Altitude excursion west of mfd VORTAC.

Attributes
ACN	491020
Time
Date	200011
Day	Sat
Local Time Of Day	1201 To 1800
Place
State Reference	OH
Altitude	msl bound lower : 36750 msl bound upper : 37000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : corporate
Make Model Name	Falcon 10C
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : corporate
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 150 flight time total : 9000 flight time type : 200
ASRS Report	491020
Person 2
Affiliation	company : corporate
Function	flight crew : first officer
Qualification	pilot : atp pilot : multi engine pilot : cfi
Experience	flight time last 90 days : 150 flight time total : 1520 flight time type : 150
ASRS Report	491019
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	other controllerb
Resolutory Action	controller : issued advisory flight crew : returned to assigned altitude
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

While in cruise confign on autoplt at FL370, the autoplt disconnected and the aircraft descended 250 ft to 36,750 feet MSL. The center controller advised that we were 400 ft low, at which time we corrected the altitude back to FL370. We were never more than 250 ft off altitude. To prevent future occurrences, we will have autoplt checked for proper operation.

Original NASA ASRS Text

Title: ALT EXCURSION W OF MFD VORTAC.

Narrative: WHILE IN CRUISE CONFIGN ON AUTOPLT AT FL370, THE AUTOPLT DISCONNECTED AND THE ACFT DSNDED 250 FT TO 36,750 FEET MSL. THE CTR CTLR ADVISED THAT WE WERE 400 FT LOW, AT WHICH TIME WE CORRECTED THE ALT BACK TO FL370. WE WERE NEVER MORE THAN 250 FT OFF ALT. TO PREVENT FUTURE OCCURRENCES, WE WILL HAVE AUTOPLT CHKED FOR PROPER OP.

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.