Document Aliases for Engine Deck Headers

[jdgratz10]

Desired capability or behavior.

The Aviary capability of aliasing the names of variables in the headers of engine decks is not currently in the propulsion or input file documentation. This should be included, along with a notional example of how to use it.

Is your feature request related to a problem? Please describe.

No, this is a request for documentation enhancement.

Associated Bug Report

No response