Airworthiness Directive · Amendment 39-21852 · Flight control system
The Boeing Company Airplanes
This AD applies to The Boeing Company Model 737-200 and -200C series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 737-27A1324, dated March 2, 2021.
The FAA is adopting a new airworthiness directive (AD) for certain The Boeing Company Model 737-200 and -200C series airplanes. This AD was prompted by reports of nuisance stick shaker activation while the airplane was accelerating to cruise speed at the top of a climb. Investigation revealed that the activation was caused when the angle of attack (AOA) (also known as angle of airflow) sensor vanes froze and malfunctioned due to insufficient heat in certain AOA sensors to prevent ice buildup. This AD requires inspecting the AOA sensors for certain part numbers or vane shapes, and replacing any affected AOA sensor with a new or serviceable sensor. The FAA is issuing this AD to address the unsafe condition on these products.
For airplanes identified as Group 2 in Boeing Alert Service Bulletin 737-27A1324, dated March 2, 2021: Within 120 days after the effective date of this AD, inspect the AOA sensor, using a method approved in accordance with the procedures specified in paragraph (j) of this AD.
Except as specified in paragraph (i) of this AD: At the applicable times specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-27A1324, dated March 2, 2021, do all applicable actions identified as “RC” (required for compliance) in, and in accordance with, the Accomplishment Instructions of Boeing Alert Service Bulletin 737-27A1324, dated March 2, 2021.
Where Boeing Alert Service Bulletin 737-27A1324, dated March 2, 2021, uses the phrase “the original issue date of this service bulletin,” this AD requires using “the effective date of this AD.”
