Pilot reports receiving low altitude warning from ATC during RNAV runway 15 kump approach.

Attributes
ACN	783267
Time
Date	200804
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : ump.airport
State Reference	IN
Altitude	agl single value : 500
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Small Aircraft Low Wing 1 Eng Retractable Gear
Operating Under FAR Part	Part 91
Navigation In Use	other
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : multi engine pilot : commercial
Experience	flight time last 90 days : 35 flight time total : 13000 flight time type : 1600
ASRS Report	783267
Events
Anomaly	aircraft equipment problem : critical non adherence : published procedure other spatial deviation
Independent Detector	atc equipment : msaw
Resolutory Action	controller : issued alert flight crew : took precautionary avoidance action
Consequence	other
Supplementary
Problem Areas	Flight Crew Human Performance Aircraft
Primary Problem	Ambiguous

Narrative:

AWOS reporting WX at ump airport 600 ft; 4 mi. While on GPS runway 15 approach; I let down to 500 ft AGL after the porco fix. My GPS VNAV is not working. Aircraft set up for waas approach; but later found a wiring error for the VNAV part. After letting down to 500 ft AGL after porco; the controller came on and said he had an altitude alert. After receiving that alert; I immediately pulled up. Seconds later; I got a visual on the airport; canceled IFR; and landed without further event.

Original NASA ASRS Text

Title: PILOT REPORTS RECEIVING LOW ALTITUDE WARNING FROM ATC DURING RNAV RWY 15 KUMP APPROACH.

Narrative: AWOS RPTING WX AT UMP ARPT 600 FT; 4 MI. WHILE ON GPS RWY 15 APCH; I LET DOWN TO 500 FT AGL AFTER THE PORCO FIX. MY GPS VNAV IS NOT WORKING. ACFT SET UP FOR WAAS APCH; BUT LATER FOUND A WIRING ERROR FOR THE VNAV PART. AFTER LETTING DOWN TO 500 FT AGL AFTER PORCO; THE CTLR CAME ON AND SAID HE HAD AN ALT ALERT. AFTER RECEIVING THAT ALERT; I IMMEDIATELY PULLED UP. SECONDS LATER; I GOT A VISUAL ON THE ARPT; CANCELED IFR; AND LANDED WITHOUT FURTHER EVENT.

Data retrieved from NASA's ASRS site as of May 2009 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.