Air taxi pilot descends below prescribed altitude on VOR approach.

Attributes
ACN	146524
Time
Date	199005
Day	Mon
Local Time Of Day	0001 To 0600
Place
Locale Reference	atc facility : lou
State Reference	KY
Altitude	msl bound lower : 1300 msl bound upper : 2500
Environment
Flight Conditions	Mixed
Light	Night
Aircraft 1
Controlling Facilities	tracon : sdf
Operator	common carrier : air taxi
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Retractable Gear
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	company : air taxi
Function	flight crew : single pilot
Qualification	pilot : commercial pilot : instrument pilot : atp
Experience	flight time last 90 days : 240 flight time total : 3100 flight time type : 300
ASRS Report	146524
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : published procedure
Independent Detector	other controllera
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

It was an early morning, I had been cruising at 5000' en route from nashville, tn, to louisville, ky, on V-515. When I was 10 mi from new hope VORTAC, I requested to intercept the 330 degree right of louisville VORTAC to prepare myself for the VOR runway 32 approach into bowman. Standiford approach, who was working my flight at the time, cleared me direct to the louisville VOR. I acknowledged and complied. Shortly thereafter I was cleared to intercept the 330 degree right and track inbound to the station. I complied, and was cleared down to 4000' soon afterwards. I was given a clearance to descend to 2500' at pilot's discretion. Soon after leveling, I was told to maintain 2500' until established on the final approach course and cleared VOR runway 32 approach into bowman. I acknowledged and had my radios already set up for the approach. The procedure says to maintain 2500' until crossing the VOR, then descend to 1300'. You then maintain 1300' until you are 3.4 DME from the station and then you may descend to your MDA of 1060'. This is the only approach at bowman field where the approach NAVAID is located in the middle of the procedure and not on the field. Instead of maintaining 2500' until crossing the VOR; I maintained 2500' until I was 10 mi from the VOR and then began my descent to 1300' planning to hold 1300' until 3.4 mi before the VOR. I was in error, I asked standiford approach if I could switch to bowman advisory. Their reply was 'you're still 20 mi from the airport, stay with me a little longer.' at this point I realized and corrected my altitude error. I am lucky that there were no obstructions in the area where I was. For some reason I memorized the correct numbers but performed the maneuvers associated with them on the wrong side of the NAVAID. Even though I did recall noticing this situation when I studied the approach plate, I forgot to account for it during the approach. When performing an instrument approach procedure, it pays to concentrate and think about what you are doing especially when the WX is IMC.

Original NASA ASRS Text

Title: AIR TAXI PLT DESCENDS BELOW PRESCRIBED ALT ON VOR APCH.

Narrative: IT WAS AN EARLY MORNING, I HAD BEEN CRUISING AT 5000' ENRTE FROM NASHVILLE, TN, TO LOUISVILLE, KY, ON V-515. WHEN I WAS 10 MI FROM NEW HOPE VORTAC, I REQUESTED TO INTERCEPT THE 330 DEG R OF LOUISVILLE VORTAC TO PREPARE MYSELF FOR THE VOR RWY 32 APCH INTO BOWMAN. STANDIFORD APCH, WHO WAS WORKING MY FLT AT THE TIME, CLRED ME DIRECT TO THE LOUISVILLE VOR. I ACKNOWLEDGED AND COMPLIED. SHORTLY THEREAFTER I WAS CLRED TO INTERCEPT THE 330 DEG R AND TRACK INBND TO THE STATION. I COMPLIED, AND WAS CLRED DOWN TO 4000' SOON AFTERWARDS. I WAS GIVEN A CLRNC TO DSND TO 2500' AT PLT'S DISCRETION. SOON AFTER LEVELING, I WAS TOLD TO MAINTAIN 2500' UNTIL ESTABLISHED ON THE FINAL APCH COURSE AND CLRED VOR RWY 32 APCH INTO BOWMAN. I ACKNOWLEDGED AND HAD MY RADIOS ALREADY SET UP FOR THE APCH. THE PROC SAYS TO MAINTAIN 2500' UNTIL XING THE VOR, THEN DSND TO 1300'. YOU THEN MAINTAIN 1300' UNTIL YOU ARE 3.4 DME FROM THE STATION AND THEN YOU MAY DSND TO YOUR MDA OF 1060'. THIS IS THE ONLY APCH AT BOWMAN FIELD WHERE THE APCH NAVAID IS LOCATED IN THE MIDDLE OF THE PROC AND NOT ON THE FIELD. INSTEAD OF MAINTAINING 2500' UNTIL XING THE VOR; I MAINTAINED 2500' UNTIL I WAS 10 MI FROM THE VOR AND THEN BEGAN MY DSNT TO 1300' PLANNING TO HOLD 1300' UNTIL 3.4 MI BEFORE THE VOR. I WAS IN ERROR, I ASKED STANDIFORD APCH IF I COULD SWITCH TO BOWMAN ADVISORY. THEIR REPLY WAS 'YOU'RE STILL 20 MI FROM THE ARPT, STAY WITH ME A LITTLE LONGER.' AT THIS POINT I REALIZED AND CORRECTED MY ALT ERROR. I AM LUCKY THAT THERE WERE NO OBSTRUCTIONS IN THE AREA WHERE I WAS. FOR SOME REASON I MEMORIZED THE CORRECT NUMBERS BUT PERFORMED THE MANEUVERS ASSOCIATED WITH THEM ON THE WRONG SIDE OF THE NAVAID. EVEN THOUGH I DID RECALL NOTICING THIS SITUATION WHEN I STUDIED THE APCH PLATE, I FORGOT TO ACCOUNT FOR IT DURING THE APCH. WHEN PERFORMING AN INSTRUMENT APCH PROC, IT PAYS TO CONCENTRATE AND THINK ABOUT WHAT YOU ARE DOING ESPECIALLY WHEN THE WX IS IMC.

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.