Airworx says they are approved, 4 weeks out. C&B in South Dakota has an approved carbide surface but I couldn’t find a good phone number for them. The plane really never sat. Its last teardown was 200 hours before I bought it. I have flown it another 803 hours in 6.5 years, always in a hangar at home. Before my ownership it sat outside at Palo Alto. The problem was that lifter was ground and an ECI rebuilt. Anyone considering a top overhaul should ship a new set to Airworx before it’s taken apart. Learned a life lesson. Sent from my iPhone using Tapatalk