Flight crew of an light transport inadvertently climbed above assigned altitude.

Attributes
ACN	291989
Time
Date	199412
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : txk
State Reference	AR
Altitude	msl bound lower : 16000 msl bound upper : 16600
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Brasilia EMB-120 All Series
Operating Under FAR Part	Part 135
Navigation In Use	Other Other
Flight Phase	cruise other
Route In Use	enroute airway : zfw
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 200 flight time total : 12000
ASRS Report	291989
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	controller : issued new clearance flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

In cruise flight at 16000 ft, first officer was flying. ZFW called with a pilot's discretion descent to 11000 ft and a new altimeter setting considerably higher than what was set. When I changed either the selected altitude or the altimeter, I do not know which one caused the problem -- the altitude hold mode on the autoplt disengaged. I went back to filling out the logbook and neither I nor the first officer, who was flying, noticed the aircraft begin to climb. When the altitude alerter sounded, we both disengaged the autoplt and nosed over, but the aircraft had already gone through 16600 ft, no doubt alerting the center controller who, although he did not request our altitude or mention it in any way, ordered an immediate descent to 16000 ft. This is a classic case of trust in aircraft system to the extent of not following through with a change of setting with observing that the system was performing properly before looking away from it. There was no excuse for me to not ensure that the altimeter and altitude settings did not affect -- as they sometimes do -- the autoplt and there was also no reason for us to not notice the aircraft beginning to climb.

Original NASA ASRS Text

Title: FLC OF AN LTT INADVERTENTLY CLBED ABOVE ASSIGNED ALT.

Narrative: IN CRUISE FLT AT 16000 FT, FO WAS FLYING. ZFW CALLED WITH A PLT'S DISCRETION DSCNT TO 11000 FT AND A NEW ALTIMETER SETTING CONSIDERABLY HIGHER THAN WHAT WAS SET. WHEN I CHANGED EITHER THE SELECTED ALT OR THE ALTIMETER, I DO NOT KNOW WHICH ONE CAUSED THE PROB -- THE ALT HOLD MODE ON THE AUTOPLT DISENGAGED. I WENT BACK TO FILLING OUT THE LOGBOOK AND NEITHER I NOR THE FO, WHO WAS FLYING, NOTICED THE ACFT BEGIN TO CLB. WHEN THE ALT ALERTER SOUNDED, WE BOTH DISENGAGED THE AUTOPLT AND NOSED OVER, BUT THE ACFT HAD ALREADY GONE THROUGH 16600 FT, NO DOUBT ALERTING THE CTR CTLR WHO, ALTHOUGH HE DID NOT REQUEST OUR ALT OR MENTION IT IN ANY WAY, ORDERED AN IMMEDIATE DSCNT TO 16000 FT. THIS IS A CLASSIC CASE OF TRUST IN ACFT SYS TO THE EXTENT OF NOT FOLLOWING THROUGH WITH A CHANGE OF SETTING WITH OBSERVING THAT THE SYS WAS PERFORMING PROPERLY BEFORE LOOKING AWAY FROM IT. THERE WAS NO EXCUSE FOR ME TO NOT ENSURE THAT THE ALTIMETER AND ALT SETTINGS DID NOT AFFECT -- AS THEY SOMETIMES DO -- THE AUTOPLT AND THERE WAS ALSO NO REASON FOR US TO NOT NOTICE THE ACFT BEGINNING TO CLB.

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.