The FAA has proposed criteria for certifying a novel automated takeoff system on Embraer’s narrowbody E195-E2.
The Brazilian manufacturer in 2021 applied for a type certification modification to add the Embraer Enhanced Takeoff System (E2TS), which it bills as the first automated setup for commercial passenger jets, to the E195-E2. The regional twinjet is the largest member of Embraer’s second-generation E2 family, designed to seat up to 146 passengers. It obtained triple FAA, European Union, and Brazilian type certification in 2019.
The U.S. regulator on Tuesday proposed special conditions for the E2TS on the E195-E2. It classified the automated system as a “novel or unusual design feature” for which the transport category aircraft airworthiness standards proscribed by the type’s certification are inadequate.
The agency reasoned that because E2TS automatically controls the airplane’s pitch and bank angle without pilot input, additional requirements are necessary to establish a level of safety equivalent to existing standards.
Comments on the proposal are due by November 27. The FAA may modify the special conditions based on reasoning and data provided by commenters. The conditions would establish certification standards for the technology but would not themselves constitute approval for operational use.
What the FAA Proposes
The proposed special conditions are necessary because 14 CFR Part 25 takeoff performance requirements presuppose manual flying.
Existing regulations define rotation speed as that at which the pilot manually raises the nose wheels. According to the FAA, an automated system such as the E2TS is expected to reduce expected variations in rotation speed. But it could still be impacted by “residual” variations due to sensor inaccuracies and system tolerances.
“The current regulations do not take into consideration that the takeoff rotation is being performed by an automatic system, not a human being,” the agency wrote.
The FAA proposes that, accounting for the “maximum expected deviations” in rotation speed allowed by E2TS, E195-E2 takeoff distance with one engine out cannot surpass the corresponding published distance in the aircraft flight manual (AFM).
The maximum expected deviations could be calculated using analysis, simulation, and certification flight tests covering performance, handling quality, and other factors. But they should also reflect actual, in-service variations, which will require Embraer to comply with 14 CFR 25.101 performance requirements.
With both engines operating, takeoff distance would not be allowed to exceed the corresponding AFM distance by more than 1 percent, accounting for rotation speed deviations or in out-of-trim conditions. Unless shown to be negligent, deviations of pitch angle, pitch rate, and other factors influencing pitch rotation dynamics would also have to be accounted for.
Finally, the FAA unsurprisingly proposes that operating the E2TS cannot result in unsafe flight characteristics.
If Embraer modifies any models on its type certificate to incorporate the E2TS or amends it to add other models that use the system, those models would be subject to the same special conditions as the E195-E2.
What Embraer’s E2TS Does
Embraer developed the autoflight function to improve takeoff performance and operational safety. It could potentially allow aircraft to carry additional payload or fuel when operating from shorter runways.
The E2TS is designed to engage at the beginning of the takeoff roll, when thrust levers are advanced to the takeoff go-around (TOGA) detent. Once activated, it will perform the takeoff rotation, initial climbout, and other pitch control functions automatically without pilot intervention.
The system will also control the bank angle and augment directional control during the ground run to minimize heading deviations. Ultimately, the flight crew would be responsible for maintaining the runway centerline.
In the air, the E2TS would use sideslip—which changes based on whether one or both engines are operating—as the reference for providing control.
LATAM, South America’s largest airline group, is the intended launch operator for the automated takeoff system.
In August, Brazil’s Agência Nacional de Aviação Civil (ANAC), which has participated in the system’s development and testing, was reported to be targeting certification in October.
