Retractable Undercarriage (RU)Fly faster and more complex aircraft and gain your Retractable Undercarriage endorsement. Manual Propellor Pitch Control (MPPC)The Manual Propeller Pitch Control Endorsement opens up opportunities to fly more sophisticated and higher-performance aircraft. Tailwheel Endorsement Challenge yourself and learn to fly a Tailwheel undercarriage. There are many great aircraft that are tailwheels and the satisfaction is unrivaled.