EMB140 flight crew has an altitude deviation during approach to pns.

Attributes
ACN	716519
Time
Date	200611
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : pns.airport
State Reference	FL
Altitude	msl single value : 1600
Environment
Flight Conditions	IMC
Light	Dusk
Aircraft 1
Controlling Facilities	tracon : p31.tracon tower : las.tower
Operator	common carrier : air carrier
Make Model Name	EMB ERJ 140 ER&LR
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	arrival star : vor 8
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	716579
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	non adherence : published procedure
Independent Detector	atc equipment : msaw other flight crewa other flight crewb
Resolutory Action	controller : issued advisory flight crew : returned to assigned altitude flight crew : overcame equipment problem
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Flight Crew Human Performance Aircraft
Primary Problem	Flight Crew Human Performance

Narrative:

On the VOR runway 8 approach into pns with scattered thunderstorms and occasional moderate turbulence we had a loss of 400 ft. This occurred after capturing in altitude mode 2000 ft; and then selecting 800 ft; which was the MDA for the approach. I was the PNF and told the first officer to climb back up to 2000 ft. Tower advised; 'low altitude alert;' at approximately the same time; this altitude deviation occurred just prior to the FAF. At the gate the first officer and I confirmed we captured altitude mode before selecting MDA. I believe later vertical speed mode was selected by accident due to the turbulent conditions.

Original NASA ASRS Text

Title: EMB140 FLT CREW HAS AN ALTDEV DURING APCH TO PNS.

Narrative: ON THE VOR RWY 8 APCH INTO PNS WITH SCATTERED TSTMS AND OCCASIONAL MODERATE TURB WE HAD A LOSS OF 400 FT. THIS OCCURRED AFTER CAPTURING IN ALT MODE 2000 FT; AND THEN SELECTING 800 FT; WHICH WAS THE MDA FOR THE APCH. I WAS THE PNF AND TOLD THE FO TO CLB BACK UP TO 2000 FT. TWR ADVISED; 'LOW ALT ALERT;' AT APPROX THE SAME TIME; THIS ALTDEV OCCURRED JUST PRIOR TO THE FAF. AT THE GATE THE FO AND I CONFIRMED WE CAPTURED ALT MODE BEFORE SELECTING MDA. I BELIEVE LATER VERT SPD MODE WAS SELECTED BY ACCIDENT DUE TO THE TURBULENT CONDITIONS.

Data retrieved from NASA's ASRS site as of January 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.