Small transport descends below minimum descent altitude in IFR approach.

Attributes
ACN	275275
Time
Date	199406
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : oma
State Reference	NE
Altitude	agl bound lower : 500 agl bound upper : 700
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : oma artcc : zbw
Operator	general aviation : instructional
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Route In Use	approach : straight in
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : cfi pilot : atp
Experience	flight time total : 9500
ASRS Report	275275
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	altitude deviation : overshoot inflight encounter : weather non adherence : published procedure non adherence : clearance other spatial deviation
Independent Detector	atc equipment other atc equipment : unspecified other controllera
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

On the approach to runway 32L (VOR) I broke out at 900 ft AGL, the MDA is 701 ft AGL. I had good ground contact and about 1 1/2 mi flight visibility. About 2 mi from the missed approach point, the tower issued a low altitude alert. I noted I was 150 ft below minimum descent altitude and immediately climbed back to minimum descent altitude. This put me in and out of the cloud bases. At 1/2 mi from missed approach point, I saw the runway environment and landed. What had happened was the broken layer had lowered from 900 ft to 700 ft. Being out of the clouds and over 500 ft AGL, I had made the error of flying visually instead of staying on the instruments as I should.

Original NASA ASRS Text

Title: SMT DSNDS BELOW MINIMUM DSCNT ALT IN IFR APCH.

Narrative: ON THE APCH TO RWY 32L (VOR) I BROKE OUT AT 900 FT AGL, THE MDA IS 701 FT AGL. I HAD GOOD GND CONTACT AND ABOUT 1 1/2 MI FLT VISIBILITY. ABOUT 2 MI FROM THE MISSED APCH POINT, THE TWR ISSUED A LOW ALT ALERT. I NOTED I WAS 150 FT BELOW MINIMUM DSCNT ALT AND IMMEDIATELY CLBED BACK TO MINIMUM DSCNT ALT. THIS PUT ME IN AND OUT OF THE CLOUD BASES. AT 1/2 MI FROM MISSED APCH POINT, I SAW THE RWY ENVIRONMENT AND LANDED. WHAT HAD HAPPENED WAS THE BROKEN LAYER HAD LOWERED FROM 900 FT TO 700 FT. BEING OUT OF THE CLOUDS AND OVER 500 FT AGL, I HAD MADE THE ERROR OF FLYING VISUALLY INSTEAD OF STAYING ON THE INSTS AS I SHOULD.

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.