You bet they are- though there is a string of inspections required by Service Bulletin 103 and AD 2011-12-10.
Many existing R22 helicopter owners are concerned about the introduction of a new all aluminum blade, the A016-6, with fancy round tips. The same style and construction techniques are used as in the R44 and R66 MR Blades as the new A005-7 complete MR blade assembly.
No reason for concern, the old -4 blades are perfectly airworthy as long as they are maintained in accordance with the SB and AD. The big issue is any bond line exposure and associated issues that can lead to corrosion and ultimately de-bonding. As long as owners of the -4 blades keep them painted properly, the blades will fly to TBO.
We have been getting a bunch of questions from customers if RHC has plans to pull the -4 main rotor blades across the entire fleet of R22 helicopters. I will refer to a conversation I had a few months back with Robinson tech support, they state that RHC and the FAA have no plans to pull the -4 blades out of service.
The -4 MR blades are however limited by the same rules as always….12 years or 2200 hours in service. Have peace of mind, your -4 blades will make it to the next overhaul!!!
MIght want to update this. They want to retire all the -4’s in five years http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgADNPRM.nsf/0/AE78FBBFD544947786257B1D004F73D2?OpenDocument
Matt- thanks for the catch. Yes, we have been following the progress of this AD carefully.