A B757-200 at FL410 noted airspeed retarded with no autothrottle correction.

Attributes
ACN	494362
Time
Date	200012
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : abq.airport
State Reference	NM
Altitude	msl single value : 41000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zab.artcc
Operator	common carrier : air carrier
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 20000 flight time type : 1000
ASRS Report	494362
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : multi engine
Events
Anomaly	aircraft equipment problem : less severe other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : airspeed indicator other flight crewa other flight crewb
Resolutory Action	controller : issued new clearance none taken : anomaly accepted
Consequence	other
Supplementary
Problem Areas	Weather Flight Crew Human Performance Aircraft
Primary Problem	Flight Crew Human Performance

Narrative:

After 1 hour at FL410, our airspeed retarded without our autothrottles correcting for this loss of indicated airspeed. Once we noticed the low airspeed, we disconnected the autothrottles and manually set the maximum continuous airspeed setting. The aircraft accelerated very slowly so we asked for a lower altitude. We received clearance to FL370 from center and by descending we're able to pick up our airspeed faster. Flight at FL370 was normal. At dfw (our destination) we wrote up the autothrottle malfunction for maintenance to troubleshoot.

Original NASA ASRS Text

Title: A B757-200 AT FL410 NOTED AIRSPD RETARDED WITH NO AUTOTHROTTLE CORRECTION.

Narrative: AFTER 1 HR AT FL410, OUR AIRSPD RETARDED WITHOUT OUR AUTOTHROTTLES CORRECTING FOR THIS LOSS OF INDICATED AIRSPD. ONCE WE NOTICED THE LOW AIRSPD, WE DISCONNECTED THE AUTOTHROTTLES AND MANUALLY SET THE MAX CONTINUOUS AIRSPD SETTING. THE ACFT ACCELERATED VERY SLOWLY SO WE ASKED FOR A LOWER ALT. WE RECEIVED CLRNC TO FL370 FROM CTR AND BY DSNDING WE'RE ABLE TO PICK UP OUR AIRSPD FASTER. FLT AT FL370 WAS NORMAL. AT DFW (OUR DEST) WE WROTE UP THE AUTOTHROTTLE MALFUNCTION FOR MAINT TO TROUBLESHOOT.

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.