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With Recent AD, Clock Running Out on R44 Astro Fleet

December 10, 2014

Does recent AD spell the end for Robinson’s R44 Astro helicopter fleet?

Robinson R44 Astro

Overview of AD 2014-23-16

On December 5th, 2014 the Federal Aviation Administration issued Airworthiness Directive 2014-23-16 which affects certain part numbered (prior revision) main rotor blades on Robinson  R22 and R44 helicopters.   Read the Rotorcorp AD summary here. Publication of AD 2014-23-16 came after an extensive and lengthy public comment period  throughout the Notice of Proposed Rule Making (NPRM) which started almost two full years before the final ruling was released this week.  The most pronounced concerns expressed during public comment wereby owners and operators of the nearly three-hundred strong fleet Robinson’s R44 Astro Helicopters who viewed the potential of the AD to ground their helicopters.

Impact of AD on R44 Astro Helicopter

The revised AD calls for a continuation of visual inspection and “tap testing” at prescribed intervals to detect potential skin separation along the bond line of affected main rotor blades, but adds new terminating action which requires installation of the latest revision C006-7 main rotor blades within 5 years of the AD effective date- by no later than January 9th, 2020.

The specified terminating action of the AD creates a unique and potentially costly compliance scenario for R44 Astro helicopters.  Introduced in 1993, the Astro is the first in Robinson’s R44 line of helicopters and features manual flight controls whereby flight loads from the rotor blade system are effectively passed  through the the flight control system to the operator.  Later R44 Raven I and Raven II models utilize hydraulically assisted flight controls which dampen the feedback of flight loads to the controls and operator.  The Coo6-7 main rotor blade has a longer chord dimension that the previous C016-2 or C016-5 blade versions and it was determined that the manual flight controls found on the Astro could not handle the additional flight loads generated by the C006-7 blades.

In order to maintain continued airworthiness, R44 Astro’s with manual flight controls must first be retrofitted with hydraulic flight controls in order to accommodate the new C006-7 main rotor blades as terminating action for AD-2014-23-16.   Currently, Robinson Helicopter Company requires that hydraulic retrofit procedures for R44 Astros be completed at the factory in Torrance California, representing a significant additional cost for transportation of the helicopter to and from the factory.  While Robinson has authorized the release of a hydraulic field kit for conversion of Astro’s located overseas to four specific authorized service centers, no field hydraulic retrofit kit is currently available to customers in North America.  Robinson has also restricted the availability of certain key parts specific to the hydraulic conversion in order to prevent unauthorized conversions of Astro helicopters.

Concerns Over Unsafe Compliance Methods

Faced with steep costs and extended time frames  for both AD-2014-23-16 compliance and hydraulic conversions through Robinson-mandated channels, many operators have turned instead to the secondary parts and salvage market to procure necessary components for continued airworthiness.  Additionally, the complex work of hydraulic conversion is frequently being performed by maintenance providers that are outside of Robinson’s network of Authorized Service Centers.  Due to the potential for lower quality components and labor through secondary channels, this development poses obvious and significant safety concerns for Astro operators and the public.  Through Service Letter 49,  Robinson has lessened the financial burden of compliance to a very small number operators affected by  AD 2014-23-16 by providing a fifty-percent discount on blades, but the lack of a readily available field hydraulic retrofit solution remains a large barrier to compliance for Astro owners and operators in North America.  If overseas service centers have been authorized to perform these upgrades and increase the safety of the fleet, the same solution should be made available to “local” owners.

Related:

FAA Announces 5 Year Retirement on R22 and R44 Main Rotor Blades


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