AD NUMBER: 2017-04-04

PRODUCT: Certain BAE Systems (Operations) Limited Model BAe 146 and Avro 146-RJ series airplanes.

ACTION: Final Rule

SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2012-16-08 for the aircraft listed above.

AD 2012-16-08 required repetitive inspections for bulging, surface anomalies, and cracking of the fuselage skin adjacent to the discharge valves, and repair and application of additional sealant in the affected area if necessary.

This new AD retains the requirements of AD 2012-16-08, expands the applicability, and requires an additional one-time inspection for the presence of water traps/air driers to determine which airplanes must be inspected.

This AD was prompted by reports of cracking and surface anomalies of the fuselage skin at the water trap/air drier unit of the forward discharge valve due to corrosion, and the determination that airplanes on which a certain auto-pressurization modification was incorporated during production were excluded from the applicability of AD 2012-16-08, but are also affected by this condition.

The FAA is issuing this AD to address the unsafe condition on these products.

DATES: This AD is effective March 29, 2017.

FMI: AD