2. J Control Theory Appl 2011 9 (1) 28–33
DOI 10.1007/s11768-011-0242-9
Application of wireless sensor networks to aircraft
control and health management systems
Rama K. YEDAVALLI, Rohit K. BELAPURKAR
Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus Ohio 43210, U.S.A.
Abstract: Use of fly-by-wire technology for aircraft flight controls have resulted in an improved performance and
reliability along with achieving reduction in control system weight. Implementation of full authority digital engine control
has also resulted in more intelligent, reliable, light-weight aircraft engine control systems. Greater reduction in weight can
be achieved by replacing the wire harness with a wireless communication network. The first step towards fly-by-wireless
control systems is likely to be the introduction of wireless sensor networks (WSNs). WSNs are already finding a variety
of applications for both safety-critical and nonsafety critical distributed systems. Some of the many potential benefits of
using WSN for aircraft systems include weight reduction, ease of maintenance and an increased monitoring capability. This
paper discusses the application of WSN for several aircraft systems such as distributed aircraft engine control, aircraft flight
control, aircraft engine and structural health monitoring systems. A brief description of each system is presented along with
a discussion on the technological challenges. Future research directions for application of WSN in aircraft systems are also
discussed.
Keywords: Wireless sensor networks; Distributed turbine engine control; Fly-by-wireless; Aircraft engine health
monitoring; Aircraft structural monitoring; Communication constraints
1 Introduction
A typical commercial/military aircraft consists of a
number of safety-critical systems, such as aircraft engine
control system, aircraft flight control systems and nonsafety
critical systems, such as structural and engine health moni-
toring systems, aircraft cabin environmental control system,
inflight entertainment system, etc. These systems demand
a large number of real-time sensors for their optimal op-
eration. Current systems, which are based on wired con-
nections, are complex, difficult to route, heavy and prone
to damage and degradation due to wear. The Airbus A380,
for instance, has over 300 miles of cables consisting of ap-
proximately 98,000 wires and 40,000 connectors [1]. Ca-
ble routing is quite a complex task, as for example, the
power cable and electrical signal cable should be physically
separated to avoid electrical interference and can hinder air-
line customization during manufacturing. Also, inaccessi-
ble sensor access point locations and harsh environmental
conditions impose physical restrictions on the use of a wire
harness. This results in the degradation of wiring causing
catastrophic failures. For example, according to a U.S. Navy
report, 6 aircraft were lost due to electrical failure over a 10
year period, about 78 aircrafts are made nonmission capa-
ble due to wiring faults each year and wiring faults cause
more than 1000 mission aborts each year [2]. Replacement
of the current wire harness-based sensors with a wireless
sensor network (WSN) can help to achieve the goal of in-
creasing the number of sensors as well as increasing the
system redundancy. It will also reduce the aircraft system
weight and lead to improved fuel efficiency and reduced
carbon emissions. Replacing the physical cabling by wire-
less connections also offers significant benefits in flexibility,
interoperability, mass reduction and improved robustness.
Use of WSN also enables reduction in direct costs, mainte-
nance cost and obsolescence costs. As most of the current
sensors have double/quadruple redundancy in the form of
sensor hardware and wire harnesses, the use of WSN can re-
sult in huge weight savings. In a recent study, it was shown
that the use of a wireless communication network can re-
sult in 90 lbs. weight reduction of Cessna 310R control sys-
tems, which increases its range by around 10%. Also, in the
same study, assuming only a 50% wire reduction, 267 lbs.
weight saving was shown to be achieved for an SH 60 mili-
tary helicopter control system [3]. Fig. 1 shows the approx-
imate locations of a few typical sensors required for aircraft
flight control systems. As seen in the figure, the sensors are
sparsely located increasing the wire harness length.
Fig. 1 Typical sensor locations of a commercial aircraft [4].
Received 18 October 2010.
c South China University of Technology and Academy of Mathematics and Systems Science, CAS and Springer-Verlag Berlin Heidelberg 2011
3. R. YEDAVALLI et al. / J Control Theory Appl 2011 9 (1) 28–33 29
This paper aims to discuss the various applications of
WSN to aircraft control systems along with addressing the
key technical challenges for their successful implementa-
tion. Future research directions for WSN-based aircraft sys-
tems will also be identified in this paper. The paper is orga-
nized as follows. In Section 2, we will briefly discuss the ap-
plications of WSN for aircraft control systems, specifically
for flight control and aircraft engine control of commer-
cial/military aircrafts and unmanned aerial vehicles (UAVs).
This will be followed by a discussion on the use of WSN for
aircraft engine maintenance & fault diagnostics and also for
aircraft structural health monitoring. Technical challenges
for implementation of WSNs for aircraft systems will be
discussed in Section 3. Finally in Section 4, we will con-
clude this paper with a discussion on the future research di-
rections for aircraft control and health management systems
based on WSNs.
2 Application of WSNs for aircraft systems
WSNs consist of a cluster of spatially distributed in-
telligent sensors designed to monitor a physical parame-
ters, such as vibration, temperature, strain, pressure, etc.
Each sensor node within the network performs the function
of sensing, data processing and wireless data transmission
and is powered by an individual power source. Use of mi-
croelectromechanical systems (MEMS) technology enables
production of low-cost, low-power multifunctional sensors
having very small size and light weight. The concepts, ap-
plications and research issues for applications of wireless
sensor networks are widely discussed in [5,6]. Wireless sen-
sor networks for aerospace applications such as space struc-
tures, spacecraft and ground testing equipment was studied
in [7]. Aircraft systems can be broadly classified as safety-
critical systems and nonsafety critical systems. Failures in
safety-critical aircraft systems are determined unacceptable
and could result in loss of life, damage to the environment
or significant damage to the aircraft. Safety-critical systems
which can benefit from the use of WSN are engine con-
trol systems and flight control systems for both commer-
cial/military aircraft as well as for UAV.
2.1 Distributed aircraft engine control
The present aircraft engine control systems are based on
a centralized architecture in which all the sensors and ac-
tuators are individually connected to the engine controller,
known as full authority digital engine control (FADEC).
Heavily shielded analog wire harnesses are used for these
point-to-point connections between sensor/actuator nodes
and FADEC. Thermal as well as mechanical shielding of the
current centralized engine control systems imparts a heavy
weight penalty. Also, the current centralized architecture
has a high obsolescence cost as well as a high maintenance
cost. Before implementing WSN for aircraft engine control,
an intermediate step is to move towards a distributed control
architecture. In distributed engine control (DEC), the func-
tions of FADEC are distributed at the component level. Each
sensor/actuator is replaced by a smart sensor/actuator. These
smart modules include local processing capability to allow
modular signal acquisition and conditioning, and diagnos-
tics and health management functionality. Dual channel dig-
ital serial communication network is used to connect these
smart modules with FADEC. Fig. 2 shows the schematic of
FADEC based on distributed control architecture.
Fig. 2 FADEC based on distributed architecture.
Distributed engine control allows the implementation of
advanced engine control technologies, for example, active
clearance control, active stall and surge control, active com-
bustion control and adaptive/intelligent control techniques
which will improve aerothermodynamic efficiency, lower
emissions and also help to reduce the control system weight.
The distributed control approach is inherently more pow-
erful, flexible, and scalable than a centralized control ap-
proach. Detailed studies of distributed engine control archi-
tecture can be found in [8∼10]. After successful implemen-
tation of distributed engine control based on fiber optics/
wired communication network, a progression can be made
towards wireless architecture. Initially, WSN can be used
only for the redundant sensors of distributed engine con-
trol system. An ideal distributed engine control architecture,
which will make use of the advantages of WSN, will have
actuators with wired connections in order to provide a se-
cure, reliable control system architecture.
However, there are major technical challenges to the real-
ization of DEC. High temperature electronics, selection of
appropriate communication architecture, and partitioning of
the centralized controller are some of them. As the perfor-
mance of the DEC will be dependent on the performance
of the communication network, selection of the appropriate
communication architecture is very important. Addition of
the serial communication channel will introduce a number
of communications constraints which must be considered
to obtain the desired functionality of the controller. These
constraints include time delays, packet dropouts and bit-rate
limitations. Time delays and packet dropouts can degrade
the controller performance or in worst case, can even desta-
bilize the system. Hence, it is very important to study con-
trol of safety-critical distributed systems under these com-
munication constraints. Decentralized distributed full au-
thority digital engine control was proposed and studied for
stability under time delays and packet dropouts in [11, 12].
As each of the smart nodes will be operating at adverse
environmental conditions including harsh vibrations and
high temperatures, it is necessary to develop reliable elec-
tronics capable of operating at these harsh conditions with
low maintenance requirement. Several commercial off-the-
shelf (COTS) electronic components based on silicon-on-
insulator (SOI) are available which can operate at temper-
atures up to 250 ◦
C. Silicon carbide (SiC)-based electronic
components operating upto 500 ◦
C are one of the promis-
ing technologies that has to be further developed in order to
successfully implement WSN-based distributed engine con-
trol. Also, since this is a safety-critical system, the reliability
of the energy harvesting techniques needs to be further im-
4. 30 R. YEDAVALLI et al. / J Control Theory Appl 2011 9 (1) 28–33
proved. The use of ethernet and wireless technologies for
on-board systems, remote operational monitoring, testing
and control of aircraft engine systems are well discussed
in [13,14].
2.2 WSN for aircraft engine health management
An aircraft engine is a complex system requiring regu-
lar maintenance to ensure flight safety. Engine maintenance,
repair and overhaul (MRO) operations are time consuming
and costly. Hence, in order to improve the time-on-wing
of aircraft engines, it is desired to perform condition-based
maintenance, which uses real-time data to schedule main-
tenance. Although the current maintenance methods do use
sensors for monitoring, data is not stored or transmitted on
a real time basis. This prevents the use of advanced health
monitoring methods which require real time data analysis.
Use of WSN for aircraft engine health monitoring will en-
able implementation of condition-based monitoring algo-
rithms due to availability of real-time data. Each of the
sensor nodes of the WSN will communicate with an on-
board diagnostics and health monitoring system, which will
store the data points for the entire flight. Once on ground,
this data will be transmitted to the maintenance workshop
through wireless communication. This will allow the use of
online as well as offline diagnostic algorithms. Also, since
the data communication will take place using a wireless net-
work, huge infrastructural investments will not be required.
As engine health monitoring is not a safety-critical sys-
tem, certification of WSN-based engine health monitoring
will be less complex than for WSN-based distributed engine
control systems. However, availability of high temperature
electronics will still be one of the major obstacles for suc-
cessful implementation of WSN for engine health manage-
ment. Use of wireless technology for in-flight monitoring
of the temperature of aircraft gas turbine engines was stud-
ied in [15], and reference [16] provides an overview of an
architecture based on WSN for engine health monitoring.
2.3 Fly-by-wireless aircraft flight control system
The aircraft flight control systems consist of flight control
surfaces, cockpit controls, sensors and communication link-
ages between cockpit control and flight control actuators. In
the current fly-by-wire (FBW) flight control systems, flight
control computers determine the control action, which is
transmitted to the control actuator through wire harnesses.
FBW flight control systems improves the handling charac-
teristics of an aircraft by providing high-integrity automatic
stabilization of an aircraft over the entire flight envelope and
for all loading conditions. Triple/quadruple channel redun-
dancy increases the safety and reliability of the flight con-
trol systems. Use of FBW flight control systems not only
reduces the control system weight and reduces maintenance
complexities, but also reduces the pilot workload by per-
forming other functions like stall prevention, etc. Imple-
mentation of FBW enables to limit the aircraft within its
structural and aerodynamic limitations, which is known as,
flight envelope protection. However, these systems still re-
tain the bulky and heavy hydraulic systems for actuating
the control surfaces. Use of electrical or electro-hydraulic
actuators will further reduce the weight, but will also re-
quire additional sensing elements. Intelligent flight control
systems (IFCS) are being developed to safely control the
aircraft in the presence of structural damage or failure dur-
ing flight. This requires development of complex and intelli-
gent control algorithms, which in turn call for an increase in
the number of sensors. Military aircrafts and in particular,
UAVs will greatly benefit from the use of IFCS. Increas-
ing the number of sensors, without a substantial increase in
weight and complexity, is possible only by implementation
of WSN. WSN will enable integration of several systems
into one, for example, the use of WSN for both aircraft en-
gine control and aircraft flight control will allow integra-
tion between flight control and propulsion control, which
can significantly improve performance of military aircrafts
as well as UAVs. Also, there will be greater flexibility for
adding functionality or improving the performance of the
aircraft after initial design and production. One of the other
advantage of using fly-by-wireless flight control systems
based on WSN is that if the pilots or flight deck controls be-
come inoperable or incapacitated, ground-based air traffic
control (ATC) or adjacent military aircraft with necessary
electronics, can control the aircraft.
Flight control systems being safety-critical systems are
of extreme importance to improve the reliability and perfor-
mance of WSN in order to obtain flight certification. Perfor-
mance of WSN in an electromagnetic and radiation environ-
ment and under lightning strikes, which both are prevalent
for commercial/military aircraft and UAVs needs to be stud-
ied. The effect of signal jamming on robustness of WSN
has to be studied in depth, in particular for WSN based
flight control systems of commercial aircrafts. The poten-
tial of WSN-based flight control systems as a backup for
FBW flight control systems also needs to be evaluated. For
high endurance UAV or for UAV having flexible/morphing
wings, a common WSN for both aircraft flight control and
aircraft structural control can greatly improve the flight per-
formance. Optimum bandwidth reduction algorithms for in-
creasing the number of sensors without a significant in-
crease in their power requirement also have to be devel-
oped. Fig. 3 shows fly-by-wireless flight control systems
with WSN.
Fig. 3 Fly-by-wireless aircraft flight control system.
2.4 WSN for aircraft structural health monitoring
Because of the increasing use of composite materials for
aircraft structures, it is necessary to develop novel methods
for aircraft structural health monitoring. Most of the fail-
ures of the laminated composite structures originate with
delamination of layers. In case of metal aircraft structures,
cracks are developed in metal structures which grow over
time leading to failures. For both of these cases, visual in-
spection is not a reliable method for failure detection. This
calls for a vibration analysis-based failure detection method.
Current scheduled aircraft structure maintenance methods
have a high maintenance cost. Several studies have been
5. R. YEDAVALLI et al. / J Control Theory Appl 2011 9 (1) 28–33 31
conducted to develop health monitoring algorithms which
use the data from strain sensors embedded into the com-
posite structure. WSN can be embedded into the composite
structure which will harvest the vibration energy and will
transmit the real-time data to the central health monitoring
unit. These sensors will be used to monitor the internal pa-
rameters like cracks, strain as well as external parameters
like temperature, load, etc. Use of WSN, powered by en-
ergy harvesting techniques will increase the number of sen-
sors as well as their life. Also, real-time data will enable
the use of condition-based maintenance, thereby preventing
catastrophic failure of aircraft structures. Although the use
of MEMS is one of the promising technologies for imple-
mentation of WSN-based aircraft structural monitoring, op-
timum energy harvesting and power management methods
for MEMS sensors have to be further improved. The inte-
gration of sensors and airframe has to be studied; in particu-
lar, the effect on the structural strength of composite materi-
als due to embedded sensors has to be studied. If the sensor
is to be attached on top of the aircraft structure, its interac-
tion with the air flow needs to be investigated. An aircraft
structural health monitoring system based on WSN is de-
scribed in [17] while the structural health monitoring and
reporting (SHMR) system, which uses wireless sensors was
proposed and tested in [18]. Use of WSN for aircraft tire
structural health monitoring is studied in [19].
2.5 Other nonsafety critical systems
Several other nonsafety critical systems that can also ben-
efit from the WSN technology are discussed below.
Aircraft hydraulic monitoring systems
Hydraulic systems play a very important role in powering
primary and secondary flight control systems as well as sev-
eral other utility systems including undercarriage, wheel-
brakes, cargo doors, loading ramps, etc. As failures in hy-
draulic systems may result in loss of maneuverability of
the aircraft, it is necessary to monitor the temperatures,
pressures and flow rates of hydraulic fluids. Condition-
based maintenance methods can also benefit from additional
sensors; for example, filter blockage sensors can help the
ground crew to monitor the condition of filter elements of
hydraulic systems. By replacing the conventional sensors by
WSN, it will be possible not only to display the signals to
the gages in cockpit, but also to the ground servicing per-
sonnel for conducting on-wing aircraft engine maintenance.
Environmental control systems
Environmental control systems (ECS) provide air supply
with optimum humidity and sufficient oxygen concentra-
tion to the passengers and crew and are also used for ther-
mal control of the avionics, fuel and hydraulic systems. The
efficiency of aircraft engines is often decreased due to in-
crease in avionics heat load and due to inefficient air supply
systems. Use of WSN for ECS will help to increase their
reliability as well to improve the efficiency of the aircraft
engines. De-misting, anti-icing systems can also benefit by
the use of WSN.
Emergency systems
Use of WSN for smoke and fire detection systems, emer-
gency lighting systems, passenger address systems, etc. can
help to reduce the weight and wiring complexity of these
systems along with increasing their reliability.
3 Technical challenges
Some of the technological challenges for implementing
safety-critical control systems based on WSN are as fol-
lows.
3.1 Control under communication constraints
The communication between sensors, controllers and ac-
tuators for both distributed engine control systems based on
WSN and fly-by-wireless flight control systems will occur
through a shared bandwidth-limited wireless network. The
use of a wireless communication channel introduces a num-
ber of communication constraints, which have to be consid-
ered during the controller design. Two of such communica-
tion constraints that can have significant effects on the per-
formance of the control system are network-induced time
delays and packet dropouts. The network-induced delay
can be further sub-divided into sensor-to-controller delay,
controller-to-actuator delay, and the computational delay in
the controller. Sensor-to-controller delay and controller-to-
actuator delay will depend on the communication protocol
and can be either constant, time varying or random in na-
ture. Network congestion and channel quality can also re-
sult in random network transmission delay. This delay can
destabilize a system designed without considering the delay
or can degrade the system performance. Packet dropouts in
wireless communication can occur due to transmission er-
rors, long transmission delays or due to packet collisions.
References [20∼23] provide a brief introduction to net-
worked control systems (NCS) and also present a survey on
the recent developments in stability of NCS under commu-
nication constraints. In wireless communication networks,
systems with packet dropouts can be described by stochas-
tic models. The packet dropping of the wireless network can
be modeled as an independent and identically distributed
(i.i.d.) Bernoulli process with a packet dropping probability
(PDP). The maximum PDP that a networked control sys-
tem can tolerate before becoming unstable is called packet
dropout margin (PDM). By improving PDM, which can be
viewed as a measure of stability robustness for a system
with packet dropouts, the stability of networked control sys-
tems with packet dropouts can be improved. A new frame-
work, labeled decentralized distributed full authority dig-
ital engine control (D2
FADEC) was proposed in [11, 12]
and was studied for stability under time delays and packet
dropouts. It was shown that the PDM is dependent on a
closed-loop system matrix structure and that a controller de-
sign based on a decentralized framework further improves
the PDM.
3.2 MAC protocols for wireless control systems
Each sensor node within the WSN has limited energy
and computational resources. In order to make optimal use
of these finite resources, a number of protocols based on
medium access control (MAC) have been developed. These
protocols stress on energy efficiency by reducing the en-
ergy loss due to wireless medium. Several MAC protocols
like carrier sense multiple access (CSMA), IEEE 802.15.4,
IEEE 802.11 are discussed in [24]. Since MAC protocols
focus on energy efficiency and not on reduction in commu-
nication delay or packet dropouts, the performance of con-
trol systems based on these protocols is limited. Research
should be conducted to design MAC protocols which are
not only energy efficient, but also offer high quality of ser-
vice (QoS) in terms of time delay, bandwidth utilization and
6. 32 R. YEDAVALLI et al. / J Control Theory Appl 2011 9 (1) 28–33
data loss due to packet collisions. A very few studies have
focused on this approach. For example, a cross-layer frame-
work for an integrated design of wireless networks and dis-
tributed controllers, which significantly improves the per-
formance and stability of the controller, is presented in [25].
3.3 Dedicated spectrum for wireless aircraft systems
Before implementing WSN for safety critical systems,
it is necessary to ensure that their operability will not be
compromised due to interference between various wireless
networks. The WSNs should not interfere with the aircraft
communication, navigation, and surveillance radio systems
and the intra-aircraft wireless communication. The effect
of crew/passenger portable wireless electronics devices on
WSN also has to be considered during design of WSN.
3.4 Optimum power source
Powering all the sensors using the conventional batter-
ies will not only increase the size and weight of the sys-
tem but will also limit their service life and will require ex-
pensive maintenance. A widely investigated alternative is
to use energy harvesting techniques to generate electrical
power for operating these sensors. WSN can operate almost
maintenance free by use of both energy harvesting meth-
ods and by implementing strict power management [26,27].
Vibration-based harvesting technique is seen as one of the
promising techniques for aerospace applications. Current
vibration energy harvesters are constructed as mechanical
resonators with a transducer element that converts motion
into electricity. They are further divided into three groups
of generators based on their physical transduction princi-
ple: piezoelectric, electrostatic, and electromagnetic. Piezo-
electric vibration-based energy converters deliver the high-
est efficiency at lowest cost and increased life cycle. Piezo
ceramic bimorph beams and MEMS-based piezo resonators
can be used to harvest the energy from vibrations while
bulk ceramic and fiber composites directly bonded to the
aircraft structure can be used to harvest strain energy. As
there is a significant temperature gradient between the cabin
lining and aircraft shell, thermoelectric generators can also
be used to harvest this energy. The operation of these ther-
moelectric devises is based on Seebeck-effect and it has
been shown that a MEMS-based thermoelectric generator
can be efficiently used to generate sufficient power. Use of
MEMS-based steam microturbines to generate electricity
from waste heat of engine exhaust should also be investi-
gated.
3.5 Certification of aircraft wireless systems
Use of wireless communication networks for safety crit-
ical functions of an aircraft require a very high degree of
safety assurance and certification [28]. The Federal Avia-
tion Administration (FAA) has certified a number of on-
aircraft wireless radio frequency (RF) systems which in-
clude wireless smoke and fire detection systems passenger
wireless network systems and cabin emergency lighting sys-
tems with wireless controls. However, all these systems are
nonsafety critical systems and typically operate in an unli-
censed spectrum. Specific regulations for aircraft wireless
systems do not exist and there is a need to develop specific
regulations for such novel applications of WSN. Such regu-
lations are necessary to ensure that there is no interference
between portable electronic devices carried by passengers,
existing airplane radio transmitters and transmitters within
the proposed WSN. There is no worldwide spectrum allo-
cated specifically for fly by wireless systems. The new cer-
tification rules must ensure that WSN are protected against
unauthorized introduction and modification of data, denial
or loss of service, gradual degradation of service and in-
troduction of misleading or false data. The current FAA
regulations expect physical isolation between safety criti-
cal and other communications networks like passenger en-
tertainment networks. Use of WSN for the entire aircraft
makes physical isolation challenging. The new regulations
must also address security threats including safety threats,
business threats, channel jamming attacks, etc.
4 Conclusions
The aerospace industry will greatly benefit from the use
of WSN. These benefits through weight savings, reduction
in subsystems design complexity and improved condition-
based maintenance will directly benefit the airlines in terms
of additional revenues as well as lower operational and
maintenance cost. Use of WSN-based engine health mon-
itoring and aircraft structural health monitoring will enable
the development of safety-critical systems such as WSN
based distributed engine control and fly-by-wireless aircraft
flight control systems. However, there are a few signifi-
cant technical challenges for the successful implementation
of wireless sensor networks. Future research should be di-
rected in addressing the below given technical challenges.
Safety-critical distributed control systems should be
studied for stability and performance under communication
constraints like time delays and packet dropouts. Research
should be conducted to reduce the conservativeness of the
existing random delay stability conditions. The effect of bit-
rate constraints on system stability and performance also
needs to be evaluated.
Research needs to be conducted in the area of informa-
tion fusion of wireless sensor networks for aircraft systems.
Routing protocols should be developed to make effi-
cient use of the limited power supply, limited communica-
tion bandwidth and limited computing power.
Energy harvesting methods needs further improvement
in the terms of efficiency and reliability.
Development of high temperature electronics will en-
able the use of WSN for aircraft engine control and health
monitoring.
New wireless aircraft certification regulations needs to
be developed to address the various security and safety
threats.
A dedicated global spectrum for WSN for aircraft appli-
cations needs to be developed.
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Rama K. YEDAVALLI received his B.S. degree
in Electrical Engineering and M.S. degree in
Aerospace Engineering from the Indian Institute of
Science, India, and Ph.D. degree from the School
of Aeronautics and Astronautics of Purdue Univer-
sity in 1974, 1976 and 1981, respectively. He is cur-
rently a professor in the Department of Mechanical
and Aerospace Engineering at the Ohio State Uni-
versity, Columbus, OH. He is a fellow of IEEE and
a fellow of ASME and an associate fellow of AIAA. He is the recipient
of the O. Hugh Schuck Best Paper Award by the American Automatic
Control Council in 2001. Dr. Yedavalli’s research and teaching interests
include robustness and sensitivity issues in linear uncertain dynamical sys-
tems, estimation and fault diagnostics of propulsion systems, control of
smart structural systems, networked control systems, dynamics and con-
trol of flexible structures, aircraft, spacecraft, automotive, robotic, energy,
and other mechanical control systems. E-mail: yedavalli.1@osu.edu.
Rohit K. BELAPURKAR joined the Ohio State
University, U.S.A. in 2006 and is currently pursu-
ing Ph.D. degree in the Department of Mechan-
ical and Aerospace Engineering. He obtained his
B.S. degree in Mechanical Engineering from Uni-
versity of Pune, India, in 2006 and M.S. degree in
Aerospace Engineering from the Ohio State Uni-
versity, in 2008. His research interests include dis-
tributed aircraft engine control, networked control
systems, time delay systems, decentralized control systems, sensor net-
works, nonlinear control theory, and robust control of safety-critical dis-
tributed systems. E-mail: belapurkar.2@osu.edu.
![J Control Theory Appl 2011 9 (1) 28–33
DOI 10.1007/s11768-011-0242-9
Application of wireless sensor networks to aircraft
control and health management systems
Rama K. YEDAVALLI, Rohit K. BELAPURKAR
Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus Ohio 43210, U.S.A.
Abstract: Use of fly-by-wire technology for aircraft flight controls have resulted in an improved performance and
reliability along with achieving reduction in control system weight. Implementation of full authority digital engine control
has also resulted in more intelligent, reliable, light-weight aircraft engine control systems. Greater reduction in weight can
be achieved by replacing the wire harness with a wireless communication network. The first step towards fly-by-wireless
control systems is likely to be the introduction of wireless sensor networks (WSNs). WSNs are already finding a variety
of applications for both safety-critical and nonsafety critical distributed systems. Some of the many potential benefits of
using WSN for aircraft systems include weight reduction, ease of maintenance and an increased monitoring capability. This
paper discusses the application of WSN for several aircraft systems such as distributed aircraft engine control, aircraft flight
control, aircraft engine and structural health monitoring systems. A brief description of each system is presented along with
a discussion on the technological challenges. Future research directions for application of WSN in aircraft systems are also
discussed.
Keywords: Wireless sensor networks; Distributed turbine engine control; Fly-by-wireless; Aircraft engine health
monitoring; Aircraft structural monitoring; Communication constraints
1 Introduction
A typical commercial/military aircraft consists of a
number of safety-critical systems, such as aircraft engine
control system, aircraft flight control systems and nonsafety
critical systems, such as structural and engine health moni-
toring systems, aircraft cabin environmental control system,
inflight entertainment system, etc. These systems demand
a large number of real-time sensors for their optimal op-
eration. Current systems, which are based on wired con-
nections, are complex, difficult to route, heavy and prone
to damage and degradation due to wear. The Airbus A380,
for instance, has over 300 miles of cables consisting of ap-
proximately 98,000 wires and 40,000 connectors [1]. Ca-
ble routing is quite a complex task, as for example, the
power cable and electrical signal cable should be physically
separated to avoid electrical interference and can hinder air-
line customization during manufacturing. Also, inaccessi-
ble sensor access point locations and harsh environmental
conditions impose physical restrictions on the use of a wire
harness. This results in the degradation of wiring causing
catastrophic failures. For example, according to a U.S. Navy
report, 6 aircraft were lost due to electrical failure over a 10
year period, about 78 aircrafts are made nonmission capa-
ble due to wiring faults each year and wiring faults cause
more than 1000 mission aborts each year [2]. Replacement
of the current wire harness-based sensors with a wireless
sensor network (WSN) can help to achieve the goal of in-
creasing the number of sensors as well as increasing the
system redundancy. It will also reduce the aircraft system
weight and lead to improved fuel efficiency and reduced
carbon emissions. Replacing the physical cabling by wire-
less connections also offers significant benefits in flexibility,
interoperability, mass reduction and improved robustness.
Use of WSN also enables reduction in direct costs, mainte-
nance cost and obsolescence costs. As most of the current
sensors have double/quadruple redundancy in the form of
sensor hardware and wire harnesses, the use of WSN can re-
sult in huge weight savings. In a recent study, it was shown
that the use of a wireless communication network can re-
sult in 90 lbs. weight reduction of Cessna 310R control sys-
tems, which increases its range by around 10%. Also, in the
same study, assuming only a 50% wire reduction, 267 lbs.
weight saving was shown to be achieved for an SH 60 mili-
tary helicopter control system [3]. Fig. 1 shows the approx-
imate locations of a few typical sensors required for aircraft
flight control systems. As seen in the figure, the sensors are
sparsely located increasing the wire harness length.
Fig. 1 Typical sensor locations of a commercial aircraft [4].
Received 18 October 2010.
c South China University of Technology and Academy of Mathematics and Systems Science, CAS and Springer-Verlag Berlin Heidelberg 2011](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)