Both pilots input information to the autoplt and one cancelled the other resulting in climbing above...

Attributes
ACN	358110
Time
Date	199701
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : vuz
State Reference	AL
Altitude	msl bound lower : 16000 msl bound upper : 16500
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : ztl
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 240 flight time total : 8250 flight time type : 4750
ASRS Report	358110
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	altitude deviation : overshoot non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to assigned altitude
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

In cruise flight at 16000 ft we were given a revised altimeter setting which caused a significant change in indicated altitude. We were also given a descent clearance in the form of a crossing restr. The PF commanded his flight director to 'climb' in an effort to correct the indicated altitude change caused by the new altimeter setting. The autoplt followed this command, however, the PNF had set the altitude given in the descent clearance in the altitude pre-selector. This action removed the altitude reference for the autoplt 'climb' function. Concurrent to these events, both pilots became distraction discussing a plan to deviate around precipitation being depicted by radar. Due to the improper autoplt input the airplane deviated vertically (climbed above) from the assigned altitude. Upon noticing the deviation we disconnected the autoplt and manually flew the airplane back to the correct altitude. After the situation was correct we queried the controller, reporting our deviation and asking if this had caused any problem. He replied it did not. Better cockpit communications and division of tasks, with regard to the radar distraction, would have prevented this event.

Original NASA ASRS Text

Title: BOTH PLTS INPUT INFO TO THE AUTOPLT AND ONE CANCELLED THE OTHER RESULTING IN CLBING ABOVE ASSIGNED ALT.

Narrative: IN CRUISE FLT AT 16000 FT WE WERE GIVEN A REVISED ALTIMETER SETTING WHICH CAUSED A SIGNIFICANT CHANGE IN INDICATED ALT. WE WERE ALSO GIVEN A DSCNT CLRNC IN THE FORM OF A XING RESTR. THE PF COMMANDED HIS FLT DIRECTOR TO 'CLB' IN AN EFFORT TO CORRECT THE INDICATED ALT CHANGE CAUSED BY THE NEW ALTIMETER SETTING. THE AUTOPLT FOLLOWED THIS COMMAND, HOWEVER, THE PNF HAD SET THE ALT GIVEN IN THE DSCNT CLRNC IN THE ALT PRE-SELECTOR. THIS ACTION REMOVED THE ALT REF FOR THE AUTOPLT 'CLB' FUNCTION. CONCURRENT TO THESE EVENTS, BOTH PLTS BECAME DISTR DISCUSSING A PLAN TO DEVIATE AROUND PRECIP BEING DEPICTED BY RADAR. DUE TO THE IMPROPER AUTOPLT INPUT THE AIRPLANE DEVIATED VERTLY (CLBED ABOVE) FROM THE ASSIGNED ALT. UPON NOTICING THE DEV WE DISCONNECTED THE AUTOPLT AND MANUALLY FLEW THE AIRPLANE BACK TO THE CORRECT ALT. AFTER THE SIT WAS CORRECT WE QUERIED THE CTLR, RPTING OUR DEV AND ASKING IF THIS HAD CAUSED ANY PROB. HE REPLIED IT DID NOT. BETTER COCKPIT COMS AND DIVISION OF TASKS, WITH REGARD TO THE RADAR DISTR, WOULD HAVE PREVENTED THIS EVENT.

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.

Both pilots input information to the autoplt and one cancelled the other resulting in climbing above assigned altitude.