B737-800 flight crew receives MSAW warning from smf tower while shooting a night visual approach.

Attributes
ACN	718824
Time
Date	200611
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : smf.airport
State Reference	CA
Altitude	agl single value : 1500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : smf.tower
Operator	common carrier : air carrier
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer & glide slope : 16l Other
Flight Phase	descent : approach
Route In Use	approach : visual approach : instrument precision
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : military pilot : flight engineer pilot : commercial pilot : atp pilot : instrument
Experience	flight time last 90 days : 210 flight time total : 11000 flight time type : 3500
ASRS Report	718824
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : private pilot : flight engineer pilot : instrument pilot : commercial pilot : atp pilot : multi engine
ASRS Report	719307
Events
Anomaly	other anomaly other spatial deviation
Independent Detector	atc equipment : msaw aircraft equipment : gpws
Resolutory Action	controller : issued alert flight crew : became reoriented flight crew : exited adverse environment
Supplementary
Problem Areas	Aircraft Airport Environmental Factor Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

While transitioning to a visual approach to runway 16L smf we received a check altitude alert from capital tower. Event occurred while starting approach from slightly above ILS GS (1900 ft MSL). While correcting to what to me appeared to be a visual 3.0 degree flight path we got the call from tower to check altitude (approximately 1500 ft AGL). PAPI's were extremely dim or not yet fully visible. Upon hearing the call from tower I returned my scan to inside and regained a proper GS. After the call from tower we also received glidepath alert from GPWS; which also brought my attention back inside to the ILS glidepath. Contributing factors: 1) fatigue: XA45 wakeup for an XC00 show. In addition it was the end of a 7:54 scheduled block day; duty day was scheduled for 10:14 hours. 2) perception: long and narrow runway in the middle of a vast field and valley. Visually I thought I was still above the 3.0 GS but in reality I wasn't.

Original NASA ASRS Text

Title: B737-800 FLT CREW RECEIVES MSAW WARNING FROM SMF TWR WHILE SHOOTING A NIGHT VISUAL APCH.

Narrative: WHILE TRANSITIONING TO A VISUAL APCH TO RWY 16L SMF WE RECEIVED A CHK ALT ALERT FROM CAPITAL TWR. EVENT OCCURRED WHILE STARTING APCH FROM SLIGHTLY ABOVE ILS GS (1900 FT MSL). WHILE CORRECTING TO WHAT TO ME APPEARED TO BE A VISUAL 3.0 DEG FLT PATH WE GOT THE CALL FROM TWR TO CHK ALT (APPROX 1500 FT AGL). PAPI'S WERE EXTREMELY DIM OR NOT YET FULLY VISIBLE. UPON HEARING THE CALL FROM TWR I RETURNED MY SCAN TO INSIDE AND REGAINED A PROPER GS. AFTER THE CALL FROM TWR WE ALSO RECEIVED GLIDEPATH ALERT FROM GPWS; WHICH ALSO BROUGHT MY ATTN BACK INSIDE TO THE ILS GLIDEPATH. CONTRIBUTING FACTORS: 1) FATIGUE: XA45 WAKEUP FOR AN XC00 SHOW. IN ADDITION IT WAS THE END OF A 7:54 SCHEDULED BLOCK DAY; DUTY DAY WAS SCHEDULED FOR 10:14 HRS. 2) PERCEPTION: LONG AND NARROW RWY IN THE MIDDLE OF A VAST FIELD AND VALLEY. VISUALLY I THOUGHT I WAS STILL ABOVE THE 3.0 GS BUT IN REALITY I WASN'T.

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.