A CL65 in cruise at FL280 experienced an uncommanded pitch up towards FL290 caused by a failed air d...

Attributes
ACN	473478
Time
Date	200005
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : cvg.airport
State Reference	KY
Altitude	msl single value : 28000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zid.artcc
Operator	common carrier : air carrier
Make Model Name	Regional Jet CL65, Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	cruise : level
Route In Use	enroute airway : j80.airway
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : multi engine pilot : atp
Experience	flight time last 90 days : 210 flight time total : 6500 flight time type : 2000
ASRS Report	473478
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : critical altitude deviation : excursion from assigned altitude non adherence : published procedure other anomaly other
Independent Detector	other flight crewa other flight crewb
Consequence	other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

While in cruise at FL280, the aircraft pitched uncommanded towards FL290 as a result of an air data computer/mach trim failure. The autoplt was disengaged by myself (PF). Leveled near FL290 and then returned to FL280. QRH procedures were accomplished and ATC notified. They asked if we needed assistance. The aircraft was controllable in VMC conditions and no conflicts were present. The landing occurred without incident.

Original NASA ASRS Text

Title: A CL65 IN CRUISE AT FL280 EXPERIENCED AN UNCOMMANDED PITCH UP TOWARDS FL290 CAUSED BY A FAILED AIR DATA COMPUTER.

Narrative: WHILE IN CRUISE AT FL280, THE ACFT PITCHED UNCOMMANDED TOWARDS FL290 AS A RESULT OF AN AIR DATA COMPUTER/MACH TRIM FAILURE. THE AUTOPLT WAS DISENGAGED BY MYSELF (PF). LEVELED NEAR FL290 AND THEN RETURNED TO FL280. QRH PROCS WERE ACCOMPLISHED AND ATC NOTIFIED. THEY ASKED IF WE NEEDED ASSISTANCE. THE ACFT WAS CONTROLLABLE IN VMC CONDITIONS AND NO CONFLICTS WERE PRESENT. THE LNDG OCCURRED WITHOUT INCIDENT.

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.

A CL65 in cruise at FL280 experienced an uncommanded pitch up towards FL290 caused by a failed air data computer.