Narrative:

While on an IFR flight; I was the captain of a king air 300 that experienced a landing gear failure during a visual approach to runway. 7 mi from touchdown; the gear was selected to the down position and nothing happened. We immediately advised tower of the situation and we were cleared to 3000 ft on a heading of 240 degrees. The plane was being hand flown at the time. Upon hearing the new clearance; I thought I had reached down to engage the autoplt while my copilot and I attempted to resolve our gear problem. After several tries; it was clear the gear was not going to lower normally. During our evaluation of the problem; approach asked if we were having trouble holding our altitude and that we were climbing. I immediately discovered the autoplt never engaged and the aircraft was slowly drifting in an ascent. I remember seeing 3400 ft when I forcibly pushed the controls over and regained the assigned 3000 ft. We were then given a clearance to 4000 ft on a heading of 270 degrees where I requested a direct route to divert to ZZZ1 to prepare for the manual extension process; landing; and subsequent repairs. The altitude excursion lasted less than 45 seconds from the time I thought I had engaged the autoplt and receiving a call from ATC on the altitude deviation; however; it was still an excursion. In my judgement; declaring an emergency was not necessary. We train annually. Although training does help; it never completely readies you for the actual event in your own aircraft. There is that sense of concern -- will my system work as advertised having never had to lower the gear manually in 21 yrs of flying the same aircraft?

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Original NASA ASRS Text

Title: BE30 CAPTAIN HAS ALT DEV WHILE DIAGNOSING LNDG GEAR PROBLEM.

Narrative: WHILE ON AN IFR FLT; I WAS THE CAPT OF A KING AIR 300 THAT EXPERIENCED A LNDG GEAR FAILURE DURING A VISUAL APCH TO RWY. 7 MI FROM TOUCHDOWN; THE GEAR WAS SELECTED TO THE DOWN POS AND NOTHING HAPPENED. WE IMMEDIATELY ADVISED TWR OF THE SITUATION AND WE WERE CLRED TO 3000 FT ON A HDG OF 240 DEGS. THE PLANE WAS BEING HAND FLOWN AT THE TIME. UPON HEARING THE NEW CLRNC; I THOUGHT I HAD REACHED DOWN TO ENGAGE THE AUTOPLT WHILE MY COPLT AND I ATTEMPTED TO RESOLVE OUR GEAR PROB. AFTER SEVERAL TRIES; IT WAS CLR THE GEAR WAS NOT GOING TO LOWER NORMALLY. DURING OUR EVALUATION OF THE PROB; APCH ASKED IF WE WERE HAVING TROUBLE HOLDING OUR ALT AND THAT WE WERE CLBING. I IMMEDIATELY DISCOVERED THE AUTOPLT NEVER ENGAGED AND THE ACFT WAS SLOWLY DRIFTING IN AN ASCENT. I REMEMBER SEEING 3400 FT WHEN I FORCIBLY PUSHED THE CTLS OVER AND REGAINED THE ASSIGNED 3000 FT. WE WERE THEN GIVEN A CLRNC TO 4000 FT ON A HDG OF 270 DEGS WHERE I REQUESTED A DIRECT RTE TO DIVERT TO ZZZ1 TO PREPARE FOR THE MANUAL EXTENSION PROCESS; LNDG; AND SUBSEQUENT REPAIRS. THE ALT EXCURSION LASTED LESS THAN 45 SECONDS FROM THE TIME I THOUGHT I HAD ENGAGED THE AUTOPLT AND RECEIVING A CALL FROM ATC ON THE ALTDEV; HOWEVER; IT WAS STILL AN EXCURSION. IN MY JUDGEMENT; DECLARING AN EMER WAS NOT NECESSARY. WE TRAIN ANNUALLY. ALTHOUGH TRAINING DOES HELP; IT NEVER COMPLETELY READIES YOU FOR THE ACTUAL EVENT IN YOUR OWN ACFT. THERE IS THAT SENSE OF CONCERN -- WILL MY SYS WORK AS ADVERTISED HAVING NEVER HAD TO LOWER THE GEAR MANUALLY IN 21 YRS OF FLYING THE SAME ACFT?

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