EASA AD US-2023-24-04
Engine / Engine Controls - Electronic Control Unit / Software - Replacement
Summary
The Federal Aviation Administration's Airworthiness Directive 2023-24-04 is a final rule addressing Honeywell International Inc. Model AS907-1-1A and AS907-2-1G engines. It targets an unsafe condition caused by compressor surges during takeoff climb through steep temperature inversions, which can lead to loss of engine thrust control. This directive mandates software updates or ECU replacements to mitigate this risk.
What Changed
This new Airworthiness Directive requires operators of Honeywell AS907-1-1A engines to either update the ECU software to version AS907_1001 or replace the ECU with an eligible unit. For AS907-2-1G engines, the AD mandates replacement of certain ECUs with eligible units. The directive clarifies compliance times, software version numbers, and cost estimates based on stakeholder feedback.
Why It Matters
This AD is critical for maintaining engine performance and safety during takeoff, especially under challenging atmospheric conditions like temperature inversions. Operators and maintenance organizations must address the ECU software or hardware issues to prevent compressor surges that could cause dual engine thrust loss, potentially compromising climb performance and obstacle clearance. Compliance ensures continued airworthiness and reduces the risk of in-flight engine control failures.
What To Do
Affected operators must comply with the AD by January 10, 2024. For AS907-1-1A engines, they must either update the ECU software to the approved version or replace the ECU with an eligible unit within specified compliance times. For AS907-2-1G engines, replacement of two ECUs per engine with eligible units is required within the compliance timeframe. Operators should review the FAA docket for detailed instructions and plan maintenance accordingly.
AI-generated summary from official EASA source document. Always verify against the original.