King air pilot has autoplt disengaged by passenger climbing out of the cockpit.

Attributes
ACN	714003
Time
Date	200610
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : zmp.artcc
State Reference	MN
Altitude	msl single value : 21000
Environment
Flight Conditions	VMC
Weather Elements	Turbulence
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zmp.artcc
Operator	general aviation : corporate
Make Model Name	King Air C90 E90
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : corporate
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : multi engine pilot : commercial
Experience	flight time last 90 days : 65 flight time total : 2250 flight time type : 350
ASRS Report	714003
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to assigned altitude
Supplementary
Problem Areas	Passenger Human Performance Aircraft Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

While flying in light to sometimes moderate turbulence (localized); a passenger that was sitting in right front seat (copilot's seat) was leaving seat to rejoin people in cabin. When he left the seat his pant leg caught the autoplt toggle on the pedestal and disconnected the autoplt. Altitude increased 200-300 ft in turbulence; and then I over-controled my correction resulting in a loss of about 800 ft; so getting to FL205 or so -- approximately 500 ft low! I immediately reestablished aircraft at correct altitude (FL210) and reengaged autoplt. There were no known conflicts; and ATC did not inquire as to the situation or to any altitude excursions. Of course; the entire situation would have been avoided had people not been moving about in the cockpit; and if I would have at least guarded the autoplt-flight director toggles with my hand; instead I was trying to help this person to get out of the seat. So; no more non-pilots in the cockpit; unless they agree to stay put for the entire flight; anyway.

Original NASA ASRS Text

Title: KING AIR PLT HAS AUTOPLT DISENGAGED BY PAX CLBING OUT OF THE COCKPIT.

Narrative: WHILE FLYING IN LIGHT TO SOMETIMES MODERATE TURB (LOCALIZED); A PAX THAT WAS SITTING IN R FRONT SEAT (COPLT'S SEAT) WAS LEAVING SEAT TO REJOIN PEOPLE IN CABIN. WHEN HE LEFT THE SEAT HIS PANT LEG CAUGHT THE AUTOPLT TOGGLE ON THE PEDESTAL AND DISCONNECTED THE AUTOPLT. ALT INCREASED 200-300 FT IN TURB; AND THEN I OVER-CTLED MY CORRECTION RESULTING IN A LOSS OF ABOUT 800 FT; SO GETTING TO FL205 OR SO -- APPROX 500 FT LOW! I IMMEDIATELY REESTABLISHED ACFT AT CORRECT ALT (FL210) AND REENGAGED AUTOPLT. THERE WERE NO KNOWN CONFLICTS; AND ATC DID NOT INQUIRE AS TO THE SITUATION OR TO ANY ALT EXCURSIONS. OF COURSE; THE ENTIRE SITUATION WOULD HAVE BEEN AVOIDED HAD PEOPLE NOT BEEN MOVING ABOUT IN THE COCKPIT; AND IF I WOULD HAVE AT LEAST GUARDED THE AUTOPLT-FLT DIRECTOR TOGGLES WITH MY HAND; INSTEAD I WAS TRYING TO HELP THIS PERSON TO GET OUT OF THE SEAT. SO; NO MORE NON-PLTS IN THE COCKPIT; UNLESS THEY AGREE TO STAY PUT FOR THE ENTIRE FLT; ANYWAY.

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.