EASA AD US-2020-16-51: [Final Rule] Pneumatic - Engine Bleed Stage 5 Check Valves - Inspection | RegNotify

Airworthiness DirectiveEASA AD US-2020-16-51

[Final Rule] Pneumatic - Engine Bleed Stage 5 Check Valves - Inspection

Published: Aug 11, 2020
Effective: Jul 23, 2020
Deadline: Aug 26, 2020

Boeing 737 300 400 500 600 700

AI-generated summary of the official EASA document. Verify against the PDF before acting.

What to do

Operators of the affected Boeing 737 series must inspect the engine bleed air 5th stage check valves on each engine by August 26, 2020, or immediately if the airplane has been in storage for seven or more consecutive days. Any valve that does not pass inspection must be replaced promptly. Comments on the directive are accepted until September 25, 2020.

Summary

The Final Rule titled 'Pneumatic - Engine Bleed Stage 5 Check Valves - Inspection' is an airworthiness directive issued by the FAA for all Boeing 737-300, -400, -500, -600, -700, -700C, -800, -900, and -900ER series airplanes. It mandates inspections and, if necessary, replacement of the engine bleed air 5th stage check valves on each engine due to reports of valves stuck open causing single-engine shutdowns. This directive addresses a critical safety risk related to potential dual-engine power loss.

What changed

This new airworthiness directive introduces mandatory inspections of the engine bleed air 5th stage check valves on all affected Boeing 737 models. If any valve fails inspection, it must be replaced to prevent engine shutdowns. The rule was initially issued as an emergency AD and is now adopted as a final rule with a defined effective date.

Why it matters

This directive is crucial for aviation professionals because corrosion and malfunction of the 5th stage check valves can lead to compressor stalls and dual-engine power loss, posing a severe safety hazard. Operators and maintenance teams must ensure compliance to avoid forced off-airport landings and maintain aircraft airworthiness. It also impacts maintenance planning and resource allocation for inspections and potential replacements.

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