Airworthiness Directive · Amendment 39-16720 · Flight controls
The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER Series Airplanes
This AD applies to The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes, certificated in any category; as identified in Boeing Service Bulletin 737-27-1289, dated April 7, 2010.
We are adopting a new airworthiness directive (AD) for the products listed above. This AD requires repetitive testing of the stabilizer takeoff warning switches, and corrective actions if necessary. This AD was prompted by reports that the warning horn did not sound during the takeoff warning system test of the S132 "nose up stab takeoff warning switch." We are issuing this AD to detect and correct a takeoff warning system switch failure, which could reduce the ability of the flightcrew to maintain the safe flight and landing of the airplane.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
Within 6 months after the effective date of this AD, test the stabilizer takeoff warning switches, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-27-1289, dated April 7, 2010. Repeat the test thereafter at intervals not to exceed 750 flight hours. Accomplishment of the repetitive tests required by paragraph (g) of this AD terminates the operational and functional checks of the takeoff configuration warning system required by paragraph A., required item 3 (“Elevator out of Green Band switches”) of AD 88-22-09.
If any stabilizer takeoff warning switch fails the test required in paragraph (g) or (h) of this AD, replace the stabilizer takeoff warning switch with a new switch and test the new switch before further flight, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-27-1289, dated April 7, 2010. Within 750 flight hours after replacement of any switch, test the replaced switch, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-27-1289, dated April 7, 2010; and repeat this test on the replaced switch thereafter at intervals not to exceed 750 flight hours.
