Airworthiness DirectiveEASA AD US-2020-01-11

Air Conditioning - Temperature Control Valve / Control Cabin Trim Air Modulating Valve - Replacement

Published: Jan 21, 2020
Effective: Feb 21, 2020
Deadline: Feb 21, 2020
Replaces: 2017-12-07

Boeing 737 800 900 900ER

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

What to do

Operators of affected Boeing 737-800, -900, and -900ER airplanes must replace the left temperature control valve and control cabin trim air modulating valve within 60 months after July 20, 2017, or by February 21, 2020, whichever is applicable. Additionally, they must perform inspections or records checks to identify affected parts and replace them as required. Compliance must be documented and performed according to Boeing Alert Service Bulletin 737-21A1203 dated June 8, 2016.

Summary

Airworthiness Directive 2020-01-11 is a final rule issued by the Federal Aviation Administration (FAA) addressing certain Boeing 737-800, -900, and -900ER series airplanes. It mandates the replacement of the left temperature control valve and control cabin trim air modulating valve to prevent in-flight failures that could cause excessive temperatures in the flight deck or passenger cabin. This directive updates and expands the applicability of the previous AD 2017-12-07.

What changed

This AD supersedes AD 2017-12-07 by retaining its original valve replacement requirements, expanding the applicability to include additional Boeing 737-800, -900, and -900ER airplanes, and adding a new requirement for certain airplanes to identify and replace affected parts. It clarifies compliance language and addresses potential installation of affected parts on airplanes outside the original scope.

Why it matters

This directive is critical for aviation professionals because failure of the specified valves can lead to cabin and flight deck temperatures exceeding 100 degrees Fahrenheit during cruise, potentially impairing flightcrew performance and jeopardizing safe flight and landing. Operators and maintenance organizations must ensure compliance to maintain airworthiness and safety standards. It also affects parts management and inspection protocols for affected aircraft fleets.

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