BAE Systems has won all 10 worldwide active inceptor procurements over the last 25 years, making it the world leader for this flight-critical technology.
More than 25 years ago, we developed the world’s first flight-standard active inceptor flight control system for the F-35, while in 2008, we developed the world’s first Active Parallel Actuation Subsystem (APAS) system — or LinkEdge — for the Chinook helicopter. But our firsts don’t end there.
In 2015, we celebrated another five firsts:
- Embraer KC-390 first flight with our active inceptors
- Gulfstream G600 first flight with our active inceptors
- Boeing MH-47G Chinook first flight with APAS
- Boeing AH-64 Apache first flight with our active inceptors
- Sikorsky CH-53K King Stallion first flight with our active inceptors
But what makes these firsts important? Active Control Side Sticks can reduce cost, improve awareness for the flight crew, and work with fly-by-wire systems to provide tactile cueing in the cockpit — all resulting in increased safety and improved performance.
LinkEdge is suitable for upgrading platforms with new ‘active stick’ technology without the need to go fly-by-wire
But what’s Active without Passive?
An inceptor (or stick) is termed “passive” when there is no active, real-time control feel characteristics or tactile feedback to the pilot from the stick. In this case, the stick passes on the electrical signals to the fly-by-wire (FBW) system, and any tactile feel or resistance is generated by dampers and springs. This type of system reduces complexity, weight, and maintenance, and is a minimum requirement for any FBW system.
“Passive” inceptors are used on modern day fixed-wing military aircraft such as the F-22 Raptor and Eurofighter Typhoon, as well as on civil platforms such as the Airbus family of commercial airliners. For rotary-wing aircraft, both the former RAH-66 Comanche and S92-F/CH148 Cyclone utilize passive sticks. Other controllers equipped with non-moving force sensors have been used, such as on the F-16.
Giving the Pilot Control
Traditionally, aircraft have been controlled through a series of mechanical linkages or cables, directly from the pilot’s inceptor to the aircraft’s control surfaces. To ensure the integrity and reliability of these complex mechanical linkages, their design resulted in heavy construction and required frequent maintenance and rigging. The added weight and high maintenance on the aircraft also translated to extra cost.
In the late 1970s, aircraft technologists began to research and test the concept of replacing mechanical linkages with electrical signalling, leading to the evolution of FBW systems, which are common today in both civil and military fixed-wing aircraft and some rotorcraft. The pilot’s inceptor in an FBW system provides electrical signals to the Flight Control Computer, enabling aircraft control with no direct mechanical link to the surfaces.
For dual cockpit aircraft to be coupled, fairly complex and heavy mechanical linkages between the sticks were still necessary. In addition, pilots’ requests for tactile feedback features were lost when passive FBW inceptors were introduced. This led to the latest evolution of pilots’ controllers, referred to as “active inceptors.”
Active inceptors provide static and dynamic tactile force feedback to the pilot at the grip. Think: the resistance you get from a video game controller when you run into an obstacle in the game. The model dictates the level of resistance the pilot will feel when using the control. Dynamically, it dictates characteristics such as damping, inertia, and stiffness. These features mimic the feel characteristics of any aircraft, and can be particularly useful on trainer aircraft.
The potential uses of active inceptor technology far exceed the simple simulation of feel characteristics and the full range of programmable characteristics.
Of significant importance, especially for dual seat aircraft, is the ability of two active control sticks to be linked. This eliminates the need for the mechanical rigging and the cost and weight of the linking that is required for a passive system.
The flight criticality of active inceptor designs means that they have to achieve very high integrity, reliability, and safety levels. Because of this, redundancy, cross-monitoring, and failure management — which are already common concepts in FBW technology — are part of the active inceptor design.
Active inceptor systems have enhanced safety levels compared to the original mechanical systems they have replaced, while offering vast improved benefits in terms of weight reduction, reduced maintenance, and improved pilot situational awareness.
You want to really fly the future? Our active and passive inceptor systems not only provide increased safety and the ultimate pilot experience, but they do it lighter and with less complexity than traditional systems.
With five first flights for our pilot control technology last year, it’s clear our active and passive sticks are the new, optimal solution in this market. What first will our technology accomplish next? It seems the sky’s the limit!