Ram Air Turbine Systems: What Pilots Need to Know
Learn what a ram air turbine is, how RAT systems provide emergency power, and why pilots need to understand their aircraft-specific limitations.
A ram air turbine, often called a RAT, is an emergency power device found on many transport-category aircraft. It is a small wind-driven turbine that deploys into the airstream when the aircraft has lost important sources of normal power.
Most light-airplane pilots will never operate an aircraft with a RAT, but the concept is worth understanding. It is a good example of how larger aircraft build layers of backup power for rare but serious failures.
For the smaller-airplane version of the same systems mindset, review airplane lights and electrical loads and deadstick landing planning.
What a Ram Air Turbine Does
When deployed, the RAT uses the airplane's forward motion to spin a turbine. That spinning motion can drive a hydraulic pump, an electrical generator, or both, depending on the aircraft design.
The goal is not to restore every system. The goal is to keep essential systems alive long enough for the crew to control the aircraft, navigate, communicate, and land.
On some aircraft, a RAT may support emergency flight control hydraulics. On others, it may power an emergency electrical bus. The exact behavior is aircraft-specific.
When It Deploys
In many aircraft, the RAT can deploy automatically after major electrical or engine-driven power failures. There is often also a manual deployment option guarded in the cockpit.
The logic varies. Some systems respond to loss of AC power, loss of hydraulic pressure, or other severe failure combinations. Pilots must know the system for the aircraft they fly, not a generic version from memory.
Once deployed in flight, a RAT often stays deployed until maintenance resets it on the ground.
What It Can and Cannot Power
A RAT has limited output. That is the central point. It may keep critical flight controls, displays, radios, or navigation functions available, but many normal systems may be lost or degraded.
Possible limitations can include:
- Reduced automation.
- Loss of some displays.
- Limited communications.
- Degraded flight control laws or handling.
- Less available hydraulic pressure.
- Reduced anti-ice, pressurization, or cabin services.
- Longer landing distance because braking, spoilers, or reversers may be affected.
The airplane may still be controllable, but it will not feel like a normal flight.
Airspeed Matters
Because a RAT depends on airflow, aircraft speed matters. If the airplane slows too much, RAT output can decrease. This is why emergency checklists may place strong emphasis on pitch, speed, and configuration.
During a serious failure, the priority is still the old rule: aviate, navigate, communicate. Establish control and energy first. Then run the appropriate checklist.
Why Light-Airplane Pilots Should Care
Most training airplanes do not have a RAT. They may have an alternator, battery, vacuum system, standby instruments, or independent ignition, depending on the aircraft.
The RAT lesson still applies: know what happens after the first failure. If the alternator fails, how long will the battery last? If a vacuum pump fails, which instruments are affected? If the electrical system is lost, what still works?
Large aircraft use a RAT as one layer of redundancy. Small-airplane pilots need the same mindset, even if the hardware is different.
That mindset turns a systems lesson into a real emergency plan.
This connects directly to understanding your flight instruments, because backup power matters only if you know which equipment remains usable.
Why It Adds Drag
A deployed RAT sticks into the airstream. That creates drag. In a glide or power-loss situation, extra drag can reduce range.
That does not mean the RAT is bad. The tradeoff is usually worth it because control and essential power matter more than a slightly cleaner airframe. But pilots should understand that emergency configuration affects performance.
Training Value
RAT events are rare, so training usually happens in simulators for aircraft that have the system. That training is valuable because the emergency can be high workload: degraded displays, abnormal checklists, glide planning, ATC coordination, and a different landing configuration.
The best preparation is aircraft-specific study. Know what triggers deployment, what the RAT powers, what it does not power, what airspeed range matters, and what the checklist expects.
Student-Pilot Takeaway
A ram air turbine is a last-resort backup, not a normal operating tool. It turns airflow into limited emergency power so the crew can keep control of the aircraft.
For smaller-airplane pilots, the broader lesson is redundancy. Know what powers your instruments, radios, flaps, gear, and ignition. Every aircraft has a backup story. A good pilot knows that story before the failure.
Official References
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