Section 135.95 - Airmen: Limitations on use of services(a) No certificate holder may use the services of any person as an airman unless the person performing those services-(1) Holds an appropriate and current airman certificate; and(2) Is qualified, under this chapter, for the operation for which the person is to be used.(b) A certificate holder may obtain approval to provide a temporary document verifying a flightcrew member's airman certificate and medical certificate privileges under an approved certificate verification plan set forth in the certificate holder's operations specifications. A document provided by the certificate holder may be carried as an airman certificate or medical certificate on flights within the United States for up to 72 hours.Amdt. No. 135-140, 83 FR 30282, June 27, 2018