Definition
An endorsement-based proficiency check in which a pilot receives instruction and demonstrates competency in the operation of an airplane equipped with conventional landing gear (a main gear forward of the center of gravity and a small wheel under the tail). The checkout covers normal and crosswind takeoffs and landings, wheel landings, and taxiing, and results in a logbook endorsement from an authorized instructor as required by FAA regulation before the pilot may act as pilot in command of a tailwheel airplane.
Plain English
Special training and a signoff a pilot must get before flying an airplane that has a small wheel under the tail instead of a nosewheel. Tailwheel airplanes handle differently on the ground, so the pilot has to prove they can take off, land, and taxi one safely.
Context Anchor
You will encounter this when transitioning from common nosewheel training airplanes to older, aerobatic, bush, or classic airplanes that have a tailwheel.
Derivation
Tailwheel describes the wheel under the tail of the airplane. Checkout comes from the idea of being checked, examined, and cleared as competent before being allowed to operate something on your own.
Why Pilots Care
Tailwheel airplanes handle differently on the ground and can ground-loop if the pilot lacks the required skills.
Intuition Check
Do not read “checkout” as a quick look or a simple rental formality. In aviation, a checkout means hands-on training and evaluation to make sure the pilot can operate that airplane safely.
Example Sentence 1
Before renting the Piper Cub, she completed a tailwheel checkout with the school's senior instructor and received the endorsement in her logbook.
Example Sentence 2
Once the tailwheel checkout was complete, she added the endorsement to her logbook.