<< >> NASA ASRS Report 227049, November 1992

Pilots of small aircraft private aircraft inadvertently descended below the GS during an ILS approach resulting in ATC issuing 'low altitude alert.'

Attributes
ACN	227049
Time
Date	199211
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : ict
State Reference	KS
Altitude	msl bound lower : 800 msl bound upper : 800
Environment
Flight Conditions	IMC
Light	Dusk
Aircraft 1
Controlling Facilities	tracon : ict
Operator	general aviation : personal
Make Model Name	Small Aircraft, High Wing, 1 Eng, Retractable Gear
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	Other
Function	instruction : instructor
Qualification	pilot : atp pilot : flight engineer pilot : cfi
Experience	flight time last 90 days : 8 flight time total : 4200 flight time type : 8
ASRS Report	227049
Person 2
Affiliation	Other
Function	instruction : trainee
Qualification	pilot : private
Events
Anomaly	non adherence : far non adherence : clearance 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	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Vectored from victor 12 to intercept localizer. While descending from 5000 ft, intercepted apparent GS. Tracked GS while intercepting localizer. Descended to 800 ft AGL when realized we never passed the OM and DME was approximately 13 mi. Tower advised us of a low altitude alert. We climbed to intercept real GS at about 2900 ft MSL and continued approach to successful landing. Chain of events: slow getting airplane from 5000 ft to 3000 ft. Failure to identify OM and crossing altitude. Poor positional awareness (distance to airport, marker, etc). Contributing factor: GS needle covers GS flag when indicating aircraft slightly below GS. This prevent right seat pilot from seeing flag. Also red panel lights 'wash out' the flag making it difficult to see at night. Human performance considerations: fatigue. Early morning departure after less than 4 hours sleep. Approach conducted after 8 hours flying.

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Original NASA ASRS Text

Title: PLTS OF SMA PVT ACFT INADVERTENTLY DSNDED BELOW THE GS DURING AN ILS APCH RESULTING IN ATC ISSUING 'LOW ALT ALERT.'

Narrative: VECTORED FROM VICTOR 12 TO INTERCEPT LOC. WHILE DSNDING FROM 5000 FT, INTERCEPTED APPARENT GS. TRACKED GS WHILE INTERCEPTING LOC. DSNDED TO 800 FT AGL WHEN REALIZED WE NEVER PASSED THE OM AND DME WAS APPROX 13 MI. TWR ADVISED US OF A LOW ALT ALERT. WE CLBED TO INTERCEPT REAL GS AT ABOUT 2900 FT MSL AND CONTINUED APCH TO SUCCESSFUL LNDG. CHAIN OF EVENTS: SLOW GETTING AIRPLANE FROM 5000 FT TO 3000 FT. FAILURE TO IDENT OM AND XING ALT. POOR POSITIONAL AWARENESS (DISTANCE TO ARPT, MARKER, ETC). CONTRIBUTING FACTOR: GS NEEDLE COVERS GS FLAG WHEN INDICATING ACFT SLIGHTLY BELOW GS. THIS PREVENT R SEAT PLT FROM SEEING FLAG. ALSO RED PANEL LIGHTS 'WASH OUT' THE FLAG MAKING IT DIFFICULT TO SEE AT NIGHT. HUMAN PERFORMANCE CONSIDERATIONS: FATIGUE. EARLY MORNING DEP AFTER LESS THAN 4 HRS SLEEP. APCH CONDUCTED AFTER 8 HRS FLYING.

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.