Altitude deviation. Overshoot on descent.

Attributes
ACN	125379
Time
Date	198910
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : bsr
State Reference	CA
Altitude	msl bound lower : 15000 msl bound upper : 16000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zoa
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	arrival other arrival star : star
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 160 flight time total : 10500 flight time type : 1400
ASRS Report	125379
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	altitude deviation : crossing restriction not met non adherence : clearance non adherence : published procedure other anomaly
Independent Detector	other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

On descent to sfo cleared for big sur profile descent runway 28. Descent calls to cross anjee at or above 16,000' with next restriction to cross skunk below 12,000 or at or above 10,000. Aircraft was in VNAV path descent with restrictions in flight management computer (FMC). Altitude alert on mode control panel (MCP) was set for 10,000' restriction at skunk as FMC had restriction for anjee programmed. Went to vertical speed mode on MCP to reduce speed. While out of VNAV autoplt will not level off for anjee restriction without 16,000 set in altitude alert. Crossed anjee below 16,000'. No traffic conflict and no mention was made by ATC (or me, of course). I feel that excursion was caused by my putting 10,000 in altitude alert as opposed to 16,000 for anjee and recycling on FMC for restriction. Lesson learned: in future put current restriction in altitude alert on MCP regardless of what's programmed in FMC or what mode autoplt is in.

Original NASA ASRS Text

Title: ALT DEVIATION. OVERSHOOT ON DESCENT.

Narrative: ON DSCNT TO SFO CLRED FOR BIG SUR PROFILE DSCNT RWY 28. DSCNT CALLS TO CROSS ANJEE AT OR ABOVE 16,000' WITH NEXT RESTRICTION TO CROSS SKUNK BELOW 12,000 OR AT OR ABOVE 10,000. ACFT WAS IN VNAV PATH DSCNT WITH RESTRICTIONS IN FLT MGMNT COMPUTER (FMC). ALT ALERT ON MODE CTL PANEL (MCP) WAS SET FOR 10,000' RESTRICTION AT SKUNK AS FMC HAD RESTRICTION FOR ANJEE PROGRAMMED. WENT TO VERTICAL SPEED MODE ON MCP TO REDUCE SPEED. WHILE OUT OF VNAV AUTOPLT WILL NOT LEVEL OFF FOR ANJEE RESTRICTION WITHOUT 16,000 SET IN ALT ALERT. CROSSED ANJEE BELOW 16,000'. NO TFC CONFLICT AND NO MENTION WAS MADE BY ATC (OR ME, OF COURSE). I FEEL THAT EXCURSION WAS CAUSED BY MY PUTTING 10,000 IN ALT ALERT AS OPPOSED TO 16,000 FOR ANJEE AND RECYCLING ON FMC FOR RESTRICTION. LESSON LEARNED: IN FUTURE PUT CURRENT RESTRICTION IN ALT ALERT ON MCP REGARDLESS OF WHAT'S PROGRAMMED IN FMC OR WHAT MODE AUTOPLT IS IN.

Data retrieved from NASA's ASRS site as of August 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.