TBO - time between overhauls, an engine manufacturer's recommended overhaul interval in hours, a rough and not guaranteed guide to life expectancy of an aero-engine before it will need overhaul.
TCA - Terminal Control Area (USA).
TBO Time between overhauls.
t/c ratio Ratio of the thickness (aerodynamic depth) of a wing or other surface to its chord, both measured at the same place parallel to the fore-and-aft axis.
TCAS Traffic-alert and collision-avoidance system.
The company moved the pilot's position from the left seat to the more-traditional right seat; installed a less-expensive, lower-powered engine with a higher TBO; and reduced the gross weight.
As an aside, engines are rated with a "TBO"- Time Before Overhaul. It varies from engine to engine but is usually around 2,000 hours for a General Aviation engine.
Most owners consider an upgrade when their engines reach TBO; in the jet market, that calculation is turned on its head. Resale value of the jet engine as a core is higher when the engine still has time left before TBO.
- High Time engine - With an engine that's within a couple hundred hours of TBO, an airplane is likely to be an orphan until the price is low enough.
- Un-popular type - Some airplanes just never made it in the popularity contest.
A routine 100-hour inspection on "The Yellow Max", my 1976 Cessna 150 revealed that the engine was at TBO, and needed to be either overhauled or replaced.
SMOH - since major overhaul. Term used in aircraft for sale advertisements where engine hours are quoted (see TBO). Also STOH, since top overhaul, TTSN, total time since new; TTAF/E, total time airframe/engine,
SMR - surface movement radar.
Heinlein] TBO Time Between (or Before) Overhaul TSO Technical Standard Order VASI Visual Approach Slope Indicator VMC Visual Meteorological Conditions - flying in conditions at least as good as the minimums required for VFR flight Frequently-Noted ...
See also: Plane, Speed, Airplane, Pilot, Up