AD 2025-04-10

final rule
Data completeness: 70%

Airworthiness Directives; Airbus Helicopters Deutschland GmbH Helicopters

AD Number
2025-04-10
Status
final_rule
Effective Date
Product Category
aircraft
Docket
Docket No. FAA-2025-0212
FR Citation
90 FR 11468

Applicability

TypeManufacturerModelDetails
aircraft Airbus Helicopters Deutschland GmbH Airworthiness Directives; Airbus Helicopters Deutschland GmbH Helicopters
aircraft Aviat Various Airworthiness Directives; Airbus Helicopters Deutschland GmbH Helicopters

Unsafe Condition

Occurrences of emergency off switches, part of the warning unit, were reported to have mechanical failures, particularly getting stuck in intermediate positions or having an untimely change of status, on Model MBB-BK117 helicopters. The same switches are installed on Model EC135 and EC635 helicopters, and further investigations identified a batch of warning units that might be affected by similar issues.

AI-generated summary from the source AD text. Verify against the official source before acting.

Required Actions

Inspecting certain switches on the warning units, and depending on the results, replacing or repairing the warning unit. Installing affected warning units on any helicopter provided the two emergency off switches pass its required check.

AI-generated summary from the source AD text. Verify against the official source before acting.

Compliance Time

Before further flight

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Affected Aircraft

Airbus Helicopters Deutschland GmbH Model EC135 P1, EC135 P2, EC135 P2+, EC135 P3, EC135 T1, EC135 T2, EC135 T2+, EC135 T3, EC635 P2+, EC635 P3, EC635 T1, EC635 T2+ EC635 T3, MBB-BK117 C-2, MBB-BK117 D-2, MBB-BK117 D-3, and MBB-BK117 D-3m helicopters.

AI-generated summary from the source AD text. Verify against the official source before acting.

Source: Official FAA Source ↗

Retrieved: Apr 6, 2026

Rights: U.S. Government Public Domain

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