience | flight time last 90 days : 125 flight time total : 3525 flight time type : 200 |
| ASRS Report | 453864 |
| Person 2 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Events | |
| Anomaly | aircraft equipment problem : critical altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other other spatial deviation |
| Independent Detector | other flight crewa |
| Resolutory Action | controller : issued new clearance controller : provided flight assist flight crew : declared emergency flight crew : diverted to another airport |
| Consequence | faa : reviewed incident with flight crew other |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance Environmental Factor Weather Aircraft |
| Primary Problem | Aircraft |
| Air Traffic Incident | Pilot Deviation |
Narrative:
Due to erratic pitot static performance (instruments froze and surged erratically). I had deviations from assigned altitude (in excess of 1000 ft). I noticed on attempted descent from 5000 ft to 4000 ft near pye that altimeter was inoperative and airspeed erroneous. Pitot static heaters were on. I switched to alternate. Static position, airspeed and altimeter temporarily ok, froze again. Asked for assistance with altitude and ground speed from ATC while flying plane, troubleshooting. Crosschecked with copilot's instruments. Not reliable when system was erroneous -- kept switching from normal to alternate static position. Problematic reliability. With help of ATC and GPS for speed and situational awareness was vectored to VFR conditions at pao.
Original NASA ASRS Text
Title: A C421 PLT ENCOUNTERS ICING WITHIN HIS PITOT STATIC SYS WHICH DEVELOPS INTO AN EMER SIT WITH RADAR VECTORING ACCOMPLISHED TO VFR CONDITIONS FOR LNDG AT PAO, CA.
Narrative: DUE TO ERRATIC PITOT STATIC PERFORMANCE (INSTS FROZE AND SURGED ERRATICALLY). I HAD DEVS FROM ASSIGNED ALT (IN EXCESS OF 1000 FT). I NOTICED ON ATTEMPTED DSCNT FROM 5000 FT TO 4000 FT NEAR PYE THAT ALTIMETER WAS INOP AND AIRSPD ERRONEOUS. PITOT STATIC HEATERS WERE ON. I SWITCHED TO ALTERNATE. STATIC POS, AIRSPD AND ALTIMETER TEMPORARILY OK, FROZE AGAIN. ASKED FOR ASSISTANCE WITH ALT AND GND SPD FROM ATC WHILE FLYING PLANE, TROUBLESHOOTING. XCHKED WITH COPLT'S INSTS. NOT RELIABLE WHEN SYS WAS ERRONEOUS -- KEPT SWITCHING FROM NORMAL TO ALTERNATE STATIC POS. PROBLEMATIC RELIABILITY. WITH HELP OF ATC AND GPS FOR SPD AND SITUATIONAL AWARENESS WAS VECTORED TO VFR CONDITIONS AT PAO.
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.