PC12 pilot and flight instructor experience autoplt malfunctions and subsequent altitude excursion.

Attributes
ACN	765452
Time
Date	200712
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : tpf.airport
State Reference	FL
Altitude	msl single value : 2200
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : tpa.tracon
Operator	general aviation : personal
Make Model Name	PC-12
Operating Under FAR Part	Part 91
Flight Plan	None
Aircraft 2
Flight Phase	climbout : takeoff
Route In Use	departure : on vectors
Person 1
Affiliation	other
Function	instruction : trainee
Qualification	pilot : private pilot : instrument
Experience	flight time last 90 days : 50 flight time total : 2500 flight time type : 12
ASRS Report	765452
Person 2
Affiliation	other
Function	instruction : instructor
Events
Anomaly	aircraft equipment problem : critical altitude deviation : overshoot conflict : airborne less severe non adherence : clearance other anomaly
Independent Detector	other flight crewa other flight crewb
Resolutory Action	flight crew : regained aircraft control
Consequence	faa : investigated
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

I and an instructor pilot departed tpf for a training flight. At 600 ft; we contacted tpa approach and were given a transponder code; heading; and cleared to 1600 ft. The autoplt was off; but the yoke went to a full deflection to the left. I overpowered it; hit the autoplt disconnect switch (even though the autoplt was not engaged). I got the plane on the correct heading and when approaching 1200 ft; we experienced a runaway trim and quickly climbed to 2200 ft. We then got the pitch under control and descended to 1600 ft. There was traffic north of us at about 2200 ft which we saw the entire time. He was northbound and we were nebound and we were never closer than approximately 1 mi. Tpa approach asked us to contact tpa; which we did upon landing back at tpf after training. Before we left tpf; while going through a preflight checklist; the autoplt malfunctioned; but seemed to work ok after that. We think that; upon taking off; the autoplt started another test procedure; which resulted in the above described maneuvers. In all other phases of this flight; the autoplt performed correctly and is working properly. It will undergo further tests to ensure that it is working correctly.

Original NASA ASRS Text

Title: PC12 PLT AND FLT INSTRUCTOR EXPERIENCE AUTOPLT MALFUNCTIONS AND SUBSEQUENT ALT EXCURSION.

Narrative: I AND AN INSTRUCTOR PLT DEPARTED TPF FOR A TRAINING FLT. AT 600 FT; WE CONTACTED TPA APCH AND WERE GIVEN A XPONDER CODE; HDG; AND CLRED TO 1600 FT. THE AUTOPLT WAS OFF; BUT THE YOKE WENT TO A FULL DEFLECTION TO THE L. I OVERPOWERED IT; HIT THE AUTOPLT DISCONNECT SWITCH (EVEN THOUGH THE AUTOPLT WAS NOT ENGAGED). I GOT THE PLANE ON THE CORRECT HDG AND WHEN APCHING 1200 FT; WE EXPERIENCED A RUNAWAY TRIM AND QUICKLY CLBED TO 2200 FT. WE THEN GOT THE PITCH UNDER CTL AND DSNDED TO 1600 FT. THERE WAS TFC N OF US AT ABOUT 2200 FT WHICH WE SAW THE ENTIRE TIME. HE WAS NBOUND AND WE WERE NEBOUND AND WE WERE NEVER CLOSER THAN APPROX 1 MI. TPA APCH ASKED US TO CONTACT TPA; WHICH WE DID UPON LNDG BACK AT TPF AFTER TRAINING. BEFORE WE LEFT TPF; WHILE GOING THROUGH A PREFLT CHKLIST; THE AUTOPLT MALFUNCTIONED; BUT SEEMED TO WORK OK AFTER THAT. WE THINK THAT; UPON TAKING OFF; THE AUTOPLT STARTED ANOTHER TEST PROC; WHICH RESULTED IN THE ABOVE DESCRIBED MANEUVERS. IN ALL OTHER PHASES OF THIS FLT; THE AUTOPLT PERFORMED CORRECTLY AND IS WORKING PROPERLY. IT WILL UNDERGO FURTHER TESTS TO ENSURE THAT IT IS WORKING CORRECTLY.

Data retrieved from NASA's ASRS site as of January 2009 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.