A B757-200 at FL310 deviated from assigned altitude.

Attributes
ACN	509868
Time
Date	200104
Day	Fri
Local Time Of Day	1201 To 1800
Place
State Reference	FL
Altitude	msl single value : 31000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zjx.artcc
Operator	common carrier : air carrier
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Flight Phase	climbout : vacating altitude
Route In Use	departure : on vectors
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 : 17500 flight time type : 317
ASRS Report	509868
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	other controllera other flight crewa
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

ZJX was controling our flight. At FL310 we asked for FL390. Lead flight attendant came into cockpit and was talking ot first officer concerning cabin temperature. First officer was PF. At this time ATC said, 'turn 20 degrees left for climb.' I acknowledged this. A few seconds later, flight attendant left cockpit and I told first officer that ATC wanted us to turn left 20 degrees for climb. First officer said ok and I left frequency to make PA. When I returned to ATC frequency, I realized we were in a climb. First officer said ATC asked why we left FL310. First officer misinterped my instruction 'to turn left 20 degrees for climb.' first officer thought we could climb to our requested altitude of FL390. Flight attendant came into cockpit at poor time (not her fault). I happened to give my PA at a bad time. Would not have left FL310 had I been in loop. It was a collection of items and bad timing.

Original NASA ASRS Text

Title: A B757-200 AT FL310 DEVIATED FROM ASSIGNED ALT.

Narrative: ZJX WAS CTLING OUR FLT. AT FL310 WE ASKED FOR FL390. LEAD FLT ATTENDANT CAME INTO COCKPIT AND WAS TALKING OT FO CONCERNING CABIN TEMP. FO WAS PF. AT THIS TIME ATC SAID, 'TURN 20 DEGS L FOR CLB.' I ACKNOWLEDGED THIS. A FEW SECONDS LATER, FLT ATTENDANT LEFT COCKPIT AND I TOLD FO THAT ATC WANTED US TO TURN L 20 DEGS FOR CLB. FO SAID OK AND I LEFT FREQ TO MAKE PA. WHEN I RETURNED TO ATC FREQ, I REALIZED WE WERE IN A CLB. FO SAID ATC ASKED WHY WE LEFT FL310. FO MISINTERPED MY INSTRUCTION 'TO TURN L 20 DEGS FOR CLB.' FO THOUGHT WE COULD CLB TO OUR REQUESTED ALT OF FL390. FLT ATTENDANT CAME INTO COCKPIT AT POOR TIME (NOT HER FAULT). I HAPPENED TO GIVE MY PA AT A BAD TIME. WOULD NOT HAVE LEFT FL310 HAD I BEEN IN LOOP. IT WAS A COLLECTION OF ITEMS AND BAD TIMING.

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.