Citation CE525A pilot has an altitude deviation in rvsm airspace.

Attributes
ACN	713686
Time
Date	200610
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : zjx.artcc
State Reference	FL
Altitude	msl single value : 40000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zjx.artcc
Operator	general aviation : personal
Make Model Name	Citationjet C525/C526
Operating Under FAR Part	Part 91
Flight Phase	cruise : enroute altitude change
Flight Plan	IFR
Person 1
Affiliation	other
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : multi engine pilot : commercial
Experience	flight time last 90 days : 50 flight time total : 2500 flight time type : 250
ASRS Report	713686
Person 2
Affiliation	government : faa
Function	controller : radar
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	other controllera
Resolutory Action	controller : issued advisory flight crew : returned to assigned altitude flight crew : overcame equipment problem
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Flight Crew Human Performance Aircraft
Primary Problem	Aircraft

Narrative:

Cruising at FL400 was given clearance to descend to FL350; autoplt abruptly climbed as noted by ZJX; manually disconnected autoplt and immediately descended to assigned altitude of FL350 and re-engaged autoplt. Queried ATC if there was any problem or any aircraft had to be diverted due to deviation and controller said no problem. ATC gave a 180 degree heading for descent. Checked autoplt system and was unable to duplicate occurrence and continued in rvsm airspace.

Original NASA ASRS Text

Title: CITATION CE525A PLT HAS AN ALTDEV IN RVSM AIRSPACE.

Narrative: CRUISING AT FL400 WAS GIVEN CLRNC TO DSND TO FL350; AUTOPLT ABRUPTLY CLBED AS NOTED BY ZJX; MANUALLY DISCONNECTED AUTOPLT AND IMMEDIATELY DSNDED TO ASSIGNED ALT OF FL350 AND RE-ENGAGED AUTOPLT. QUERIED ATC IF THERE WAS ANY PROB OR ANY ACFT HAD TO BE DIVERTED DUE TO DEV AND CTLR SAID NO PROB. ATC GAVE A 180 DEG HDG FOR DSCNT. CHKED AUTOPLT SYS AND WAS UNABLE TO DUPLICATE OCCURRENCE AND CONTINUED IN RVSM AIRSPACE.

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.