Narrative:

In cruise flight at FL410; on autoplt; approximately 100 NM west of hbu; a passenger came forward to advise that the cabin phone was ringing incessantly. I was the PIC and PF; so I took the radio. The sic; PNF; dealt with the passenger and the phone issue. ATC issued a frequency change. I acknowledged and looked down to enter the new frequency into the honeywell. When I looked up; the aircraft was rolling toward 45 degrees of bank and the altitude was decreasing. I smoothly recovered my bank and pitch to return the aircraft to proper course and altitude. I advised ATC on the new frequency that I was returning to FL410. ATC evidenced no awareness of any deviation -- either altitude or course. I re-engaged the autoplt; we ran the autoplt malfunction checklist; discovered the aircraft was trimmed to favor a roll to the right. I retrimmed the aircraft and continued to our destination without further incident. The autoplt shut down with warning or annunciation either audio or visual. As I was recovering; I did notice that both the autoplt and yaw damper function lights were out; but the audio and visual annunciators failed to sound. At the time of the event; we were about 5 KTS below mmo yet we didn't reach or exceed the red line. We did receive an audio bank warning as the recovery was initiated. After reaching our destination; we got the passenger on their way and advised the company through the on-duty assistant chief pilot. Contributing factors: sic distraction by passenger and cabin equipment problem. PIC flying and distraction from the pfd by entering frequency change just when the autoplt shut off without annunciation.

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Original NASA ASRS Text

Title: UNCOMMANDED AUTOPLT DISCONNECT AT FL410 RESULTS IN ROLL AND ALT LOSS.

Narrative: IN CRUISE FLT AT FL410; ON AUTOPLT; APPROX 100 NM W OF HBU; A PAX CAME FORWARD TO ADVISE THAT THE CABIN PHONE WAS RINGING INCESSANTLY. I WAS THE PIC AND PF; SO I TOOK THE RADIO. THE SIC; PNF; DEALT WITH THE PAX AND THE PHONE ISSUE. ATC ISSUED A FREQ CHANGE. I ACKNOWLEDGED AND LOOKED DOWN TO ENTER THE NEW FREQ INTO THE HONEYWELL. WHEN I LOOKED UP; THE ACFT WAS ROLLING TOWARD 45 DEGS OF BANK AND THE ALT WAS DECREASING. I SMOOTHLY RECOVERED MY BANK AND PITCH TO RETURN THE ACFT TO PROPER COURSE AND ALT. I ADVISED ATC ON THE NEW FREQ THAT I WAS RETURNING TO FL410. ATC EVIDENCED NO AWARENESS OF ANY DEV -- EITHER ALT OR COURSE. I RE-ENGAGED THE AUTOPLT; WE RAN THE AUTOPLT MALFUNCTION CHKLIST; DISCOVERED THE ACFT WAS TRIMMED TO FAVOR A ROLL TO THE R. I RETRIMMED THE ACFT AND CONTINUED TO OUR DEST WITHOUT FURTHER INCIDENT. THE AUTOPLT SHUT DOWN WITH WARNING OR ANNUNCIATION EITHER AUDIO OR VISUAL. AS I WAS RECOVERING; I DID NOTICE THAT BOTH THE AUTOPLT AND YAW DAMPER FUNCTION LIGHTS WERE OUT; BUT THE AUDIO AND VISUAL ANNUNCIATORS FAILED TO SOUND. AT THE TIME OF THE EVENT; WE WERE ABOUT 5 KTS BELOW MMO YET WE DIDN'T REACH OR EXCEED THE RED LINE. WE DID RECEIVE AN AUDIO BANK WARNING AS THE RECOVERY WAS INITIATED. AFTER REACHING OUR DEST; WE GOT THE PAX ON THEIR WAY AND ADVISED THE COMPANY THROUGH THE ON-DUTY ASSISTANT CHIEF PLT. CONTRIBUTING FACTORS: SIC DISTR BY PAX AND CABIN EQUIP PROB. PIC FLYING AND DISTR FROM THE PFD BY ENTERING FREQ CHANGE JUST WHEN THE AUTOPLT SHUT OFF WITHOUT ANNUNCIATION.

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.