Light transport crew had a flight attendant enter cockpit when under sterile cockpit rules.

Attributes
ACN	433060
Time
Date	199904
Day	Sun
Local Time Of Day	0601 To 1200
Place
State Reference	TX
Altitude	msl single value : 9500
Aircraft 1
Controlling Facilities	artcc : zfw.artcc artcc : edff.artcc
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	other vortac
Flight Phase	descent : vacating altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 100 flight time total : 6000 flight time type : 2200
ASRS Report	433060
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : commercial pilot : instrument
Events
Anomaly	non adherence : published procedure non adherence : far non adherence : company policies
Independent Detector	other flight crewb
Resolutory Action	other
Supplementary
Problem Areas	Flight Crew Human Performance

Narrative:

Sterile cockpit violation. Flight attendant (who had been told she was welcome 'up front' in cruise) entered cockpit during a shallow descent through about 9000-9500 ft MSL. I immediately conveyed that we were in sterile cockpit and she apologetically exited immediately. The main cause was the simultaneous activation of the seat belt and sterile cockpit signs, coupled with a shallow (unnoticeable?) descent. Flight attendant didn't realize sterile cockpit was in effect. No conflict or abnormal sits occurred due to this.

Original NASA ASRS Text

Title: LTT CREW HAD A FLT ATTENDANT ENTER COCKPIT WHEN UNDER STERILE COCKPIT RULES.

Narrative: STERILE COCKPIT VIOLATION. FLT ATTENDANT (WHO HAD BEEN TOLD SHE WAS WELCOME 'UP FRONT' IN CRUISE) ENTERED COCKPIT DURING A SHALLOW DSCNT THROUGH ABOUT 9000-9500 FT MSL. I IMMEDIATELY CONVEYED THAT WE WERE IN STERILE COCKPIT AND SHE APOLOGETICALLY EXITED IMMEDIATELY. THE MAIN CAUSE WAS THE SIMULTANEOUS ACTIVATION OF THE SEAT BELT AND STERILE COCKPIT SIGNS, COUPLED WITH A SHALLOW (UNNOTICEABLE?) DSCNT. FLT ATTENDANT DIDN'T REALIZE STERILE COCKPIT WAS IN EFFECT. NO CONFLICT OR ABNORMAL SITS OCCURRED DUE TO THIS.

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.