Auththrottle problem results in altitude deviation for widebody transport.

Attributes
ACN	128675
Time
Date	198911
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : rzs
State Reference	CA
Altitude	msl bound lower : 34600 msl bound upper : 35000
Aircraft 1
Controlling Facilities	artcc : zau
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	cruise other
Route In Use	enroute : other oceanic enroute : pacific enroute airway : r576
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 22000
ASRS Report	128675
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : commercial
Experience	flight time last 90 days : 420 flight time total : 27000 flight time type : 1050
ASRS Report	128654
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	flight crew : overcame equipment problem flight crew : returned to intended course or assigned course flight crew : regained aircraft control
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

With thrust management engaged (light on), autothrottle system switch latched, no malfunction indications and .830 mach entered in the fmx, throttles slowly retarded. Crew caught airspeed decreasing through 250 KIAS, disconnected the autoplt, applied full power and descended approximately 400' to regain lost airspeed.

Original NASA ASRS Text

Title: AUTHTHROTTLE PROBLEM RESULTS IN ALT DEVIATION FOR WDB.

Narrative: WITH THRUST MGMNT ENGAGED (LIGHT ON), AUTOTHROTTLE SYS SWITCH LATCHED, NO MALFUNCTION INDICATIONS AND .830 MACH ENTERED IN THE FMX, THROTTLES SLOWLY RETARDED. CREW CAUGHT AIRSPD DECREASING THROUGH 250 KIAS, DISCONNECTED THE AUTOPLT, APPLIED FULL PWR AND DSNDED APPROX 400' TO REGAIN LOST AIRSPD.

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.