EASA AD CF-2023-53: Electrical Power — Transformer Rectifier Unit (TRU) Fan Inoperative | RegNotify

Airworthiness DirectiveEASA AD CF-2023-53

Electrical Power — Transformer Rectifier Unit (TRU) Fan Inoperative

Published: Jul 25, 2023
Effective: Jul 28, 2023
Deadline: Jul 28, 2026

Bombardier BD-700 2A12

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

What to do

Operators of affected Bombardier BD-700-2A12 aircraft must replace the TRU2 unit with the updated part number within 1500 flight hours or 3 years from the effective date of July 28, 2023, whichever occurs first. The replacement must follow the instructions in Bombardier Service Bulletin 700-24-7507 Revision No. 01 or later approved revisions. Compliance teams should also verify if the replacement was done earlier under the basic issue of the service bulletin to receive credit.

Summary

Canadian Airworthiness Directive CF-2023-53 addresses an electrical power issue related to the Transformer Rectifier Unit (TRU) fan on Bombardier Inc. model BD-700-2A12 aircraft, serial numbers 70006 through 70166. The directive mandates corrective action to prevent overheating and potential cascading failures of TRUs. This AD ensures improved safety by requiring replacement of a specific TRU unit with an updated version that includes a corrected fan and monitoring circuit.

What changed

CF-2023-53 introduces a new requirement to replace TRU2 Part Number G02404521-001 with Part Number G02404521-003. This replacement incorporates corrections to the fan and its monitoring circuit to detect fan failures that were previously undetectable. The directive also provides credit for prior replacements done according to an earlier Bombardier service bulletin.

Why it matters

This directive is critical for aviation professionals because an inoperative TRU fan can cause overheating, triggering load shedding and potential automatic disconnection of the TRU, which risks electrical system failures. Operators and maintenance teams must address this to maintain aircraft electrical system reliability and comply with Canadian Aviation Regulations. Failure to comply could lead to unsafe flight conditions and regulatory penalties.

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