What is the Ram Air Turbine (RAT) used for on a narrowbody?

• A. Ram Air Turbine (RAT) provides emergency electrical power when primary sources fail.
• B. RAT is used to generate hydraulic power.
• C. RAT powers environmental control packs.
• D. RAT is a backup oxygen source.

Answer: (A)

The key idea is that this device acts as a backup power source for the aircraft’s essential systems when the main electrical sources fail. The Ram Air Turbine is a small turbine that deploys into the airstream and drives a generator to supply electrical power to critical buses and avionics during an electrical power failure. This keeps essential equipment—like flight instruments, communication, and basic flight controls—operational long enough for the crew to handle the situation and land safely.

It’s not used to generate hydraulic power on most narrowbody designs, it isn’t a source for environmental control packs, and it isn’t a backup oxygen supply. Those systems have different, separate power or supply arrangements, while the RAT’s primary role in this context is emergency electrical power.