AC112 pilot report GPS failure during GPS 04 approach to skx in poor visibility. A missed approach i...

Narrative:

1. AWOS at skx was inoperative. After receiving ATC clearance for the GPS 04 approach into skx; I announced my IFR approach to runway 04 on unicom. A pilot in the area said he was VFR at 500 ft over the rio grand gorge; with excellent visibility; but a snow cell was approaching with possible poor visibility. The pilot said his presence would not pose a problem for my IFR approach.2. I conducted the approach with a garmin GPS. During the approach; I had ground contact with limited forward visibility.3. My garmin 430 malfunctioned at about 1;200 AGL and about 4 miles from the airport. I could see the ground; but not the airport. I initiated a 'missed approach' by applying power; climbing; retracting my gear; and turning to the left 180 degrees.4. Called 'missed approach' on center frequency. ATC typically cannot hear below 10;000 to 11;000 MSL in that area (where I am familiar; from numerous flights every year). Another plane passing nearby confirmed our transmission and passed it on to ATC.5. Without a functional GPS; I was unable to locate the teloy intersection and hold there (which is part of the GPS 04 missed approach procedure).6. I maintained a heading of 220 degrees and climbed to 11;000 to rejoin V83 heading south (which I could identify on a separate VOR not attached to the garmin 430). 7. Around 11;000 I was able to speak with ATC. The connection was not good; and communications were not clear until I got further south. The controller questioned my not holding at teloy intersection for further instructions; I informed him about the failed GPS on approach. Eventually; after the situation was eventually clarified; the controller cleared me on V83 to santa fe airport; where I landed. 8. The GPS on the garmin 430 came back en route to santa fe airport; but the vos on the garmin 430 was inoperative. The next day I flew the plane from santa fe to skx and the garmin GPS again functioned normally; but the garmin vos remained inoperative. 9. Recently I had an additional electrical instrument installed; which -- along with humidity in the clouds -- may have produced this result. I will have this problem checked out.

Original NASA ASRS Text

Title: AC112 pilot report GPS failure during GPS 04 approach to SKX in poor visibility. A missed approach is initiated but the procedure cannot be complied with without the GPS. Communication is not possible with ATC below 11;000 which further added to the difficulties.

Narrative: 1. AWOS at SKX was inoperative. After receiving ATC clearance for the GPS 04 approach into SKX; I announced my IFR approach to Runway 04 on UNICOM. A pilot in the area said he was VFR at 500 FT over the Rio Grand Gorge; with excellent visibility; but a snow cell was approaching with possible poor visibility. The pilot said his presence would not pose a problem for my IFR approach.2. I conducted the approach with a Garmin GPS. During the approach; I had ground contact with limited forward visibility.3. My Garmin 430 malfunctioned at about 1;200 AGL and about 4 miles from the airport. I could see the ground; but not the airport. I initiated a 'missed approach' by applying power; climbing; retracting my gear; and turning to the left 180 degrees.4. Called 'missed approach' on center frequency. ATC typically cannot hear below 10;000 to 11;000 MSL in that area (where I am familiar; from numerous flights every year). Another plane passing nearby confirmed our transmission and passed it on to ATC.5. Without a functional GPS; I was unable to locate the TELOY Intersection and hold there (which is part of the GPS 04 missed approach procedure).6. I maintained a heading of 220 degrees and climbed to 11;000 to rejoin V83 heading south (which I could identify on a separate VOR not attached to the Garmin 430). 7. Around 11;000 I was able to speak with ATC. The connection was not good; and communications were not clear until I got further south. The Controller questioned my not holding at TELOY Intersection for further instructions; I informed him about the failed GPS on approach. Eventually; after the situation was eventually clarified; the Controller cleared me on V83 to Santa Fe airport; where I landed. 8. The GPS on the Garmin 430 came back en route to Santa Fe airport; but the VOS on the Garmin 430 was inoperative. The next day I flew the plane from Santa Fe to SKX and the Garmin GPS again functioned normally; but the Garmin VOS remained inoperative. 9. Recently I had an additional electrical instrument installed; which -- along with humidity in the clouds -- may have produced this result. I will have this problem checked out.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	931514
Time
Date	201102
Local Time Of Day	1201-1800
Place
Locale Reference	SKX.Airport
State Reference	NM
Environment
Flight Conditions	IMC
Aircraft 1
Make Model Name	Commander 112TC
Operating Under FAR Part	Part 91
Flight Phase	Landing
Flight Plan	IFR
Component
Aircraft Component	GPS & Other Satellite Navigation
Person 1
Function	Single Pilot
Qualification	Flight Crew Commercial
Experience	Flight Crew Last 90 Days 30 Flight Crew Total 5450 Flight Crew Type 5200
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Procedural Published Material / Policy Deviation - Track / Heading All Types

AC112 pilot report GPS failure during GPS 04 approach to skx in poor visibility. A missed approach is initiated but the procedure cannot be complied with without the GPS. Communication is not possible with ATC below 11;000 which further added to the difficulties.