Stabilized approach concept compromised in visual approach clearance.

Attributes
ACN	293974
Time
Date	199501
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : dfw
State Reference	TX
Altitude	msl bound lower : 2850 msl bound upper : 3000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : dfw
Operator	common carrier : air carrier
Make Model Name	SF 340A
Operating Under FAR Part	Part 135
Navigation In Use	Other
Flight Phase	cruise other descent : approach
Route In Use	approach : visual approach : straight in
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 8200 flight time type : 2200
ASRS Report	293974
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : published procedure non adherence : clearance other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Pilot Deviation
Situations
ATC Facility	procedure or policy : unspecified

Narrative:

Level at 3000 ft on the localizer with runway in sight. The controller cleared us for the visual runway 31R, maintain 3000 ft until the marker, but the first officer started to follow the GS of the ILS. I realized what he was doing and intervened before we went too far under the assigned altitude (150 ft below). This could have been avoided if the controller had not given an unusual clearance. 3000 ft is the assigned GS interception altitude for this particular approach. We ended up above the GS with unstabilized approach criteria.

Original NASA ASRS Text

Title: STABILIZED APCH CONCEPT COMPROMISED IN VISUAL APCH CLRNC.

Narrative: LEVEL AT 3000 FT ON THE LOC WITH RWY IN SIGHT. THE CTLR CLRED US FOR THE VISUAL RWY 31R, MAINTAIN 3000 FT UNTIL THE MARKER, BUT THE FO STARTED TO FOLLOW THE GS OF THE ILS. I REALIZED WHAT HE WAS DOING AND INTERVENED BEFORE WE WENT TOO FAR UNDER THE ASSIGNED ALT (150 FT BELOW). THIS COULD HAVE BEEN AVOIDED IF THE CTLR HAD NOT GIVEN AN UNUSUAL CLRNC. 3000 FT IS THE ASSIGNED GS INTERCEPTION ALT FOR THIS PARTICULAR APCH. WE ENDED UP ABOVE THE GS WITH UNSTABILIZED APCH CRITERIA.

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.