The ThrustSense autothrottle and the airline technology that finally reached general aviation twins

The ThrustSense autothrottle, built by Innovative Solutions and Support (IS&S) of Exton, Pennsylvania, brings a technology standard in airliners since the 1970s to the general aviation twins that arguably need it most. By automatically managing engine power during critical failures — particularly the lethal Vmc rollover scenario — it closes a human-factors gap that no amount of training can fully bridge. The system is already flying on King Air turboprops and is expanding toward piston twins like the Beechcraft Baron 58.

Why Do Twin-Engine Pilots Need an Autothrottle?

Every Boeing 737 and Airbus A320 has an autothrottle managing power across every phase of flight. Meanwhile, piston twins like the Beechcraft Baron, Piper Seminole, and Cessna 310 have flown for decades with zero automated power management. The pilot’s right hand is on the throttles, left hand on the yoke, feet on the rudder pedals — and if an engine quits during takeoff or initial climb, survival depends on doing the right things in the right order within two to three seconds.

That gap between airline automation and GA capability has persisted for half a century. The ThrustSense system is one of the first products to close it.

What Makes Vmc Accidents So Deadly?

Vmc — minimum controllable airspeed with one engine inoperative — is the speed below which asymmetric thrust from the operating engine overwhelms the rudder’s ability to keep the airplane straight. The airplane yaws, the yaw becomes a roll, and within seconds the aircraft is inverted at low altitude with no chance of recovery.

The NTSB has documented this pattern repeatedly. It is one of the most lethal failure modes in general aviation, and it kills experienced pilots, not just students.

The core problem is that human instinct is exactly wrong. When an engine fails, the natural response is to push the throttles forward and climb away from the ground. In a twin below Vmc, firewalling the good engine maximizes the asymmetric thrust that causes the rollover. The correct response — reducing power on the good engine — is one of the most counterintuitive actions in aviation. Your body screams no. That instinct gap is what IS&S set out to solve.

How the ThrustSense System Works

The ThrustSense autothrottle replaces the conventional power lever assembly with a motorized throttle quadrant. The physical levers look and feel the same, and the pilot can override them at any time by simply grabbing and overpowering the servo — the pilot always wins.

Behind the levers, the system continuously monitors a suite of parameters:

Airspeed
Engine torque and temperature
Propeller speed
Gear and flap position

It builds a real-time model of the aircraft’s position in its flight envelope and manages power accordingly.

During normal operations, ThrustSense handles power settings through takeoff, climb, cruise, descent, and approach, holding target speeds within a few knots while protecting engines from over-torque, over-temperature, and over-speed exceedances. That protection alone extends engine life and reduces maintenance costs.

What Happens During an Engine Failure

The headline feature is the emergency response. When ThrustSense detects a power loss, it reacts in fractions of a second and does two critical things:

Advances power on the operating engine to the maximum continuous setting
Modulates that power based on airspeed relative to Vmc — full power if there’s adequate margin, reduced power if the aircraft is near or below Vmc

The system performs the calculation that a human pilot must execute under maximum stress, flooded with adrenaline, in a two-to-three-second window — and it does it faster and more precisely than any human can. It does not decide whether to continue or abort the takeoff. It does not fly the airplane. It manages the single variable that, if mismanaged, turns a survivable emergency into a fatal one.

Certification History and Aircraft Coverage

IS&S received the first supplemental type certificate (STC) for the Beechcraft King Air 200 series in 2018. The system has since expanded to the King Air 350, 350ER, and several other variants.

The King Air was a logical starting point — one of the most popular turboprops in the world, used for corporate transport, air ambulance, and military training, with a well-documented history of Vmc accidents.

The Beechcraft Baron 58 is on the certification roadmap for piston twin installations. The engineering challenge is more complex than the turboprop version because turboprops use a FADEC (Full Authority Digital Engine Control) that the autothrottle communicates with directly. Legacy Continental and Lycoming piston engines use cable-driven throttle bodies and mechanical fuel injection. IS&S solved this with an electromechanical actuator that attaches to the existing throttle quadrant and drives cables through the same mechanical path the pilot’s hand would use — no engine modifications required.

What Does It Cost?

For a King Air installation, expect approximately $70,000 to $90,000 depending on model and shop. That’s comparable to a major avionics upgrade like a new flight management system or glass cockpit retrofit. For operators already carrying six-figure annual fixed costs, it’s a meaningful but proportional investment — and potential insurance premium reductions for reduced loss-of-control risk could offset part of the expense.

For piston twin installations, IS&S has indicated pricing will reflect the different cost universe Baron owners operate in. No official numbers have been published, but based on system complexity and comparable avionics STCs, a range of $30,000 to $50,000 is a reasonable estimate.

The Bigger Picture: GA Automation Is Accelerating

The ThrustSense autothrottle is part of a broader trend closing the automation gap between airliners and GA aircraft. Garmin’s autoland system, the Skyryse FlightOS fly-by-wire retrofit, and ThrustSense all represent the same shift: bringing flight envelope protection to small aircraft without replacing the pilot.

This trend has implications for training. Multi-engine instruction currently dedicates significant time to Vmc demonstrations and engine-out reactions. If autothrottle systems become standard on twins, the training emphasis could shift from raw stick-and-rudder reaction toward systems management and decision-making — continue or abort, where to land, how to configure for single-engine approach. That mirrors exactly what happened in the airline world when autothrottles became standard.

Honest Concerns Worth Noting

System malfunction risk. Any automated system that moves throttles introduces a potential failure mode. IS&S addresses this with instantaneous manual override — grab the lever and overpower the servo. But pilots must understand the system well enough to recognize and react to a malfunction. That training requirement should not be glossed over.

Automation dependency. If pilots trust the autothrottle to catch Vmc exceedances, vigilance about airspeed and engine monitoring could decline. Airline data suggests properly implemented automation reduces accidents even accounting for complacency effects, but managing this through training and culture remains essential.

Certification timeline. Each new aircraft type requires a separate STC, new flight testing, and new documentation. The piston twin installations are in the pipeline but not yet certified. Baron owners should realistically expect another one to two years before installations become available — and FAA timelines frequently stretch beyond initial estimates.

Key Takeaways

The ThrustSense autothrottle detects engine failures in fractions of a second and automatically manages power on the operating engine relative to Vmc — solving a human-factors problem that training alone cannot fully address
The system is certified and flying now on multiple King Air variants, with piston twin certification (Baron 58) in the pipeline
Installation costs range from $70,000–$90,000 for King Airs and are estimated at $30,000–$50,000 for piston twins, with potential insurance premium benefits
Pilots retain full override authority at all times — grab the throttle and the servo yields immediately
This technology represents one of the most significant safety advances for multi-engine GA flying in decades, part of a broader trend bringing airline-grade envelope protection to general aviation