First officer on B737 on visual approach to gum receives low altitude alert warning from local contr...

Attributes
ACN	630538
Time
Date	200409
Day	Tue
Local Time Of Day	0001 To 0600
Place
Locale Reference	airport : gum.airport
State Reference	GU
Altitude	msl single value : 1500
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tower : gum.tower
Operator	common carrier : air carrier
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer & glide slope : 6l
Flight Phase	descent : approach
Route In Use	approach : instrument precision
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
ASRS Report	630538
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	other anomaly other anomaly other
Independent Detector	aircraft equipment : altitude alert other controllera
Resolutory Action	none taken : anomaly accepted
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Flight Crew Human Performance Environmental Factor
Primary Problem	Flight Crew Human Performance

Narrative:

Cleared to land after having received approach clearance with guam center for ILS runway 6L agana. Aircraft operated on/above GS at all times during approach. Prior to 1000 ft call, tower advised that a low terrain warning received. Aircraft was slightly above GS while hand flown by first officer. This situation would have required a mandatory go around in IMC. PAPI's and GS both confirmed on GS. Safety concern is that false warning will create atmosphere in which pilots may disregard warnings in IMC when a threat actually exists.

Original NASA ASRS Text

Title: FO ON B737 ON VISUAL APCH TO GUM RECEIVES LOW ALT ALERT WARNING FROM LCL CTLR.

Narrative: CLRED TO LAND AFTER HAVING RECEIVED APCH CLRNC WITH GUAM CTR FOR ILS RWY 6L AGANA. ACFT OPERATED ON/ABOVE GS AT ALL TIMES DURING APCH. PRIOR TO 1000 FT CALL, TWR ADVISED THAT A LOW TERRAIN WARNING RECEIVED. ACFT WAS SLIGHTLY ABOVE GS WHILE HAND FLOWN BY FO. THIS SIT WOULD HAVE REQUIRED A MANDATORY GAR IN IMC. PAPI'S AND GS BOTH CONFIRMED ON GS. SAFETY CONCERN IS THAT FALSE WARNING WILL CREATE ATMOSPHERE IN WHICH PLTS MAY DISREGARD WARNINGS IN IMC WHEN A THREAT ACTUALLY EXISTS.

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.

First officer on B737 on visual approach to gum receives low altitude alert warning from local controller.