A Unified Approach for Optimal Cruise Airspeed with Variable Cost Index for Fuel-powered and All-electric Aircraft

TL;DR

This paper introduces a unified optimal control approach to determine the best cruise airspeed and flight time for both fuel-powered and all-electric aircraft, considering time-varying cost indices influenced by air traffic control, validated through simulation.

Contribution

It presents the first unified method to optimize aircraft cruise parameters with a time-varying cost index for both fuel and electric aircraft.

Findings

Optimal cruise airspeed and flight time can be effectively computed with variable cost indices.

The methodology adapts to real-time ATC inputs during flight.

Results demonstrate applicability to future all-electric aircraft operations.

Abstract

This paper proposes for the first time a unified optimal approach to solve a direct operating cost (DOC) minimization problem where the cost index (CI) is time-varying. More specifically, the coefficient CI is modeled as a time-varying parameter commanded by Air Traffic Control (ATC). The proposed unified approach relies on the solution of an optimal control problem both for fuel-powered and all-electric aircraft. Furthermore, this paper demonstrates how a variable CI affects the solution of the optimization problem as it presents the equations that allow the computation of optimal constant cruise airspeed and flight time in response to step changes in the CI value. The proposed methodology is validated by a simulated flight scenario. In this scenario the inputs from the ATC are received during flight and the aircraft is required to adjust its optimal airspeed, flight time, and total energy consumption to comply with the operational restrictions imposed by the ATC. The optimal values of airspeed, flight time and energy consumption are computed for both a fuel-powered and an all-electric aircraft, thus enabling applications of the proposed approach to future air mobility all-electric vehicles.