Cpr jet flight crew descends below cleared altitude on approach in vps airspace.

Attributes
ACN	420202
Time
Date	199811
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : dts
State Reference	FL
Altitude	msl bound lower : 700 msl bound upper : 1500
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Operator	general aviation : corporate
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : first officer
Experience	flight time last 90 days : 40 flight time total : 7900 flight time type : 300
ASRS Report	420202
Person 2
Affiliation	Other
Function	flight crew : captain oversight : pic
Events
Anomaly	altitude deviation : excursion from assigned altitude other anomaly other other spatial deviation
Independent Detector	other controllera
Consequence	Other
Supplementary
Air Traffic Incident	Pilot Deviation

Narrative:

On ASR approach to runway 14 at dts, eglin approach final controller was giving us vectors. His transmitter was very 'scratchy' and hard to understand. The captain and I heard an altitude of '500 ft' and no preliminary before that due to poor transmission. We started our descent to 500 ft out of 1500 ft. About 700 ft MSL the controller issued an altitude alert, at which time we climbed back to original altitude of 1500 ft. We acknowledge that we thought he said descent to 500 ft when in fact he said 'MDA of 500 ft' which we could not understand due to intermittent transmitter.

Original NASA ASRS Text

Title: CPR JET FLC DSNDS BELOW CLRED ALT ON APCH IN VPS AIRSPACE.

Narrative: ON ASR APCH TO RWY 14 AT DTS, EGLIN APCH FINAL CTLR WAS GIVING US VECTORS. HIS XMITTER WAS VERY 'SCRATCHY' AND HARD TO UNDERSTAND. THE CAPT AND I HEARD AN ALT OF '500 FT' AND NO PRELIMINARY BEFORE THAT DUE TO POOR XMISSION. WE STARTED OUR DSCNT TO 500 FT OUT OF 1500 FT. ABOUT 700 FT MSL THE CTLR ISSUED AN ALT ALERT, AT WHICH TIME WE CLBED BACK TO ORIGINAL ALT OF 1500 FT. WE ACKNOWLEDGE THAT WE THOUGHT HE SAID DSCNT TO 500 FT WHEN IN FACT HE SAID 'MDA OF 500 FT' WHICH WE COULD NOT UNDERSTAND DUE TO INTERMITTENT XMITTER.

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.