EASA AD 2011-0168R1
Lights — Instrument Lighting Display Brightness — Modification
Summary
EASA Airworthiness Directive 2011-0168R1 is a regulatory update addressing instrument lighting display brightness issues on Airbus Helicopters Deutschland GmbH EC 135, EC 635, and MBB-BK117 C-2 helicopters equipped with optional night vision goggle (NVG) systems. The directive mandates modifications to the electrical wiring in the overhead panel to prevent overheating of diodes in the NVG system, which can cause sudden maximum brightness of critical flight displays. This AD ensures continued safe operation by correcting a lighting system fault that could impair pilot visibility.
What Changed
This revision of EASA AD 2011-0168 limits the applicability by excluding MBB-BK117 C-2 helicopters equipped with the optional NVG system installed in-service according to later service bulletin revisions. It also introduces editorial changes for clarity and standardization without altering the original requirements. The AD retains the original wiring modification and flight manual amendment requirements.
Why It Matters
This AD is critical for aviation professionals because it addresses a safety risk where instrument lighting could suddenly become excessively bright, potentially impairing pilot vision and leading to loss of control. Operators and maintenance teams must ensure compliance to maintain aircraft airworthiness and avoid operational restrictions. The directive also clarifies which helicopters are affected, helping compliance teams focus resources appropriately.
What To Do
Operators must amend the Rotorcraft Flight Manual Supplement before the next night flight in NVG mode after 30 November 2010 and inform flight crews accordingly. Within 18 months after 16 September 2011, they must perform the required electrical wiring modification in the overhead panel following the specified Airbus Helicopters service bulletins. After modification, the flight manual changes must be removed before the next flight.
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