It gives me an immense pleasure to present the report of the Project undertaken by me
during summer training. I owe special debt of gratitude to Mr. S. P. Singh, Sr. Manager
(Training) at Hindustan Aeronautics Limited, Lucknow for his constant support and
guidance throughout the course of my work. His sincerity, thoroughness and perseverance
have been a constant source of inspiration for me. It is only his cognizant efforts that my
endeavours have seen light of the day.
I also take the opportunity to acknowledge the contribution of all the staff members at
HAL for their full support and assistance during the development of the project.
I am also very thankful to my HOD and faculty members Er. M.L. Guar Sir & Er. Dilip
Rathor Sir who have suggested me to do the training from HAL.
This project is a study of some of the major electronic control systems that are used in
various aircrafts today. The main topics of concern in this project are:
2. Electronic flight instrumentation system
3. Full Authority Digital Electronics Control (FADEC)
4. Limited Authority Spark Advance Regulator
The control systems are used to keep a tab on the working of various parts in the aircraft
depending on either their software or implementations. Engine operating parameters such as
fuel flow, stator vane position, bleed valve position, and others are computed from this data
and applied as appropriate. Engineering processes must be used to design, manufacture,
install and maintain the sensors which measure and report flight and engine parameters to
the control system itself. They have varied usage in different instruments, mechanical
systems and electrical systems as well.
ABOUT HINDUSTAN AERONAUTICS LIMITED
Hindustan Aeronautics Limited (HAL) came into existence on 1st October 1964. The
Company was formed by the merger of Hindustan Aircraft Limited with Aeronautics India
Limited and Aircraft Manufacturing Depot, Kanpur. The Company traces its roots to the
pioneering efforts of an industrialist with extraordinary vision, the late Seth Walchand
Hirachand, who set up Hindustan Aircraft Limited at Bangalore in association with the
erstwhile princely State of Mysore in December 1940. The Government of India became a
shareholder in March 1941 and took over the Management in 1942. Today, HAL has 19
Production Units and 10 Research & Design Centres in 8 locations in India. The Company
has an impressive product track record - 15 types of Aircraft/Helicopters manufactured with
in-house R & D and 14 types produced under license. HAL has manufactured over 3658
Aircraft/Helicopters, 4178 Engines, Upgraded 272 Aircraft and overhauled over 9643
Aircraft and 29775 Engines. HAL has been successful in numerous R & D programs
developed for both Defence and Civil Aviation sectors.
HAL has made substantial progress in its current projects:
• Advanced Light Helicopter – Weapon System Integration (ALH-WSI)
• Tejas - Light Combat Aircraft (LCA)
• Intermediate Jet Trainer (IJT)
• Light Combat Helicopter (LCH)
• Various military and civil upgrades.
Dhruv was delivered to the Indian Army, Navy, Air Force and the Coast Guard in March
2002, in the very first year of its production, a unique achievement.
HAL has played a significant role for India's space programs by participating in the
manufacture of structures for Satellite Launch Vehicles like
• PSLV (Polar Satellite Launch Vehicle)
• GSLV (Geo-synchronous Satellite Launch Vehicle)
• IRS (Indian Remote Satellite)
• INSAT (Indian National Satellite)
Apart from these, other major diversification projects are manufacture & overhaul of
Industrial Marine Gas Turbine and manufacture of Composites.
HAL has formed the following Joint Ventures (JVs):
• BAeHAL Software Limited
• Indo-Russian Aviation Limited (IRAL)
• Snecma-HAL Aerospace Pvt Ltd
• SAMTEL-HAL Display System Limited
• HALBIT Avionics Pvt Ltd
• HAL-Edgewood Technologies Pvt Ltd
• INFOTECH-HAL Ltd
• TATA-HAL Technologies Ltd
• HATSOFF Helicopter Training Pvt Ltd
• International Aerospace Manufacturing Pvt Ltd
• Multi Role Transport Aircraft Ltd
Several Co-production and Joint Ventures with international participation are under
consideration. HAL's supplies / services are mainly to Indian Defence Services, Coast
Guard and Border Security Force. Transport Aircraft and Helicopters have also been
supplied to Airlines as well as State Governments of India. The Company has also achieved
a foothold in export in more than 30 countries, having demonstrated its quality and price
competitiveness. HAL was conferred NAVRATNA status by the Government of India on
22nd June 2007. The Company scaled new heights in the Financial Year 2010-11 with
Turnover of Rs.13, 116 Crores and PBT of Rs 2,841 Crores.
The Su-30 two-seat fighter-bomber is intended to defeat aerial, ground, sea and surface
targets, including small and moving ones, while conducting autonomous and group combat
actions by day and night, in any weather and in conditions of enemy's jamming, fire and
information opposition, as well as to conduct aerial reconnaissance. The Su-30 multirole
aircraft combines the properties of an air superiority fighter, an air-defence suppression
aircraft, and a strike aircraft. It can equally defeat diverse aerial, ground, and sea targets. All
stages of its flight, including low-altitude nap-of-earth flying, as well as solo and group
combat employment against aerial and ground targets are automated. The Su-30 weapons
complement enables its crew to deliver a preventive attack against any aerial targets,
including stealth ones, effectively fight against air superiority fighters, electronic warfare
and airborne early warning aircraft, and flying command posts, neutralize air-defence
weapon control systems when performing en-route flight to a target, and deliver standoff
attacks against ground and surface targets. The Su-30 is developed from the Su-27 air
superiority fighter with due account for the combat use of the Su-24 front-line bomber and
its modifications, the Su-25 close-support aircraft and its modified versions, as well as
advanced weapons and the most up-to-date technologies. For the first time in the world
practice for aircraft of this class, the cockpit is made as an armored all-welded titanium
capsule. It can be refuelled from the 11-78 (П-78М) flying tanker or other aircraft equipped
with unified fuel dispensing units.
The powerful multimode enhanced-definition phased-array radar enables it to detect small-
size ground targets and simultaneously track while scan several aerial targets. The radar
features a ground-mapping mode and ensures nap-of-earth flying. The weapon control
system ensures automatic missile launch with preset intervals and in assigned sequence. The
Su-30 is equipped with a navigation complex incorporating a laser gyro-based inertial
navigation system combined with a satellite navigation system receiver, and radio
navigation facilities. The automatic flight control system makes it possible to perform a
planned-route flight and return to a preprogrammed airfield in the manual, automatic or
director flight modes, including a prelanding maneuver, landing approach down to an
altitude of 50 m and repeated approach for landing. The aircraft is equipped with a powerful
automated ECM system with provision for its further upgrading. The multifunctional control
consoles are a core of the avionics control system intended to detect launch of missiles by an
attacker by referring to their thermal radiation, and a chaff/hot decoy dispenser intended to
set up passive jamming. Its high flight performance, advanced avionics, powerful ECM
system, and diverse weapon options make the Su-30 the world's most powerful new-
generation fighter-bomber. Owing to multihour flights with air refueling, the Su-30 is
capable of loitering over wide areas and executing deterrence missions, quickly ferrying to
areas, which pose a threat. Engineering solutions invested in the design configuration of the
Su-30 open up wide potentialities for developing the entire family of advanced
modifications of this aircraft at customer's request.
ELECTRONIC FLIGHT INSTRUMENT SYSTEM
An electronic flight instrument system (EFIS) is a flight deck instrument display system in
which the display technology used is electronic rather than electromechanical. EFIS
normally consists of a primary flight display (PFD), multi-function display (MFD) and
engine indicating and crew alerting system (EICAS) display. Although cathode ray
tube (CRT) displays were used at first, liquid crystal displays (LCD) are now more
The complex electromechanical attitude director indicator (ADI) and horizontal situation
indicator (HSI) were the first candidates for replacement by EFIS. However, there are now
few flight deck instruments for which no electronic display is available.
EFIS installations vary greatly. A light aircraft might be equipped with one display unit, on
which are displayed flight and navigation data. A wide-body aircraft is likely to have six or
more display units. Typical EFIS displays and controls can be seen at this B737 technical
information web site. An EFIS installation will have the following components:
PRIMARY FLIGHT DISPLAY:
On the flight deck, the display units are the most obvious parts of an EFIS system, and
are the features which give rise to the name "glass cockpit". The display unit taking the
place of the ADI is called the primary flight display (PFD). If a separate display replaces
the HSI, it is called the navigation display. The PFD displays all information critical to
flight, including calibrated airspeed, altitude, heading, attitude, vertical speed and yaw.
The PFD is designed to improve a pilot's situational awareness by integrating this
information into a single display instead of six different analog instruments, reducing the
amount of time necessary to monitor the instruments. PFDs also increase situational
awareness by alerting the aircrew to unusual or potentially hazardous conditions — for
example, low airspeed and high rate of descent— by changing the color or shape of the
display or by providing audio alerts.
1. The names Electronic Attitude Director Indicator and Electronic Horizontal
Situation Indicator are used by some manufacturers. However, a simulated ADI is
only the centerpiece of the PFD. Additional information is both superimposed on
and arranged around this graphic.
2. Multi-function displays can render a separate navigation display unnecessary.
Another option is to use one large screen to show both the PFD and navigation
3. The PFD and navigation display (and multi-function display, where fitted) are often
physically identical. The information displayed is determined by the system
interfaces where the display units are fitted. Thus, spares holding is simplified: the
one display unit can be fitted in any position.
4. LCD units generate less heat than CRTs; an advantage in a congested instrument
panel. They are also lighter, and occupy a lower volume.
Multi-function display (MFD) / navigation display (ND):
The MFD (multi-function display) displays navigational and weather information from
multiple systems. MFDs are most frequently designed as "chart-centric", where the
aircrew can overlay different information over a map or chart. Examples of MFD
overlay information include the aircraft's current route plan, weather information from
either on-board radar or lightning detection sensors or ground-based sensors, e.g.,
NEXRAD, restricted airspace and aircraft traffic. The MFD can also be used to view
other non-overlay type of data (e.g., current route plan) and calculated overlay-type
data, e.g., the glide radius of the aircraft, given current location over terrain, winds, and
aircraft speed and altitude.
MFDs can also display information about aircraft systems, such as fuel and electrical
systems (see EICAS, below). As with the PFD, the MFD can change the color or shape
of the data to alert the aircrew to hazardous situations.
Engine indications and crew alerting system (EICAS) / electronic
centralized aircraft monitoring (ECAM):
EICAS (Engine Indications and Crew Alerting System) displays information about the
aircraft's systems, including its fuel, electrical and propulsion systems (engines). EICAS
displays are often designed to mimic traditional round gauges while also supplying
digital readouts of the parameters. EICAS improves situational awareness by allowing
the aircrew to view complex information in a graphical format and also by alerting the
crew to unusual or hazardous situations. For example, if an engine begins to lose oil
pressure, the EICAS might sound an alert, switch the display to the page with the oil
system information and outline the low oil pressure data with a red box. Unlike
traditional round gauges, many levels of warnings and alarms can be set. Proper care
must be taken when designing EICAS to ensure that the aircrew are always provided
with the most important information and not overloaded with warnings or alarms.
ECAM is a similar system used by Airbus, which in addition to providing EICAS
functions also recommend remedial action.
The pilots are provided with controls, with which they select display range and mode
(for example, map or compass rose) and enter data (such as selected heading).
Where inputs by the pilot are used by other equipment, data buses broadcast the pilot's
selections so that the pilot only needs to enter the selection once. For example, the pilot
selects the desired level-off altitude on a control unit. The EFIS repeats this selected
altitude on the PFD and by comparing it with the actual altitude (from the air data
computer) generates an altitude error display. This same altitude selection is used by the
automatic flight control system to level off, and by the altitude alerting system to
provide appropriate warnings.
The EFIS visual display is produced by the symbol generator. This receives data inputs
from the pilot, signals from sensors, and EFIS format selections made by the pilot. The
symbol generator can go by other names, such as display processing computer, display
electronics unit, etc.
The symbol generator does more than generate symbols. It has (at the least) monitoring
facilities, a graphics generator and a display driver. Inputs from sensors and controls
arrive via data buses, and are checked for validity. The required computations are
performed, and the graphics generator and display driver produce the inputs to the
Like personal computers, flight instrument systems need power-on-self-test facilities
and continuous self-monitoring. Flight instrument systems, however, need additional
Input validation — verify that each sensor is providing valid data
Data comparison — cross check inputs from duplicated sensors
Display monitoring — detect failures within the instrument system
With EFIS, the comparator function is as simple as ever. Is the roll data (bank angle) from
sensor 1 the same as the roll data from sensor 2? If not, put a warning caption (such as
CHECK ROLL) on both PFDs. Comparison monitors will give warnings for airspeeds,
pitch, roll and altitude indications. The more advanced EFIS systems, more comparator
monitors will be enabled.
An EFIS display allows no easy re-transmission of what is shown on the display. What is
required is a new approach to display monitoring that provides safety equivalent to that of
the traditional system. One solution is to keep the display unit as simple as possible, so that
it is unable to introduce errors. The display unit either works or does not work. A failure is
always obvious, never insidious. Now the monitoring function can be shifted upstream to
the output of the symbol generator.
In this technique, each symbol generator contains two display monitoring channels. One
channel, the internal, samples the output from its own symbol generator to the display unit
and computes, for example, what roll attitude should produce that indication. This computed
roll attitude is then compared with the roll attitude input to the symbol generator from
the INS or AHRS. Any difference has probably been introduced by faulty processing, and
triggers a warning on the relevant display.
The external monitoring channel carries out the same check on the symbol generator on the
other side of the flight deck: the Captain's symbol generator checks the First Officer's, the
First Officer's checks the Captain's. Whichever symbol generator detects a fault puts up a
warning on its own display.
The external monitoring channel also checks sensor inputs (to the symbol generator) for
reasonableness. A spurious input, such as a radio height greater than the radio altimeter's
maximum, results in a warning.
Full Authority Digital Electronics Control (FADEC)
Full Authority Digital Engine (or Electronics) Control (FADEC) is a system consisting
of a digital computer, called an electronic engine controller (EEC) or engine control
unit(ECU), and its related accessories that control all aspects of aircraft engine performance.
FADECs have been produced for both piston engines and jet engines.
True full authority digital engine controls have no form of manual override available,
placing full authority over the operating parameters of the engine in the hands of the
computer. If a total FADEC failure occurs, the engine fails. If the engine is controlled
digitally and electronically but allows for manual override, it is considered solely an EEC
or ECU. An EEC, though a component of a FADEC, is not by itself FADEC. When
standing alone, the EEC makes all of the decisions until the pilot wishes to intervene.
FADEC works by receiving multiple input variables of the current flight condition
including air density, throttle lever position, engine temperatures, engine pressures, and
many other parameters. The inputs are received by the EEC and analyzed up to 70 times per
second. Engine operating parameters such as fuel flow, stator vane position, bleed valve
position, and others are computed from this data and applied as appropriate. FADEC also
controls engine starting and restarting. The FADEC's basic purpose is to provide optimum
engine efficiency for a given flight condition.
FADEC not only provides for efficient engine operation, it also allows the manufacturer to
program engine limitations and receive engine health and maintenance reports. For example,
to avoid exceeding a certain engine temperature, the FADEC can be programmed to
automatically take the necessary measures without pilot intervention.
With the operation of the engines so heavily relying on automation, safety is a great
concern. Redundancy is provided in the form of two or more, separate identical digital
channels. Each channel may provide all engine functions without restriction. FADEC also
monitors a variety of analog, digital and discrete data coming from the engine subsystems
and related aircraft systems, providing for fault tolerant engine control.
A typical civilian transport aircraft flight may illustrate the function of a FADEC. The flight
crew first enters flight data such as wind conditions, runway length, or cruise altitude, into
the flight management system (FMS). The FMS uses this data to calculate power settings
for different phases of the flight. At takeoff, the flight crew advances the throttle to a
predetermined setting, or opts for an auto-throttle takeoff if available. The FADECs now
apply the calculated takeoff thrust setting by sending an electronic signal to the engines;
there is no direct linkage to open fuel flow. This procedure can be repeated for any other
phase of flight. In flight, small changes in operation are constantly made to maintain
efficiency. Maximum thrust is available for emergency situations if the throttle is advanced
to full, but limitations can’t be exceeded; the flight crew has no means of manually
overriding the FADEC.
Better fuel efficiency
Automatic engine protection against out-of-tolerance operations
Safer as the multiple channel FADEC computer provides redundancy in case of
Care-free engine handling, with guaranteed thrust settings
Ability to use single engine type for wide thrust requirements by just reprogramming
Provides semi-automatic engine starting
Better systems integration with engine and aircraft systems
Can provide engine long-term health monitoring and diagnostics
Number of external and internal parameters used in the control processes increases
by one order of magnitude
Reduces the number of parameters to be monitored by flight crews
Due to the high number of parameters monitored, the FADEC makes possible "Fault
Tolerant Systems" (where a system can operate within required reliability and safety
limitation with certain fault configurations)
Can support automatic aircraft and engine emergency responses (e.g. in case of
aircraft stall, engines increase thrust automatically).
Full authority digital engine controls have no form of manual override available,
placing full authority over the operating parameters of the engine in the hands of the
computer. If a total FADEC failure occurs, the engine fails. In the event of a total
FADEC failure, pilots have no way of manually controlling the engines for a restart, or
to otherwise control the engine. As with any single point of failure, the risk can be
mitigated with redundant FADECs.
High system complexity compared to hydro-mechanical, analogue or manual control
High system development and validation effort due to the complexity.
Engineering processes must be used to design, manufacture, install and maintain the
sensors which measure and report flight and engine parameters to the control system
Software engineering processes must be used in the design, implementation and
testing of the software used in these safety-critical control systems. This requirement led
to the development and use of specialized software such as SCADA.
Limited Authority Spark Advance Regulator
LASAR, which stands for Limited Authority Spark Advance Regulator, is the first
microprocessor based engine control system approved by the FAA for general aviation
piston aircraft. With the system operating in its automatic mode, cylinder head temperature,
manifold pressure, and engine speed (RPM) are monitored by the LASAR controller to
establish and command the optimum ignition timing and spark energy to produce maximum
torque from the engine. LASAR has an inherent mechanical magneto backup system that
automatically assumes control if electrical power is interrupted or if the microprocessor
detects a system fault. STC approval has been granted for most 320, 360 and 540 engines.
Installation requires replacement of standard magnetos with LASAR magnetos, a LASAR
Control Box, which is mounted to the firewall, a low-voltage control harness that carries the
electronic signals between the system components. Specify exact aircraft and Engine
Models for quotation or LASAR systems.
The FADEC, LASAR & ELECTRONIC FLIGHT INSTRUMENT SYSTEM are the basic
and very important electronics based control systems used in various aircrafts. Some of their
components restrict their use to experimental aircraft and certain other aircraft categories
depending on local regulations. Uncertified systems are found in Sport Pilot category
aircraft, including factory built, microlight and ultralight aircraft. These systems can be
fitted to certified aircraft in some cases as secondary or backup systems depending on local
aviation authorities’ rules and regulations. The flexibility afforded by software
modifications, minimises costs when new aircraft equipment and new regulations are
Thus, these systems have varied and huge use in today’s aircrafts.