CL65 altitude deviation near sln of 2000 ft.

Attributes
ACN	454730
Time
Date	199911
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : sln.airport
State Reference	KS
Altitude	msl bound lower : 20000 msl bound upper : 22000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zkc.artcc
Operator	Other
Make Model Name	Challenger CL604
Operating Under FAR Part	Part 91
Navigation In Use	other other
Flight Phase	descent : intermediate altitude descent : vacating altitude
Route In Use	enroute other
Flight Plan	IFR
Person 1
Affiliation	company other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 60 flight time total : 6200 flight time type : 100
ASRS Report	454730
Person 2
Affiliation	company other
Function	flight crew : first officer
Qualification	pilot : commercial pilot : multi engine pilot : instrument
Events
Anomaly	aircraft equipment problem : critical altitude deviation : overshoot altitude deviation : excursion from assigned altitude non adherence : clearance non adherence : far other anomaly other
Independent Detector	aircraft equipment : altitude alert aircraft equipment other aircraft equipment : altitude capture ok autopilot other flight crewa
Resolutory Action	flight crew : returned to assigned altitude none taken : insufficient time
Consequence	other
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Ambiguous

Narrative:

During an experimental test flight, the autoplt failed to capture the selected altitude. Captain disconnected the autoplt and recaptured the assigned altitude manually. Postflt investigation found that a new software load had been compiled incorrectly and altitude capture was rendered inoperative. Since the descent was a steep angle at vmo, the altitude overshoot was approximately 2000 ft.

Original NASA ASRS Text

Title: CL65 ALTDEV NEAR SLN OF 2000 FT.

Narrative: DURING AN EXPERIMENTAL TEST FLT, THE AUTOPLT FAILED TO CAPTURE THE SELECTED ALT. CAPT DISCONNECTED THE AUTOPLT AND RECAPTURED THE ASSIGNED ALT MANUALLY. POSTFLT INVESTIGATION FOUND THAT A NEW SOFTWARE LOAD HAD BEEN COMPILED INCORRECTLY AND ALT CAPTURE WAS RENDERED INOP. SINCE THE DSCNT WAS A STEEP ANGLE AT VMO, THE ALT OVERSHOOT WAS APPROX 2000 FT.

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.