Brush up on your aviation vocabulary

Question: Could you explain takeoff thrust deration? I was on a Delta

767-300 flying to Tokyo Narita from Honolulu and the pilots said that the thrust was derated to 50C. What exactly does this mean?

— Christopher V., Honolulu Answer: Thrust deration is a way to increase engine life. Jet engines experience the most wear during highthrust demands. If lower thrust settings can provide the necessary thrust, it saves significant engine wear.

Pilots determine the climb performance requirements for every takeoff, and often there is excess thrust available. They can then determine the maximum temperature that a takeoff could be made at the anticipated weight. In your flight’s case, the outside temperature may have been 20 degrees Celsius, or 20C (68 degrees Fahrenheit), but the engine was only told to produce thrust as if it were 50C

(122 degrees Fahrenheit).

Q: I understand that a system called ADS-B OUT is to be mandated for all jet aircraft in the year 2020. Can you explain how it works? — William Confoy, Naples, Fla.

A: Automatic Dependent Surveillance – Broadcast (ADS-B) is a special transmitter installed in airplanes to provide instant information to airtraffic controllers and other aircraft. There are two components in the system: the transmitter (out) and the receiver (in). In the future, airplanes will broadcast continuous updates of their position, altitude, speed, heading and registration. ADS-B does not have the limitations of traditional radar and is not affected by weather.

John Cox is a retired airline captain with US Airways and runs his own aviation safety consulting company.