C -4 Aircraft Checkouts/Transitions  Instructors as Certifying  Officials for Student and Remote Certificates  Pilot Proficiency  Professional flight instructors maintain knowledge and skill as instructors and as pilots. The flight instructor is at the leading edge of  the aviation industry’s efforts to improve aviation safety through additional training.$_{ }$ Instructors planning to take the ATP multiengine airplane knowledge test may refer to AC 61-138,  Airline Transport Pilot  Certification Training Program , for further guidanc e. The flight instructor should utilize a plan of action and a written training syllabus based on the appropriate ACS/PTS, and record in  the pilot’s logbook the exact extent of any checkout conducted. This record serves a twofold purpose: it benefits the pilot concerned  and it protects the flight instructor if questions arise later. In the event the instructor finds a pilot’s performance to be insufficient to  allow sign-off, the pilot should be thoroughly debriefed on all problem areas and further instruction scheduled. In some cases, a  referral to another instructor may be appropriate.  For the conduct of an aircraft checkout, it is essential the flight instructor is fully qualified in the aircraft used and thoroughly familiar  with its operating procedures, AFM, and operating limitations. An instructor who does not meet the recent flight experience  prescribed by regulations for the aircraft concerned should not attempt to check out another pilot.  Certificated pilots depend on flight instructors for aircraft checkouts and transition training including high performance airplanes, tail  wheel airplanes, motor gliders, and aircraft capable of flight at high altitudes. The flight instructor who checks out and certifies the  competency of a pilot in an aircraft for which a type rating is not required by regulation accepts major responsibility for the safety of  future passengers. Many newer light airplanes are comparable in performance and complexity to transport airplanes. For these, the  flight instructor’s checkout should be at least as thorough as an official type rating practical test. Other considerations include:  14 CFR  part 61, s ection 61.85(b) and  part 107, section  107.63(b)(1) allow instructors to accept a Student Pilot or Remote Pilot  Application. AC 61-141,  Flight Instructors as Certifying Officials for Student Pilot and Remote Pilot Applicants , has process  details for instructors and applicants.  Aircraft and instrument ratings appropriate to the aircraft being flown need to be listed on the flight instructor’s instructor  certificate as indicated in 14 CFR  part 61, s ection 61.57(d)(2).  ⦁ $_{AC 90-109, Transition to Unfamiliar Aircraft, contains information help plan the transition to any unfamiliar fixed-wing }$ airplanes, including type-certificated (TC) and/or experimental airplanes. 