Altitude excursion during maintenance test of autoplt.

Attributes
ACN	442262
Time
Date	199906
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : pdz.vor
State Reference	CA
Altitude	msl bound lower : 9000 msl bound upper : 10000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : sct.tracon
Operator	general aviation : corporate
Make Model Name	Turbo Commander 690C
Operating Under FAR Part	Part 91
Navigation In Use	other vortac
Flight Phase	cruise : level
Route In Use	enroute airway : v16.airway
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : sct.tracon
Operator	general aviation : corporate
Make Model Name	Cessna Citation Undifferentiated or Other Model
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Route In Use	enroute airway : v16.airway
Flight Plan	IFR
Person 1
Affiliation	company : corporate
Function	flight crew : single pilot
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 100 flight time total : 5000 flight time type : 100
ASRS Report	442262
Person 2
Affiliation	other
Function	maintenance : technician
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude conflict : airborne critical maintenance problem : improper maintenance non adherence : clearance
Independent Detector	atc equipment other atc equipment : radar aircraft equipment : altitude alert other controllera other flight crewa
Resolutory Action	controller : issued new clearance flight crew : overrode automation flight crew : returned to original clearance flight crew : took precautionary avoidance action
Consequence	faa : reviewed incident with flight crew other
Miss Distance	horizontal : 3000 vertical : 200
Factors
Maintenance	performance deficiency : testing performance deficiency : repair
Supplementary
Problem Areas	Flight Crew Human Performance Maintenance Human Performance Aircraft
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

The purpose of the flight was a maintenance 'test hop' to verify some squawks and evaluate some corrective actions. 2 of the system being evaluated were the autoplt and pressurization. 1 mechanic was in the right front seat working system, another was in the back taking notes. The pressurization test required a climb to FL200. I received a 'pop-up' IFR clearance from cno ground control. I departed cno and turned toward pdz VOR. The clearance included a turn to join V16 eastbound toward trm VOR. Socal TRACON issued several intermediate leveloffs, including one to maintain 9000 ft MSL for opposing traffic on V16 (the citation). I had been using the autoplt for most of the flight -- testing the various modes. I engaged 'altitude hold' at 9000 ft and diverted my attention to helping the mechanic with another system. The altitude alerter chime brought my attention back to the altimeter. The autoplt had trimmed the airplane full nose up, and we were at 9500 ft MSL and climbing rapidly. I initiated an immediate descending right turn just as the controller gave evasive instructions to both me and the citation. Controller advised loss of IFR separation down to 200 ft and 1/2 mi. Future maintenance flts of this type should be limited to VFR only, or a second pilot to assist the mechanics should be aboard.

Original NASA ASRS Text

Title: ALT EXCURSION DURING MAINT TEST OF AUTOPLT.

Narrative: THE PURPOSE OF THE FLT WAS A MAINT 'TEST HOP' TO VERIFY SOME SQUAWKS AND EVALUATE SOME CORRECTIVE ACTIONS. 2 OF THE SYS BEING EVALUATED WERE THE AUTOPLT AND PRESSURIZATION. 1 MECH WAS IN THE R FRONT SEAT WORKING SYS, ANOTHER WAS IN THE BACK TAKING NOTES. THE PRESSURIZATION TEST REQUIRED A CLB TO FL200. I RECEIVED A 'POP-UP' IFR CLRNC FROM CNO GND CTL. I DEPARTED CNO AND TURNED TOWARD PDZ VOR. THE CLRNC INCLUDED A TURN TO JOIN V16 EBOUND TOWARD TRM VOR. SOCAL TRACON ISSUED SEVERAL INTERMEDIATE LEVELOFFS, INCLUDING ONE TO MAINTAIN 9000 FT MSL FOR OPPOSING TFC ON V16 (THE CITATION). I HAD BEEN USING THE AUTOPLT FOR MOST OF THE FLT -- TESTING THE VARIOUS MODES. I ENGAGED 'ALT HOLD' AT 9000 FT AND DIVERTED MY ATTN TO HELPING THE MECH WITH ANOTHER SYS. THE ALT ALERTER CHIME BROUGHT MY ATTN BACK TO THE ALTIMETER. THE AUTOPLT HAD TRIMMED THE AIRPLANE FULL NOSE UP, AND WE WERE AT 9500 FT MSL AND CLBING RAPIDLY. I INITIATED AN IMMEDIATE DSNDING R TURN JUST AS THE CTLR GAVE EVASIVE INSTRUCTIONS TO BOTH ME AND THE CITATION. CTLR ADVISED LOSS OF IFR SEPARATION DOWN TO 200 FT AND 1/2 MI. FUTURE MAINT FLTS OF THIS TYPE SHOULD BE LIMITED TO VFR ONLY, OR A SECOND PLT TO ASSIST THE MECHS SHOULD BE ABOARD.

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.