Pilot descended below instrument approach altitude due to a GS indicator failure during an ILS appro...

Attributes
ACN	281760
Time
Date	199408
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : btr
State Reference	LA
Altitude	msl bound lower : 800 msl bound upper : 1600
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : btr tower : alb
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : private
Experience	flight time last 90 days : 29 flight time total : 1785 flight time type : 29
ASRS Report	281760
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : less severe other anomaly other other spatial deviation
Independent Detector	atc equipment other atc equipment : unspecified other controllera
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation other

Narrative:

On mon/aug/94, at approximately XA15 hours, while returning from denton, tx, on an IFR trip to baton rouge, la, I experienced a GS equipment failure which caused me to have an altitude deviation. I had checked the ILS morse code identifier prior to being cleared for the approach. Baton rouge approach gave me an assigned altitude of 1600 ft, then cleared me for the ILS runway 13 approach. While navigating by localizer, my GS indicator came alive and the GS flag went away. My GS indicator came down until centered, at which time I started my descent. I realized that my GS was malfunctioning simultaneously with the tower alerting me of my low altitude (800 ft), and I made an immediate ascent to a safe altitude. I continued into the airport in VMC conditions without incident.

Original NASA ASRS Text

Title: PLT DSNDED BELOW INST APCH ALT DUE TO A GS INDICATOR FAILURE DURING AN ILS APCH.

Narrative: ON MON/AUG/94, AT APPROX XA15 HRS, WHILE RETURNING FROM DENTON, TX, ON AN IFR TRIP TO BATON ROUGE, LA, I EXPERIENCED A GS EQUIP FAILURE WHICH CAUSED ME TO HAVE AN ALT DEV. I HAD CHKED THE ILS MORSE CODE IDENTIFIER PRIOR TO BEING CLRED FOR THE APCH. BATON ROUGE APCH GAVE ME AN ASSIGNED ALT OF 1600 FT, THEN CLRED ME FOR THE ILS RWY 13 APCH. WHILE NAVIGATING BY LOC, MY GS INDICATOR CAME ALIVE AND THE GS FLAG WENT AWAY. MY GS INDICATOR CAME DOWN UNTIL CTRED, AT WHICH TIME I STARTED MY DSCNT. I REALIZED THAT MY GS WAS MALFUNCTIONING SIMULTANEOUSLY WITH THE TWR ALERTING ME OF MY LOW ALT (800 FT), AND I MADE AN IMMEDIATE ASCENT TO A SAFE ALT. I CONTINUED INTO THE ARPT IN VMC CONDITIONS WITHOUT INCIDENT.

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.

Pilot descended below instrument approach altitude due to a GS indicator failure during an ILS approach.