Need Failure Mode Simulation for DOC testing

In order to meet the requirements of the DOC for testing in MOC Section 8, we need the ability to simulate failures in the following items:

- Need to simulate fail the transmitter so the PFST fails, and the operator is provided indication of this failure. This has to be done on the ground, and in the air.
- Need to simulate UAS unable to recover from uncontrolled descent (7.7.1.2.1) and loss of control of flight trajectory (7.7.1.2.2)
- Need to simulate loss of GPS position from the GPS. May not need any action. (on ground test, easily done with No Fix)

The issue names PFST transmitter failure, uncontrolled descent, loss of flight trajectory control, and GPS No Fix simulation, but provides no files, tests, or entry points. Start by locating the existing failure-handling and test mechanisms for these behaviors, then define how each failure is triggered and what operator indication or test result is expected.

Written by the indexing model from the issue text.