EASA AD US-2020-06-19
Navigation - Angle of Attack Sensors - Inspection
Summary
Federal Register Volume 85, Number 96 (May 18, 2020) is a final rule airworthiness directive issued by the Federal Aviation Administration (FAA) addressing certain Boeing Model 727 series airplanes, including 727, 727C, 727-100, 727-100C, 727-200, and 727-200F. The directive targets angle of attack (AOA) sensors that may ice over, causing immobilization of the sensor vanes and resulting in nuisance stick shaker activation during climb to cruise speed.
What Changed
This new airworthiness directive requires a general visual inspection of specified AOA sensors and replacement of affected sensors to prevent ice buildup that can immobilize the sensor vanes. It introduces mandatory compliance actions within 36 months or according to Boeing Alert Service Bulletin 727-34A0247, Revision 1, dated October 1, 2019. The directive does not supersede any previous ADs but aligns compliance times with related AD 2019-24-18.
Why It Matters
This directive is critical for aviation professionals because ice accumulation on AOA sensors can lead to inaccurate sensor data and unintended stick shaker activation, potentially compromising aircraft controllability. Operators and maintenance teams must ensure timely inspections and replacements to maintain flight safety and regulatory compliance. Failure to address this unsafe condition could result in operational disruptions and increased safety risks.
What To Do
Operators of affected Boeing 727 series airplanes must perform a general visual inspection of the AOA sensors and replace any affected sensors within 36 months of June 22, 2020, or sooner if specified in Boeing Alert Service Bulletin 727-34A0247, Revision 1. Compliance must follow the procedures outlined in the service bulletin, with credit given for prior actions done per the original service bulletin. Maintenance and compliance teams should coordinate to schedule and document these actions promptly.
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