Document ID: chunk:federal_register_of_legislation:F2016L00389:body:0:p2
Version: federal_register_of_legislation:F2016L00389
Segment Type: other
Provision Reference: 
Character Range: 2981–4225

– If not previously accomplished, before further flight from the commencement date of this AD.
             This AD commences on 5 April 2016.
Background:  The FAA issued Telegraphic Airworthiness Directive (AD) T88-11-51 on May 27, 1988, establishing a minimum engine fan speed (N1) when 737 aircraft equipped with CFM56 engines were operated during flight in or near heavy precipitation. That AD was subsequently superseded by AD T88-13-51, Initial Issue and Revision 1 which raised the minimum N1 limitation to ensure that the engine would continue to operate in the presence of heavy concentrations of rain and hail. CFM developed engine modifications designed to improve the rain and hail ingestion capability of the CFM56, thus permitting the engine to operate in heavy rain and hail at flight idle speed without losing power. As a result, in 1993, AD T88-13-51R1 was superseded by AD 93-05-05, which mandated the incorporation of the engine modification and eliminated the N1 limitation.
             This Amendment makes editorial changes throughout the text to align the previously stated Requirements with FAA AD 93-05-05, which superseded AD 88-13-51R1.

William M. David
Delegate of the Civil Aviation Safety Authority
23 March 2016