Question E1C08:
[97.213] What is the maximum permissible duration of a remotely controlled station’s transmissions if its control link malfunctions?  

Choices:  
A: 30 seconds  
B: 3 minutes  
C: 5 minutes  
D: 10 minutes    

Correct Answer is  B: 3 minutes  

To comply with FCC rule 97.213(b), a remotely controlled (telecommand) station must have a fail-safe that stops transmissions within 3 minutes if the control link fails.

- Correct answer: 3 minutes (B)
  - Rule: If the control link malfunctions, the station must automatically cease transmitting within 3 minutes.

Why the others are incorrect:
- 30 seconds (A): Too strict; the FCC allows up to 3 minutes, not 30 seconds.
- 5 minutes (C): Exceeds the 3-minute limit in 97.213(b).
- 10 minutes (D): Confuses with the ID interval (97.119). Identification timing does not change the 3-minute shutdown requirement for control-link failure.

Useful rule of thumb:
- For telecommand failure timeout:  
  $$t_{\text{max}} = 3\ \text{minutes}$$

This is a safety/Fail-safe requirement specific to remotely controlled stations to prevent unintended transmissions.