FAA Issues Airworthiness Directive for Airbus EC135 Helicopters Over Fuel Cutoff Switch Malfunctions
The Federal Aviation Administration (FAA) has issued a new airworthiness directive (AD) affecting various Airbus Helicopters Deutschland GmbH EC135 models due to malfunctions in emergency fuel cutoff switches.
The measure, which takes effect on March 24, aims to prevent potential in-flight power loss.
Models Affected
The directive applies to the following EC135 and MBB-BK 117 helicopter variants:
✔ EC135P1, EC135P2, EC135P2+, EC135P3
✔ EC135T1, EC135T2, EC135T2+/EC635T2+, EC135T3
✔ MBB-BK 117 C-2, MBB-BK 117 D-2, MBB-BK 117 D-3
According to the FAA, incidents have been reported where emergency switches became stuck in intermediate positions or unexpectedly changed state, which could result in the uncommanded shutdown of one or both engines.
Required Inspections and Repairs
The directive mandates an inspection of the switches in warning units, with mandatory repairs or replacements if any malfunctions are detected.
Additionally, the FAA allows for the installation of specific warning unit models under certain conditions.
Urgent Compliance Requirements
Due to the potential safety risk, the FAA has determined that this directive requires immediate implementation, bypassing the usual public comment period.
✔ Operators must complete the inspection within 55 flight hours or 12 months, whichever comes first.
✔ A switch failure could cause an unintended fuel valve shutdown, which, in extreme cases, could lead to a forced autorotation and potential loss of control.
Estimated Impact and Costs
The FAA estimates that this directive will affect 606 helicopters in the United States.
- Inspection time per aircraft: 30 minutes
- Inspection cost: $43 per unit
- Replacement (if required):
- Labor: 4 hours
- Parts cost: $46,000
- Total cost per affected helicopter: $46,340
Regulatory Justification
The FAA issued this directive based on a prior European Union Aviation Safety Agency (EASA) directive, which also identified the issue and established corrective measures.
Operators have until April 21, 2025, to submit comments on the directive. However, the measures will already be in effect, and the FAA may revise the AD if new technical data justifies changes.
✔ Inspections and repairs must be carried out by certified technicians as per FAA regulations.
✔ Special flight permits are prohibited for affected helicopters, ensuring no aircraft operates without prior inspection.
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