Airworthiness Directives; Airbus Helicopters Deutschland GmbH (AHD) Helicopters
Key claim: Operators of listed Airbus EC135 and EC635 helicopters must update their rotorcraft flight manuals with new emergency, malfunction, and normal procedures because the main-gearbox low-oil-pressure light may not come on if oil is lost.
Abstract
(Rule · Transportation Department, Federal Aviation Administration) The FAA is adopting a new airworthiness directive (AD) for all Airbus Helicopters Deutschland GmbH (AHD) Model EC135P1, EC135P2, EC135P2+, EC135P3, EC135T1, EC135T2, EC135T2+, EC135T3, and EC635T2+ helicopters. This AD was prompted by a determination that in cases of loss of oil from the main gearbox (MGB), the low pressure caution or warning light might not activate. This AD requires revising the existing rotorcraft flight manual (RFM) for the helicopter by incorporating updated emergency, malfunction, and normal procedures. The FAA is issuing this AD to address the unsafe condition on these products.
Why this matters
This AD addresses a cockpit-warning gap on a widely operated light twin helicopter — if main-gearbox oil is lost, the low-pressure light may not illuminate, leaving pilots without a primary cue of an impending gearbox failure. Flight-manual procedure updates are the FAA’s interim mitigation while the fleet continues to operate, and this pattern (procedure change rather than hardware fix) is common for warning-system defects on in-service rotorcraft.