M-21 descends below ATC assigned altitude while making a VOR DME-B approach to mdq.

Attributes
ACN	602429
Time
Date	200312
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : rqz.vortac
State Reference	AL
Altitude	msl single value : 1930
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : hsv.tracon
Operator	general aviation : personal
Make Model Name	M-20 G Statesman
Operating Under FAR Part	Part 91
Navigation In Use	other vortac
Flight Phase	descent : approach
Route In Use	approach : instrument non precision arrival : on vectors
Flight Plan	IFR
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : private pilot : instrument
Experience	flight time last 90 days : 32 flight time total : 380 flight time type : 300
ASRS Report	602429
Person 2
Affiliation	government : faa
Function	controller : approach
Events
Anomaly	altitude deviation : crossing restriction not met altitude deviation : excursion from assigned altitude non adherence : published procedure non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	controller : issued advisory flight crew : became reoriented flight crew : returned to assigned altitude
Supplementary
Problem Areas	Chart Or Publication Flight Crew Human Performance Airport
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I departed hsv on runway 36R heading. I was told to join rqz 250 degree radial for mdq VOR/DME-B approach and maintain 2900 ft until established, cleared for VOR/DME-B approach. I selected the approach with my GNS-430, verified rqz turned on the 250 degree radial. I verified the plate, then descended to 1930 ft before crossing rqz. I looked to verify hutun and noticed I had not crossed rqz. ATC called and requested my altitude while I was climbing back to 2900 ft. I crossed rqz and finished the approach with no further errors. Contributing factors are the short distance of the total flight and the steep descent angle of the approach. This is a demanding non-precision approach that I will fly more often for the experience.

Original NASA ASRS Text

Title: M-21 DSNDS BELOW ATC ASSIGNED ALT WHILE MAKING A VOR DME-B APCH TO MDQ.

Narrative: I DEPARTED HSV ON RWY 36R HEADING. I WAS TOLD TO JOIN RQZ 250 DEG RADIAL FOR MDQ VOR/DME-B APCH AND MAINTAIN 2900 FT UNTIL ESTABLISHED, CLRED FOR VOR/DME-B APCH. I SELECTED THE APCH WITH MY GNS-430, VERIFIED RQZ TURNED ON THE 250 DEG RADIAL. I VERIFIED THE PLATE, THEN DSNDED TO 1930 FT BEFORE XING RQZ. I LOOKED TO VERIFY HUTUN AND NOTICED I HAD NOT CROSSED RQZ. ATC CALLED AND REQUESTED MY ALT WHILE I WAS CLBING BACK TO 2900 FT. I CROSSED RQZ AND FINISHED THE APCH WITH NO FURTHER ERRORS. CONTRIBUTING FACTORS ARE THE SHORT DISTANCE OF THE TOTAL FLT AND THE STEEP DSCNT ANGLE OF THE APCH. THIS IS A DEMANDING NON-PRECISION APCH THAT I WILL FLY MORE OFTEN FOR THE EXPERIENCE.

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.