Federal Aviation Administration August 15, 2017 – Federal Register Recent Federal Regulation Documents

We propose to adopt a new airworthiness directive (AD) for all The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. This proposed AD was prompted by reports of crack indications in the right wing upper aft skin, originating from fastener holes common to the rear spar upper chord. This proposed AD would require repetitive inspections for cracking of the wing upper aft skin, and applicable on-condition actions. We are proposing this AD to address the unsafe condition on these products.

We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 737-200, -300, -400, and -500 series airplanes. This proposed AD was prompted by reports of cracks in the frame web adjacent to the air-conditioning support brackets. This proposed AD would require an inspection for any air conditioning bracket assembly or intercostal, and depending on the results, repetitive inspections for cracking of certain locations and applicable on-condition actions. We are proposing this AD to address the unsafe condition on these products.

We propose to supersede Airworthiness Directive (AD) 2012-12- 05, which applies to all The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. AD 2012-12-05 currently requires repetitive inspections for cracking under the stop fittings and intercostal flanges and for cracking of the intercostal web, attachment clips, stringer splice channels, frame, reinforcement angle, shear web, frame outer chord and inner chord; a one-time inspection to detect missing fasteners; repetitive inspections of the cargo barrier net fitting for cracking; repetitive inspections for cracking of the stringer S-15L aft intercostal; and repair or corrective action if necessary. Since we issued AD 2012-12-05, we have received reports of additional cracking in locations not covered by the inspections in that AD. For certain airplanes, this proposed AD would add new repetitive inspections of certain areas of the frame inner chord, and applicable on-condition actions. We are proposing this AD to address the unsafe condition on these products.

We propose to supersede Airworthiness Directive (AD) 2015-09- 07, which applies to all The Boeing Company Model 787 airplanes. AD 2015-09-07 requires a repetitive maintenance task for electrical power deactivation. Since we issued AD 2015-09-07, Boeing has developed new software for the generator control unit (GCU) that addresses the software counter overflow anomaly that prompted the issuance of AD 2015-09-07. This proposed AD would require installing the new GCU software. This proposed AD would also remove certain airplanes from the applicability. We are proposing this AD to address the unsafe condition on these products.

We propose to supersede Airworthiness Directive (AD) 2016-02- 01, which applies to certain Airbus Model A320-211, -212, and -231 airplanes. AD 2016-02-01 requires repetitive inspections to detect cracks of the pressurized floor fittings at a certain frame, and renewal of the zone protective finish or replacement of fittings with new fittings if necessary. AD 2016-02-01 also provides an optional modification that is terminating action for the repetitive inspections. Since we issued AD 2016-02-01, the manufacturer conducted an additional fatigue analysis of cracking of the pressurized floor fittings and determined that the optional modification should be a required action. This proposed AD would retain the requirements of AD 2016-02-01, and would require accomplishment of the modification. This proposed AD is intended to complete certain mandated programs intended to support the airplane reaching its limit of validity (LOV) of the engineering data that support the established structural maintenance program. We are proposing this AD to address the unsafe condition on these products.