Narrative:

It is apparently routine for flight attendants to occupy the vacant pilot seat when one of the pilots is using the lavatory in-flight. Most do this without asking permission. I believe it is neither legal, appropriate or safe to have a non-belted unqualified cabin crew member occupying a pilot's flight seat while in-flight. It is even more inappropriate that most flight attendants simply plop themselves into the temporarily vacant seat without a word spoken to the captain or first officer. This must be changed, and unfortunately I believe our pilots are as much at fault for letting this happen as is the flight service department for not making it clear to flight attendants that cockpit seats are to be occupied in-flight only, repeat, only by qualified pilots. This habit is widespread, as it is now unusual to not have a flight attendant jump into the pilot seat during a lavatory break.

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Original NASA ASRS Text

Title: A B737 PLT IS CONCERNED THAT FLT ATTENDANTS ARE OCCUPYING THE PLT SEAT WHEN PLTS USE THE LAVATORY.

Narrative: IT IS APPARENTLY ROUTINE FOR FLT ATTENDANTS TO OCCUPY THE VACANT PLT SEAT WHEN ONE OF THE PLTS IS USING THE LAVATORY INFLT. MOST DO THIS WITHOUT ASKING PERMISSION. I BELIEVE IT IS NEITHER LEGAL, APPROPRIATE OR SAFE TO HAVE A NON-BELTED UNQUALIFIED CABIN CREW MEMBER OCCUPYING A PLT'S FLT SEAT WHILE INFLT. IT IS EVEN MORE INAPPROPRIATE THAT MOST FLT ATTENDANTS SIMPLY PLOP THEMSELVES INTO THE TEMPORARILY VACANT SEAT WITHOUT A WORD SPOKEN TO THE CAPT OR FO. THIS MUST BE CHANGED, AND UNFORTUNATELY I BELIEVE OUR PLTS ARE AS MUCH AT FAULT FOR LETTING THIS HAPPEN AS IS THE FLT SVC DEPT FOR NOT MAKING IT CLR TO FLT ATTENDANTS THAT COCKPIT SEATS ARE TO BE OCCUPIED INFLT ONLY, REPEAT, ONLY BY QUALIFIED PLTS. THIS HABIT IS WIDESPREAD, AS IT IS NOW UNUSUAL TO NOT HAVE A FLT ATTENDANT JUMP INTO THE PLT SEAT DURING A LAVATORY BREAK.

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.