INTRODUCTION
For decades, aircraft have been managed by hydraulic systems — heavy, flammable, and complex networks of fluid, tubing, and mechanical linkages running throughout the airframe. The aerospace industry has long known this architecture is a liability, but replacing it has required confronting one of the most demanding regulatory and engineering environments on earth. Now, that shift is underway. Power-by-wire technology, built on electromechanical actuators (EMAs), is systematically replacing hydraulic systems across flight control surfaces, landing gear, engine vectoring, and more.
This whitepaper from Averna examines the mechanics and momentum behind all-electric flight — from the Technology Readiness Level (TRL) framework that governs aerospace innovation timelines, to the specific testing disciplines that stand between an EMA design and FAA/regulatory certification. For engineers, test teams, and aerospace OEMs navigating this transition, it maps both the promise and the complexity of getting power-by-wire from the lab to the sky.
YOU WILL LEARN
- Why the aerospace industry has been slow to replace hydraulics — and why that is now changing
- What Power-by-Wire (PBW) technology is and how electromechanical actuators (EMAs) replace hydraulic systems across critical flight functions
- The NASA Technology Readiness Level (TRL) scale and why it can take 15+ years to move a new aerospace technology from concept to certified deployment
- How Airbus pioneered the shift to electrostatic actuators and what it revealed about the path forward
- The four key advantages of PBW systems: safety, maintenance simplicity, environmental impact, and weight reduction
- Why EMAs have historically dominated missiles and drones — and what changed to make them viable for commercial aircraft
- What an “iron bird” is and how it is used to validate actuator integration across a full aircraft simulation
- The difference between validation testing and production/end-of-line (EOL) testing for EMAs — and why each demands a different approach
- What an Acceptance Test Procedure (ATP) report is and why it is legally required before any actuator can be released to the field
- Which aircraft are already leading the all-electric transition — and what still stands between PBW and mainstream aviation adoption
STRATEGIC INSIGHT: The Hydraulic System Is Not Being Improved — It Is Being Replaced
The Weight, Safety, and Complexity Case Against Hydraulics
Hydraulic systems require heavy fluid, extensive tubing, and mechanical shafts running throughout the aircraft. Every additional hydraulic line added to support larger aircraft increases both weight and explosion risk — hydraulic fluid is flammable and toxic to technicians. PBW eliminates the fluid entirely. The result: lighter aircraft, simpler schematics, cleaner integration between avionics and control systems, and a dramatically reduced maintenance footprint. For manufacturers, these are not incremental improvements. They are structural advantages that compound over a 30-year aircraft lifespan.
TRL as the Real Timeline Constraint
The TRL scale — developed by NASA and running from basic concept (TRL 1) to successful field deployment (TRL 9) — explains why even proven technologies take 15 years to reach commercial aircraft. Each level demands documented evidence before progression. Airbus began EMA testing at TRL 4 in the early 1990s; TRL 9 was achieved with the A380 in 2007. That 15-year arc is not a failure of ambition. It is the cost of operating in an industry where a 15-year-old aircraft is still expected to perform at the same standard as a new one.
Testing Is the Bottleneck Nobody Talks About Enough
EMAs must undergo both validation testing and production/end-of-line (EOL) testing before a single unit reaches the field. Validation uses iron bird simulators to run thousands of simulated take-offs and landings under extreme temperatures — capturing real-time torque, force, and control data. EOL testing is performed on every individual unit, requiring load curves, power efficiency metrics, and backlash measurements precise to a hundredth of an inch. The Acceptance Test Procedure (ATP) report documenting all results must be filed with and approved by a national regulatory agency. Without it, the part cannot be sold. Test infrastructure is not a support function — it is a certification gate.
CHALLENGES
Achieving TRL 9 in aerospace can take 15 years even when the underlying technology is sound — the regulatory burden is not a bureaucratic obstacle but a reflection of aircraft longevity expectations and life-safety stakes. EMAs must simultaneously manage heavy static loads (historically the domain of hydraulics) and high-speed precision movements, and balancing gear backlash against efficiency remains a delicate engineering constraint. Simulating accurate aerodynamic force loads in a ground-based test environment requires extremely high-speed control systems that re-create dynamic pressure curves in real time — a test engineering challenge in itself. Production capabilities, battery performance limits, and range constraints continue to slow the rollout of fully electric commercial aircraft at scale.
IMPLEMENTATION / STRATEGY
Aerospace OEMs moving toward PBW architectures need a test strategy that spans the full TRL journey — from lab-level component validation through iron bird integration testing to per-unit production EOL certification. Validation testing and production testing demand different setups, different instrumentation, and different documentation outputs, and both must be designed with regulatory traceability in mind from the start. EOL testers in particular must be built to automatically generate ATP reports, as manual documentation at production volumes introduces error and delays time-to-market. The path to all-electric flight runs through test infrastructure as much as it runs through design.
WHO SHOULD READ THIS
This whitepaper is written for aerospace and aviation engineering teams actively navigating the transition from hydraulic to electric actuation systems — including systems engineers, test and validation leads, avionics integration teams, and certification managers at aircraft OEMs, Tier 1 suppliers, and EMA manufacturers. It is also relevant for engineering directors and technical program managers who need to understand the testing investment required to move PBW technologies through the TRL pipeline to regulatory approval.
FINAL CTA
Download Actuators in Air: Achieving All-Electric Flight from Averna to understand the full arc of EMA certification — from Technology Readiness Levels to iron bird validation and production EOL testing — and what your test strategy needs to include to get there.
