Advanced short-runway airliners and large commercial tiltrotors could boost the capacity of the U.S. air transport system without impacting conventional aircraft operations, once the FAA’s NextGen airspace system is fully implemented.

That’s the conclusion of a NASA-funded study into the integration of advanced vehicles into NextGen completed by air-traffic management specialist Sensis. A team led by Raytheon has completed a similar 18-month study.

NASA asked the two teams to study the impact on capacity, delays, the environment and safety of introducing five classes of advanced aircraft into the NextGen airspace system: 737-sized cruise-efficient short-takeoff-and-landing (CESTOL) airliners, 100-passenger tiltrotors, unmanned aircraft, very light jets (VLJ) and supersonic transports.

The modeling and simulation studies showed CESTOL and tiltrotor aircraft would be big beneficiaries of NextGen, says Matt Burke, director of strategic initiatives for advanced development at Sensis. This is because of NextGen’s ability to manage multiple independent, deconflicted approaches to an airport, he says.

Previous efforts to integrate STOL aircraft and rotorcraft into commercial operations at major airports have foundered on the current airspace system’s inability to accommodate their steeper glideslopes and slower approaches without impacting operations by conventional aircraft, he says. When fully implemented, NextGen would automate the process.

Within NextGen, the Sensis study found, CESTOL and tiltrotor aircraft could add significant capacity by serving underused airports and runways in dense metroplex areas, flying arrivals and departures that are procedurally separate from conventional traffic routes. There are several airports in the New York and Washington areas, Burke says, with enough room for large helipads able to accommodate tiltrotors.

Cautioning that the results depended on the assumptions made, Burke says the study showed little impact from VLJ operations on capacity and delays at major airports. But the study assumed the VLJs would operate into nearby regional and smaller airports, he says. Similarly, the UAV business model chosen by the team was a FedEx-style hub-and-spoke cargo operation flown by Cessna Caravan-sized unmanned aircraft and serving smaller airfields, so avoiding any impact on major airports.

Burke says the NASA study was intended to highlight any gaps in NextGen planning that could preclude the introduction of advanced vehicles at some time in the future. “We found some holes in the [NextGen] Joint Planning and Development Office’s concept of operations, but no constraints – nothing that could stop one of the vehicles operating.”

Artist's concept: Aviation Week & Space Technology