CL65 crew had the stabilizer control channels both fail rendering the stabilizer trim system inopera...

Attributes
ACN	462745
Time
Date	200002
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : ord.airport
State Reference	IL
Altitude	msl bound lower : 400 msl bound upper : 3000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : c90.tracon
Operator	common carrier : air carrier
Make Model Name	Regional Jet CL65, Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	climbout : initial
Route In Use	departure : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : cfi pilot : atp
Experience	flight time last 90 days : 200 flight time total : 6000 flight time type : 1000
ASRS Report	462745
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : atp
Experience	flight time last 90 days : 160 flight time total : 3500 flight time type : 1100
ASRS Report	462998
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	other flight crewa other flight crewb
Resolutory Action	flight crew : diverted to another airport
Consequence	other
Factors
Maintenance	contributing factor : schedule pressure performance deficiency : testing performance deficiency : inspection performance deficiency : fault isolation
Supplementary
Problem Areas	Aircraft Maintenance Human Performance
Primary Problem	Aircraft

Narrative:

After departing runway 4L at ord (chicago O'hare airport) and passing through approximately 400 ft AGL. Both stabilizer trim channels and mach trim disengaged. I advised ord departure that we needed to return to the airport, and maintain 3000 ft (5000 ft was the departure clearance altitude). The first officer (PF) was unable to trim the aircraft at 3000 ft and was using physical force as well power changes to maintain altitude. However an altitude of 3500 ft was reached before descending back to 3000 ft. We were eventually able to re-engage the trim system and landed (it failed on touchdown). In the future we will ask for a block altitude or discretion in a similar situation. We did not declare an emergency because the trim system re-engaged and operated until landing. Callback conversation with reporter revealed the following information: air carrier maintenance was unable to find any problem. They signed the discrepancy off as 'unable to duplicate, ground checked ok.' they attempted to have the crew depart with the same aircraft. The captain refused. The air carrier chief pilot then attempted to coerce the captain into reconsidering. He still refused. The CL65 has two computer channels that control the stabilizer. Trim switch input goes through the computers. There is no direct control that does not go through the computers. Both of them tripped off, rendering the stabilizer trim system inoperative. There is supposed to be an EICAS fault message displayed when a computer trip occurs. None was displayed.

Original NASA ASRS Text

Title: CL65 CREW HAD THE STABILIZER CTL CHANNELS BOTH FAIL RENDERING THE STABILIZER TRIM SYS INOP.

Narrative: AFTER DEPARTING RWY 4L AT ORD (CHICAGO O'HARE ARPT) AND PASSING THROUGH APPROX 400 FT AGL. BOTH STABILIZER TRIM CHANNELS AND MACH TRIM DISENGAGED. I ADVISED ORD DEP THAT WE NEEDED TO RETURN TO THE ARPT, AND MAINTAIN 3000 FT (5000 FT WAS THE DEP CLRNC ALT). THE FO (PF) WAS UNABLE TO TRIM THE ACFT AT 3000 FT AND WAS USING PHYSICAL FORCE AS WELL PWR CHANGES TO MAINTAIN ALT. HOWEVER AN ALT OF 3500 FT WAS REACHED BEFORE DESCENDING BACK TO 3000 FT. WE WERE EVENTUALLY ABLE TO RE-ENGAGE THE TRIM SYS AND LANDED (IT FAILED ON TOUCHDOWN). IN THE FUTURE WE WILL ASK FOR A BLOCK ALT OR DISCRETION IN A SIMILAR SIT. WE DID NOT DECLARE AN EMER BECAUSE THE TRIM SYS RE-ENGAGED AND OPERATED UNTIL LANDING. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: ACR MAINT WAS UNABLE TO FIND ANY PROB. THEY SIGNED THE DISCREPANCY OFF AS 'UNABLE TO DUPLICATE, GND CHECKED OK.' THEY ATTEMPTED TO HAVE THE CREW DEPART WITH THE SAME ACFT. THE CAPT REFUSED. THE ACR CHIEF PLT THEN ATTEMPTED TO COERCE THE CAPT INTO RECONSIDERING. HE STILL REFUSED. THE CL65 HAS TWO COMPUTER CHANNELS THAT CTL THE STABILIZER. TRIM SWITCH INPUT GOES THROUGH THE COMPUTERS. THERE IS NO DIRECT CTL THAT DOES NOT GO THROUGH THE COMPUTERS. BOTH OF THEM TRIPPED OFF, RENDERING THE STABILIZER TRIM SYS INOP. THERE IS SUPPOSED TO BE AN EICAS FAULT MESSAGE DISPLAYED WHEN A COMPUTER TRIP OCCURS. NONE WAS DISPLAYED.

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.

CL65 crew had the stabilizer control channels both fail rendering the stabilizer trim system inoperative.