Air taxi cargo aircraft has jumpseat passenger knock off the autoplt creating an altitude deviation.

Attributes
ACN	294930
Time
Date	199501
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : cds
State Reference	TX
Altitude	msl bound lower : 33000 msl bound upper : 33300
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zfw artcc : ztl
Operator	common carrier : air taxi
Make Model Name	Falcon 20FJF/20C/20D/20E/20F
Operating Under FAR Part	Part 135
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	company : air taxi
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 13000 flight time type : 325
ASRS Report	294930
Person 2
Affiliation	company : air taxi
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	other controllera
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Air Traffic Incident	Pilot Deviation

Narrative:

While level at FL330 autoplt was engaged, aircraft jumpseat was occupied by a company rider who inadvertently kicked center console and disengaged autoplt. Aircraft gained about 300 ft before being returned to FL330. ATC asked of our altitude and stated they showed us 300-400 ft high. In future it would be of value to brief jumpseat riders of position of autoplt and possible problems caused when they interfere with aircraft system. I don't believe our altitude deviation interfered with any other aircraft. However this could have caused problems. Other factors which added to our problem is the fact that our aircraft rarely carry jumpseat passenger so problem like this I haven't seen before.

Original NASA ASRS Text

Title: AIR TAXI CARGO ACFT HAS JUMPSEAT PAX KNOCK OFF THE AUTOPLT CREATING AN ALTDEV.

Narrative: WHILE LEVEL AT FL330 AUTOPLT WAS ENGAGED, ACFT JUMPSEAT WAS OCCUPIED BY A COMPANY RIDER WHO INADVERTENTLY KICKED CTR CONSOLE AND DISENGAGED AUTOPLT. ACFT GAINED ABOUT 300 FT BEFORE BEING RETURNED TO FL330. ATC ASKED OF OUR ALT AND STATED THEY SHOWED US 300-400 FT HIGH. IN FUTURE IT WOULD BE OF VALUE TO BRIEF JUMPSEAT RIDERS OF POS OF AUTOPLT AND POSSIBLE PROBS CAUSED WHEN THEY INTERFERE WITH ACFT SYS. I DON'T BELIEVE OUR ALTDEV INTERFERED WITH ANY OTHER ACFT. HOWEVER THIS COULD HAVE CAUSED PROBS. OTHER FACTORS WHICH ADDED TO OUR PROB IS THE FACT THAT OUR ACFT RARELY CARRY JUMPSEAT PAX SO PROB LIKE THIS I HAVEN'T SEEN BEFORE.

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