Approach
Approach turns up in 2 fields: HVAC, aviation. Here is what it means to the people in each one.
Approach in HVAC
The temperature gap between a fluid leaving a heat exchanger and the fluid or condition it is being brought toward.
For a cooling tower, approach is leaving water temperature minus entering air wet bulb, often around 7 degrees F at design. For a chiller condenser, it is condensing temperature minus leaving condenser water temperature; for an evaporator, leaving chilled water minus evaporator saturation. A small approach means good heat transfer, and a creeping approach on a chiller is the classic sign of fouled tubes or low charge.
"Condenser approach on chiller two is up to 6 degrees from 2, the tubes need brushing before summer."
Approach in aviation
The final phase of a flight where an aircraft aligns with the runway for landing.
This critical segment begins when an aircraft leaves its cruising altitude or holding pattern and begins descending toward a specific runway. It involves configuring the aircraft with flaps and landing gear while following a precise vertical and horizontal flight path. Pilots fly either visual approaches by looking out the window or instrument approaches using radio beacons and satellite guidance.
"Tower, heavy jet is established on the ILS approach for runway two-seven right."