B777 flight crew has altitude deviation while on arrival to rjaa.

Attributes
ACN	694588
Time
Date	200604
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : rjaa.airport
State Reference	FO
Altitude	msl single value : 13000
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : rjaa.tracon
Operator	common carrier : air carrier
Make Model Name	B777 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
ASRS Report	694588
Person 2
Affiliation	company : air carrier
Function	flight crew : relief pilot
ASRS Report	694381
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : overshoot non adherence : published procedure non adherence : clearance
Independent Detector	aircraft equipment other aircraft equipment : alt alerter other flight crewa other flight crewb
Resolutory Action	flight crew : returned to original clearance
Supplementary
Problem Areas	Flight Crew Human Performance Aircraft
Primary Problem	Aircraft

Narrative:

Descending into rjaa we were cleared to 13000 ft. 13000 ft was set in the altitude window and indicated on the pfd. At 14500 ft the altimeter was reset to 29.41. The autoplt failed to capture 13000 ft and the PF disconnected the autoplt at 12700 ft and manually returned the aircraft to 13000 ft. The autoplt was reconnected but it wanted to start a descent again. PNF entered 13000 ft in the FMC on the VNAV; cruise page and the autoplt was then re-engaged. It then maintained 13000 ft. No more problems were noted and tokyo approach control had no response to the altitude deviation. I seem to remember a bulletin warning of the fact that the autoplt may not level the aircraft off at an altitude close to the transition altitude if there is an excessive change from high to low on the barometer. I think it was taken out after a change to software.

Original NASA ASRS Text

Title: B777 FLT CREW HAS ALTDEV WHILE ON ARR TO RJAA.

Narrative: DSNDING INTO RJAA WE WERE CLRED TO 13000 FT. 13000 FT WAS SET IN THE ALT WINDOW AND INDICATED ON THE PFD. AT 14500 FT THE ALTIMETER WAS RESET TO 29.41. THE AUTOPLT FAILED TO CAPTURE 13000 FT AND THE PF DISCONNECTED THE AUTOPLT AT 12700 FT AND MANUALLY RETURNED THE ACFT TO 13000 FT. THE AUTOPLT WAS RECONNECTED BUT IT WANTED TO START A DSCNT AGAIN. PNF ENTERED 13000 FT IN THE FMC ON THE VNAV; CRUISE PAGE AND THE AUTOPLT WAS THEN RE-ENGAGED. IT THEN MAINTAINED 13000 FT. NO MORE PROBS WERE NOTED AND TOKYO APCH CTL HAD NO RESPONSE TO THE ALTDEV. I SEEM TO REMEMBER A BULLETIN WARNING OF THE FACT THAT THE AUTOPLT MAY NOT LEVEL THE ACFT OFF AT AN ALT CLOSE TO THE TRANSITION ALT IF THERE IS AN EXCESSIVE CHANGE FROM HIGH TO LOW ON THE BAROMETER. I THINK IT WAS TAKEN OUT AFTER A CHANGE TO SOFTWARE.

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.