Part 135 atx frt small transport pilot initiates INS approachs with WX below minimums.

Attributes
ACN	156690
Time
Date	199009
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : sps
State Reference	TX
Altitude	agl bound lower : 200 agl bound upper : 200
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : sps tower : isp
Operator	common carrier : air taxi
Make Model Name	Small Transport, Low Wing, 2 Recip Eng
Flight Phase	descent : approach landing : missed approach other
Flight Plan	IFR
Person 1
Affiliation	company : air taxi
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : commercial pilot : cfi
Experience	flight time last 90 days : 125 flight time total : 1400 flight time type : 350
ASRS Report	156690
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	non adherence : far non adherence : published procedure
Independent Detector	other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I was en route to sps from dal. The WX was clear, but there was a 9 dew pt spread at sps. Arriving at sps I remember the wind was out of the south at 7 KTS, ceiling 300' obscured, fog. I do not remember hearing the visibility. Earlier that day, when I was talking to FSS, I remember him saying Z dew pt spread, but they are not calling for fog. He then warned me that they could be mistaken. Sps was clear and visibility sounded good. At that time sps approach wanted to vector me for the backcourse 15R. DH on 15R is 400'. This was not low enough, so I requested the ILS 33L, with a tailwind. Sps approach approved. I shot the ILS 33L, missed, got vectors and shut it again, and missed and diverted. Once on the ground I realized that I shot these 2 approachs one after the other west/O questioning the visibility. I returned to sps to talk to the WX station and found out that at the time first officer my approachs the visibility was 1/4 mi. The approach calls for 1/2 mi visibility. I was flying for a company under 135 regulations. By even starting to shoot the ILS 33L sps I was in violation because the visibility calls for 1/2 mi, not 1/4 mi.

Original NASA ASRS Text

Title: PART 135 ATX FRT SMT PLT INITIATES INS APCHS WITH WX BELOW MINIMUMS.

Narrative: I WAS ENRTE TO SPS FROM DAL. THE WX WAS CLR, BUT THERE WAS A 9 DEW PT SPREAD AT SPS. ARRIVING AT SPS I REMEMBER THE WIND WAS OUT OF THE S AT 7 KTS, CEILING 300' OBSCURED, FOG. I DO NOT REMEMBER HEARING THE VISIBILITY. EARLIER THAT DAY, WHEN I WAS TALKING TO FSS, I REMEMBER HIM SAYING Z DEW PT SPREAD, BUT THEY ARE NOT CALLING FOR FOG. HE THEN WARNED ME THAT THEY COULD BE MISTAKEN. SPS WAS CLR AND VISIBILITY SOUNDED GOOD. AT THAT TIME SPS APCH WANTED TO VECTOR ME FOR THE BACKCOURSE 15R. DH ON 15R IS 400'. THIS WAS NOT LOW ENOUGH, SO I REQUESTED THE ILS 33L, WITH A TAILWIND. SPS APCH APPROVED. I SHOT THE ILS 33L, MISSED, GOT VECTORS AND SHUT IT AGAIN, AND MISSED AND DIVERTED. ONCE ON THE GND I REALIZED THAT I SHOT THESE 2 APCHS ONE AFTER THE OTHER W/O QUESTIONING THE VISIBILITY. I RETURNED TO SPS TO TALK TO THE WX STATION AND FOUND OUT THAT AT THE TIME FO MY APCHS THE VISIBILITY WAS 1/4 MI. THE APCH CALLS FOR 1/2 MI VISIBILITY. I WAS FLYING FOR A COMPANY UNDER 135 REGS. BY EVEN STARTING TO SHOOT THE ILS 33L SPS I WAS IN VIOLATION BECAUSE THE VISIBILITY CALLS FOR 1/2 MI, NOT 1/4 MI.

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.