If the automatic temperature control feature of an A/C pack malfunctions, what can the pilot do?

• A. Select the MAN switchlight for that pack and use the HOT/COLD toggle to adjust the temperature valve.
• B. Disconnect the pack from electrical power.
• C. Vent cabin pressure to relieve excess temperature.
• D. Recycle the air through the other pack.

Answer: (A)

When automatic temperature control fails in the A/C packs, you can take direct control of the affected pack by switching it to manual mode and adjusting its output yourself. Put that pack into manual operation by selecting the MAN switchlight for it, then use the HOT/COLD toggle to move the temperature valve. This directly changes how much hot versus cold air the pack delivers, allowing you to stabilize cabin temperature without relying on the failed automatic system.

Other options wouldn’t fix the issue: disconnecting the pack from electrical power would shut the pack down and cut ventilation; venting cabin pressure is unsafe and not a fix for temperature control; recycling air through the other pack addresses airflow but doesn’t resolve the malfunctioning pack’s temperature control.