Sterile switch
 

Does anyone have a definitive answer for the purpose of the 'sterile' switch which I've seen fitted to the forward overhead panel on a 733 ?

It turns a blue light on by the flight deck door. It tells the cabin crew that the flight deck crew are not to be disturbed for non-essential reasons. It would typically be used during critical phases of flight such as final approach and landing.

We don't have such a switch...maybe it's an option. May I order one?:E

Thanks Manc.

It's an option that tended to be found on US aircraft. The ones in our fleet that have it originally came from Continental.

Per my company's SOP, the sterile cockpit concept is observed from the time the cockpit door is closed prior to pushback until reaching 10,000 ft when the seatbelt sign is turned off. In some cases when the situation necessitates that the seatbelt sign should stay ON due to turbulence, the sterile cockpit remains in effect even beyond 10,000 ft.

On top of descent, the seatbelt sign is turned ON. Once again sterile cockpit becomes in effect from 10,000 until seatbelt sign is turned OFF after engine shutdown.

The 10,000 ft window is considered to be the most critical and busiest phase of the flight - pilots monitoring traffic and parameters, calling and replying to ATC calls, etc. All cabin crew are briefed about this sterile cockpit concept to remind them that no unnecessary calls/interference should be made to the cockpit.

Since we are operating airbus planes, we don't have this blue light but use instead the seatbelt sign ON/OFF for this procedure.