Ice and Rain Protection - Air Data Heat System - Modification
- Published
- Effective
- Deadline
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Operators of affected Boeing MD-80 and MD-90 series airplanes must modify the air data heat system as specified in Boeing Alert Service Bulletins MD80-30A132 and MD90-30A031. The modification must be completed by September 10, 2018. If the modified ADH system is inoperable, operators may only continue operation if their MEL includes provisions allowing such inoperability. Requests for alternative compliance methods must follow FAA procedures.
Summary
Federal Register Volume 83, Number 151, Airworthiness Directive 2018-07-04 is a final rule issued by the FAA addressing all Boeing Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), MD-88, and MD-90-30 airplanes. This directive mandates modification of the air data heat (ADH) system to prevent loss of airspeed indication caused by icing conditions. The AD aims to enhance flight safety by ensuring proper activation of the ADH system during icing.
What changed
This new airworthiness directive requires modification of the ADH system so that it activates when the left and right fuel switches are in the ON position. It addresses an unsafe condition reported as loss of airspeed indication due to icing. The AD clarifies operational provisions for inoperability of the modified ADH system under the operator's Minimum Equipment List (MEL).
Why it matters
This AD is critical for aviation professionals because failure to activate the ADH system in icing conditions can lead to unreliable airspeed or altitude indications, increasing the risk of runway overruns during high-speed rejected takeoffs or stall/overspeed events in flight. Operators and maintenance teams must ensure compliance to maintain aircraft safety and regulatory adherence. The directive also impacts maintenance planning due to required modifications and potential requests for alternative methods of compliance.
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