Narrative:

After departing lunken field we switched to departure and were given heading vectors, a 250 KT speed restriction and a climb to 12000'. The autoplt was coupled, and the mode control panel was programmed for altitude capture and heading track. We encountered moderate rain freezing and temperatures, so anti-ice was selected. Maintaining 250 KTS resulted in approximately 4000' per min rate of climb. We were given a chance to center frequency. At that moment the F/0 called '12000' and I saw that the aircraft was passing 12500 and climbing. The altitude select had not captured. I immediately disconnected the autoplt and pushed over to descended to 12000' MSL. I also instructed the first officer to report 'descending to 12000' to the departure controller. He did so. We leveled at the assigned altitude and were again instructed to contact center. Center gave us another altitude and we proceeded enroute. On the previous leg as well as the leg to follow, the altitude select captured and then disconnected on 2 level-offs involving descent. Neither involved deviation from assigned altitude. Both required manual level off. Discussion with this first officer indicated 2 other occasions on which he had similar experiences with this particular airplane. I personally recall another instance with this system near orl fl, in january, which could have been another failure of the same type. Aircraft company issued a service letter for 4 specific aircraft, which when complied with, resulted in wiring some FMS modes incorrectly to the autoflt system. This light transport aircraft is scheduled for rewiring on 3/th/88 at the factory service center. A test flight will follow involving automatic level-offs from high and low rates of climb and descent. I believe the automation of some of the elements of flying has taken the pilot out of the 'basic loop,' and the human challenge is to now manage the 'electronic assistants' efficiently and safely. One should always question the reliability of this equipment, even if you have no reason to suspect failure. Callback conversation revealed the following. The main reason this report was sent was the reporter's concern about the manufacturer's service letter that set up the problem. This corp owns three of the four aircraft that received the service letter and all have been modified and the problem apparently corrected. Reporter said he was concerned about this aircraft manufacturer's response to customer problems and thinks they seem more attune to small aircraft owner problems and tend to ignore the corporate sector.

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Original NASA ASRS Text

Title: CPR LTT ALT DEVIATION OVERSHOT DURING CLIMB.

Narrative: AFTER DEPARTING LUNKEN FIELD WE SWITCHED TO DEP AND WERE GIVEN HDG VECTORS, A 250 KT SPD RESTRICTION AND A CLB TO 12000'. THE AUTOPLT WAS COUPLED, AND THE MODE CONTROL PANEL WAS PROGRAMMED FOR ALT CAPTURE AND HDG TRACK. WE ENCOUNTERED MODERATE RAIN FREEZING AND TEMPS, SO ANTI-ICE WAS SELECTED. MAINTAINING 250 KTS RESULTED IN APPROX 4000' PER MIN RATE OF CLB. WE WERE GIVEN A CHANCE TO CTR FREQ. AT THAT MOMENT THE F/0 CALLED '12000' AND I SAW THAT THE ACFT WAS PASSING 12500 AND CLBING. THE ALT SELECT HAD NOT CAPTURED. I IMMEDIATELY DISCONNECTED THE AUTOPLT AND PUSHED OVER TO DESCENDED TO 12000' MSL. I ALSO INSTRUCTED THE F/O TO RPT 'DESCENDING TO 12000' TO THE DEP CTLR. HE DID SO. WE LEVELED AT THE ASSIGNED ALT AND WERE AGAIN INSTRUCTED TO CONTACT CTR. CTR GAVE US ANOTHER ALT AND WE PROCEEDED ENROUTE. ON THE PREVIOUS LEG AS WELL AS THE LEG TO FOLLOW, THE ALT SELECT CAPTURED AND THEN DISCONNECTED ON 2 LEVEL-OFFS INVOLVING DSCNT. NEITHER INVOLVED DEVIATION FROM ASSIGNED ALT. BOTH REQUIRED MANUAL LEVEL OFF. DISCUSSION WITH THIS F/O INDICATED 2 OTHER OCCASIONS ON WHICH HE HAD SIMILAR EXPERIENCES WITH THIS PARTICULAR AIRPLANE. I PERSONALLY RECALL ANOTHER INSTANCE WITH THIS SYS NEAR ORL FL, IN JANUARY, WHICH COULD HAVE BEEN ANOTHER FAILURE OF THE SAME TYPE. ACFT COMPANY ISSUED A SVC LETTER FOR 4 SPECIFIC ACFT, WHICH WHEN COMPLIED WITH, RESULTED IN WIRING SOME FMS MODES INCORRECTLY TO THE AUTOFLT SYS. THIS LTT ACFT IS SCHEDULED FOR REWIRING ON 3/TH/88 AT THE FACTORY SVC CENTER. A TEST FLT WILL FOLLOW INVOLVING AUTOMATIC LEVEL-OFFS FROM HIGH AND LOW RATES OF CLB AND DSCNT. I BELIEVE THE AUTOMATION OF SOME OF THE ELEMENTS OF FLYING HAS TAKEN THE PLT OUT OF THE 'BASIC LOOP,' AND THE HUMAN CHALLENGE IS TO NOW MANAGE THE 'ELECTRONIC ASSISTANTS' EFFICIENTLY AND SAFELY. ONE SHOULD ALWAYS QUESTION THE RELIABILITY OF THIS EQUIP, EVEN IF YOU HAVE NO REASON TO SUSPECT FAILURE. CALLBACK CONVERSATION REVEALED THE FOLLOWING. THE MAIN REASON THIS RPT WAS SENT WAS THE RPTR'S CONCERN ABOUT THE MANUFACTURER'S SERVICE LETTER THAT SET UP THE PROBLEM. THIS CORP OWNS THREE OF THE FOUR ACFT THAT RECEIVED THE SERVICE LETTER AND ALL HAVE BEEN MODIFIED AND THE PROBLEM APPARENTLY CORRECTED. RPTR SAID HE WAS CONCERNED ABOUT THIS ACFT MANUFACTURER'S RESPONSE TO CUSTOMER PROBLEMS AND THINKS THEY SEEM MORE ATTUNE TO SMALL ACFT OWNER PROBLEMS AND TEND TO IGNORE THE CORPORATE SECTOR.

Data retrieved from NASA's ASRS site as of August 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.