Means to discreetly notify a flightcrew.
Except for all-cargo operations as defined in § 110.2 of this chapter, after October 15, 2007, for all passenger carrying airplanes that require a lockable flightdeck door in accordance with § 121.313(f), the certificate holder must have an approved means by which the cabin crew can discreetly notify the flightcrew in the event of suspicious activity or security breaches in the cabin.
[Doc. No. FAA-2005-22449, 72 FR 45635, Aug. 15, 2007, as amended by Amdt. 121-353, 76 FR 7488, Feb. 10, 2011]