A C182 pilot, on an ILS to sts, executed a missed approach, citing GS inaccuracy as the reason.

Attributes
ACN	535430
Time
Date	200201
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : sts.airport
State Reference	CA
Altitude	agl bound lower : 350 agl bound upper : 500
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zoa.artcc tower : sts.tower
Operator	general aviation : personal
Make Model Name	Skylane 182/RG Turbo Skylane/RG
Operating Under FAR Part	Part 91
Navigation In Use	ils localizer & glide slope : ns
Flight Phase	landing : missed approach
Route In Use	approach : instrument precision
Flight Plan	IFR
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : private pilot : instrument
Experience	flight time total : 1945
ASRS Report	535430
Person 2
Affiliation	government : faa
Function	controller : radar
Events
Anomaly	aircraft equipment problem : critical non adherence : published procedure other anomaly other anomaly other
Resolutory Action	controller : provided flight assist controller : issued advisory flight crew : became reoriented flight crew : executed missed approach
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Weather Airport Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

On jan/sun/02, the PIC was on a return flight from smx, ca, to home base sts, ca, under flight following with both ZLA and ZOA. The flight was uneventful until the PIC checked the terminal WX at sts and determined that the visibility was 2.5 mi and the ceiling was 400 ft AGL. Accordingly, after being passed off from bay approach to ZOA, the PIC requested an ILS approach into sts. While on the approach, it appeared everything was normal and the PIC proceeded on the localizer down the GS and as the approach was made to the airport, the runway or runway lighting, including approach lights did not come in view. The PIC had passed the airport, however, was in visual of the ground when he began the missed approach procedure and was advised by the tower to contact center. The PIC was advised that he was at 500 ft AGL when he passed over the runway even though the GS indicated that the aircraft was on the correct flight path. After the missed approach, the PIC requested an additional approach which was granted and on the second approach the runway was identified and a landing was made. As a follow-up, the PIC discussed the matter with both center and later with the tower manager and was told no further action would be taken. The PIC was concerned about the performance of the GS instrument and had it checked and subsequently adjusted to bring it into conformance with a set GS signal. Apparently the reason the first approach was high was due to the inaccuracy of the in plane instrument.

Original NASA ASRS Text

Title: A C182 PLT, ON AN ILS TO STS, EXECUTED A MISSED APCH, CITING GS INACCURACY AS THE REASON.

Narrative: ON JAN/SUN/02, THE PIC WAS ON A RETURN FLT FROM SMX, CA, TO HOME BASE STS, CA, UNDER FLT FOLLOWING WITH BOTH ZLA AND ZOA. THE FLT WAS UNEVENTFUL UNTIL THE PIC CHKED THE TERMINAL WX AT STS AND DETERMINED THAT THE VISIBILITY WAS 2.5 MI AND THE CEILING WAS 400 FT AGL. ACCORDINGLY, AFTER BEING PASSED OFF FROM BAY APCH TO ZOA, THE PIC REQUESTED AN ILS APCH INTO STS. WHILE ON THE APCH, IT APPEARED EVERYTHING WAS NORMAL AND THE PIC PROCEEDED ON THE LOC DOWN THE GS AND AS THE APCH WAS MADE TO THE ARPT, THE RWY OR RWY LIGHTING, INCLUDING APCH LIGHTS DID NOT COME IN VIEW. THE PIC HAD PASSED THE ARPT, HOWEVER, WAS IN VISUAL OF THE GND WHEN HE BEGAN THE MISSED APCH PROC AND WAS ADVISED BY THE TWR TO CONTACT CTR. THE PIC WAS ADVISED THAT HE WAS AT 500 FT AGL WHEN HE PASSED OVER THE RWY EVEN THOUGH THE GS INDICATED THAT THE ACFT WAS ON THE CORRECT FLT PATH. AFTER THE MISSED APCH, THE PIC REQUESTED AN ADDITIONAL APCH WHICH WAS GRANTED AND ON THE SECOND APCH THE RWY WAS IDENTIFIED AND A LNDG WAS MADE. AS A FOLLOW-UP, THE PIC DISCUSSED THE MATTER WITH BOTH CTR AND LATER WITH THE TWR MGR AND WAS TOLD NO FURTHER ACTION WOULD BE TAKEN. THE PIC WAS CONCERNED ABOUT THE PERFORMANCE OF THE GS INST AND HAD IT CHKED AND SUBSEQUENTLY ADJUSTED TO BRING IT INTO CONFORMANCE WITH A SET GS SIGNAL. APPARENTLY THE REASON THE FIRST APCH WAS HIGH WAS DUE TO THE INACCURACY OF THE IN PLANE INST.

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.