A cessna 560XL in climb at 8000 ft had stabilizer miscompare light on, ran checklist and climbed to ...

Attributes
ACN	563341
Time
Date	200210
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : apa.airport
State Reference	CO
Altitude	msl single value : 8000
Environment
Flight Conditions	VMC
Weather Elements	Turbulence
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdv.artcc tracon : d01.tracon
Operator	general aviation : personal
Make Model Name	Citation V
Operating Under FAR Part	Part 91
Navigation In Use	other
Flight Phase	climbout : initial cruise : enroute altitude change
Route In Use	departure : on vectors
Flight Plan	IFR
Person 1
Affiliation	other
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : commercial pilot : cfi pilot : atp pilot : multi engine
Experience	flight time last 90 days : 150 flight time total : 6000 flight time type : 500
ASRS Report	563341
Person 2
Affiliation	other
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : miscompare light other flight crewa other flight crewb
Resolutory Action	aircraft : automation overrode flight crew flight crew : overcame equipment problem flight crew : landed as precaution flight crew : diverted to another airport
Consequence	other
Supplementary
Problem Areas	Chart Or Publication Aircraft Flight Crew Human Performance
Primary Problem	Aircraft

Narrative:

After takeoff and flaps up, hydraulic pressure light was noted out. Approximately 15 seconds after light noted out, stabilizer miscompare light illuminated. Aircraft was slowed in climb and checklists were completed, to include R2 for miscompare light. Limitations were 200 KTS/mach .62 on airspeed and FL410. We called maintenance and decided to divert to ZZZ to a service center. After deviation coordination and completion of normal checklists, we climbed to FL310. Checklist H2 was run for the accompanying hydraulic pressure light on. When pulling the hydraulic control circuit breaker, a loud thump was felt and heard, once pushing in the circuit breaker, same thump was felt and heard. Approximately 10 seconds later, the stabilizer moved down, causing pitch deviations and stabilizer miscompare light extinguished. Due to the shudder felt while the malfunction was in progress, and uncertainty of the stabilizer continuing to work and effect on pitch control, the decision was made to divert to apa. (Stabilizer miscompare light was on for approximately 30 mins.) callback conversation with reporter revealed the following information: the reporter stated the miscompare light is a function of the comparison of stabilizer position and flap position. The reporter said in this case, the flaps were fully retracted and the miscompare light was on continuously until the circuit breaker was pulled (with a loud thump) and reset (again with a loud thump), accompanied with the stabilizer moving down. The reporter stated with the stabilizer moving, the miscompare light went out, but the pitch deviations started and the decision was then made to divert. The reporter said the maintenance action is unknown but the airplane is now flying.

Original NASA ASRS Text

Title: A CESSNA 560XL IN CLB AT 8000 FT HAD STABILIZER MISCOMPARE LIGHT ON, RAN CHKLIST AND CLBED TO FL310. DIVERTED DUE TO PITCH DEVS. CAUSE UNKNOWN.

Narrative: AFTER TKOF AND FLAPS UP, HYD PRESSURE LIGHT WAS NOTED OUT. APPROX 15 SECONDS AFTER LIGHT NOTED OUT, STABILIZER MISCOMPARE LIGHT ILLUMINATED. ACFT WAS SLOWED IN CLB AND CHKLISTS WERE COMPLETED, TO INCLUDE R2 FOR MISCOMPARE LIGHT. LIMITATIONS WERE 200 KTS/MACH .62 ON AIRSPD AND FL410. WE CALLED MAINT AND DECIDED TO DIVERT TO ZZZ TO A SVC CTR. AFTER DEV COORD AND COMPLETION OF NORMAL CHKLISTS, WE CLBED TO FL310. CHKLIST H2 WAS RUN FOR THE ACCOMPANYING HYD PRESSURE LIGHT ON. WHEN PULLING THE HYD CTL CIRCUIT BREAKER, A LOUD THUMP WAS FELT AND HEARD, ONCE PUSHING IN THE CIRCUIT BREAKER, SAME THUMP WAS FELT AND HEARD. APPROX 10 SECONDS LATER, THE STABILIZER MOVED DOWN, CAUSING PITCH DEVS AND STABILIZER MISCOMPARE LIGHT EXTINGUISHED. DUE TO THE SHUDDER FELT WHILE THE MALFUNCTION WAS IN PROGRESS, AND UNCERTAINTY OF THE STABILIZER CONTINUING TO WORK AND EFFECT ON PITCH CTL, THE DECISION WAS MADE TO DIVERT TO APA. (STABILIZER MISCOMPARE LIGHT WAS ON FOR APPROX 30 MINS.) CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE MISCOMPARE LIGHT IS A FUNCTION OF THE COMPARISON OF STABILIZER POS AND FLAP POS. THE RPTR SAID IN THIS CASE, THE FLAPS WERE FULLY RETRACTED AND THE MISCOMPARE LIGHT WAS ON CONTINUOUSLY UNTIL THE CIRCUIT BREAKER WAS PULLED (WITH A LOUD THUMP) AND RESET (AGAIN WITH A LOUD THUMP), ACCOMPANIED WITH THE STABILIZER MOVING DOWN. THE RPTR STATED WITH THE STABILIZER MOVING, THE MISCOMPARE LIGHT WENT OUT, BUT THE PITCH DEVS STARTED AND THE DECISION WAS THEN MADE TO DIVERT. THE RPTR SAID THE MAINT ACTION IS UNKNOWN BUT THE AIRPLANE IS NOW FLYING.

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 cessna 560XL in climb at 8000 ft had stabilizer miscompare light on, ran checklist and climbed to FL310. Diverted due to pitch deviations. Cause unknown.