Flight test
Encyclopedia
Flight test is a branch of aeronautical engineering that develops and gathers data during flight of an aircraft and then analyzes the data to evaluate the flight characteristics of the aircraft and validate its design, including safety aspects. The flight test phase accomplishes two major tasks: 1) finding and fixing any aircraft design
problems and then 2) verifying and documenting the aircraft capabilities for government certification or customer acceptance. The flight test phase can range from the test of a single new system for an existing aircraft to the complete development and certification of a new aircraft. Therefore the duration of a flight test program can vary from a few weeks to several years.
(TC); in the United Kingdom
(UK), the Civil Aviation Authority; and in the European Union
, the European Aviation Safety Agency
(EASA). Since commercial aircraft development is normally funded by the aircraft manufacturer and/or private investors, the certifying agency does not have a stake in the commercial success of the aircraft. These civil agencies are concerned with the aircraft’s safety and that the pilot’s flight manual accurately reports the aircraft’s performance. The market will determine the aircraft’s suitability to operators. Normally, the civil certification agency does not get involved in flight testing until the manufacturer has found and fixed any development issues and is ready to seek certification.
Flight testing of military aircraft is often conducted at military flight test facilities. The US Navy tests aircraft at Naval Air Station Patuxent River
, MD (a.k.a. “Pax River”) and the US Air Force
at Edwards Air Force Base
, CA. The U.S. Air Force Test Pilot School
and the U.S. Naval Test Pilot School are the programs designed to teach military test personnel. In the UK most military flight testing is conducted by three organizations, the RAF, BAE Systems
and QinetiQ
. For minor upgrades the testing may be conducted by one of these three organisations in isolation, but major programs are normally conducted by a joint trials team (JTT), with all three organisations working together under the umbrella of an Integrated Project Team (IPT) airospace
prepare the test plan, which is essentially certain manoeuvres to be flown (or systems to be exercised). A full certification/qualification flight test program for a new aircraft will require testing for many aircraft systems and in-flight regimes; each is typically documented in a separate test plan. During the actual flight testing, similar maneuvers from all test plans are combined and the data collected on the same flights, where practical. This allows the required data to be acquired in the minimum number of flight hours.
Once the flight test data requirements are established, the aircraft is instrumented to record that data for analysis. Typical instrumentation parameters recorded during a flight test are: temperatures, pressures, structural load
s, vibration/accelerations, noise levels (interior and exterior), aircraft performance parameters (airspeed, altitude, etc.), aircraft controls positions (stick/yoke position, rudder pedal position, throttle position, etc.), engine performance parameters, and atmospheric conditions. During selected phases of flight test, especially during early development of a new aircraft, many parameters are transmitted to the ground during the flight and monitored by the Flight Test Engineer
and test support engineers. This provides for safety monitoring and allows real-time analysis of the data being acquired.
. This ground testing will verify basic aircraft systems operations, measure engine performance, evaluate dynamic systems stability, and provide a first look at structural loads. Flight controls will also be checked out. Once all required ground tests are completed, the aircraft is ready for the first flight. First/maiden flight
is a major milestone in any aircraft development program and is undertaken with the utmost caution.
There are several aspects to a flight test program: handling qualities
, performance, aero-elastic/flutter stability, avionics/systems capabilities, weapons delivery, and structural loads. Handling qualities evaluates the aircraft's controllability and response to pilot inputs throughout the range of flight. Performance testing
evaluates aircraft in relation to its projected abilities, such as speed, range, power available, drag, airflow characteristics, and so forth. Aero-elastic stability evaluates the dynamic response of the aircraft controls and structure to aerodynamic (i.e. air-induced) loads. Structural tests measure the stresses on the airframe, dynamic components, and controls to verify structural integrity in all flight regimes. Avionics/systems testing verifies all electronic systems (navigation, communications, radars, sensors, etc.) perform as designed. Weapons delivery looks at the pilot’s ability to acquire the target using on-board systems and accurately deliver the ordnance
on target. Weapons delivery testing also evaluates the separation of the ordnance as it leaves the aircraft to ensure there are no safety issues. Other military unique tests are: air-to-air refueling
, radar/infrared signature measurement, and aircraft carrier
operations. Emergency situations are evaluated as a normal part of all flight test program. Examples are: engine failure during various phases of flight (takeoff, cruise, landing), systems failures, and controls degradation. The overall operations envelope (allowable gross weights, centers-of-gravity, altitude, max/min airspeeds, maneuvers, etc.) is established and verified during flight testing. Aircraft are always demonstrated to be safe beyond the limits allowed for normal operations in the Flight Manual.
Because the primary goal of a flight test program is to gather accurate engineering data, often on a design that is not fully proven, piloting a flight test aircraft requires a high degree of training and skill, so such programs are typically flown by a specially trained test pilot
, and the data is gathered by a flight test engineer
, and often visually displayed to the test pilot and/or flight test engineer using flight test instrumentation
.
Reporting includes the analyzed data result.
(FTE) or possibly an experimental test pilot
. Other FTEs or pilots could also be involved. Other team members would be the Flight Test Instrumentation Engineer, Instrumentation System Technicians, the aircraft maintenance department (mechanics, electricals, avionics technicians, etc.), Quality/Product Assurance Inspectors, the ground-based computing/data center personnel, plus logistics and administrative support. Engineers from various other disciplines would support the testing of their particular systems and analyze the data acquired for their specialty area.
Since many aircraft development programs are sponsored by government military services, military or government-employed civilian pilots and engineers are often integrated into the flight test team. The government representatives provide program oversight and review and approve data. Government test pilots may also participate in the actual test flights, possibly even on the first/maiden flight
.
Aeronautics
Aeronautics is the science involved with the study, design, and manufacturing of airflight-capable machines, or the techniques of operating aircraft and rocketry within the atmosphere...
problems and then 2) verifying and documenting the aircraft capabilities for government certification or customer acceptance. The flight test phase can range from the test of a single new system for an existing aircraft to the complete development and certification of a new aircraft. Therefore the duration of a flight test program can vary from a few weeks to several years.
Civil Aircraft Flight Test
There are typically two categories of flight test programs – commercial and military. Commercial flight testing is conducted to certify that the aircraft meets all applicable safety and performance requirements of the government certifying agency. In the US, this is the Federal Aviation Administration (FAA); in Canada, Transport CanadaTransport Canada
Transport Canada is the department within the government of Canada which is responsible for developing regulations, policies and services of transportation in Canada. It is part of the Transportation, Infrastructure and Communities portfolio...
(TC); in the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
(UK), the Civil Aviation Authority; and in the European Union
European Union
The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...
, the European Aviation Safety Agency
European Aviation Safety Agency
The European Aviation Safety Agency is an agency of the European Union with offices in Cologne, Germany, which has been given regulatory and executive tasks in the field of civilian aviation safety. It was created on 15 July 2002, and it reached full functionality in 2008, taking over functions...
(EASA). Since commercial aircraft development is normally funded by the aircraft manufacturer and/or private investors, the certifying agency does not have a stake in the commercial success of the aircraft. These civil agencies are concerned with the aircraft’s safety and that the pilot’s flight manual accurately reports the aircraft’s performance. The market will determine the aircraft’s suitability to operators. Normally, the civil certification agency does not get involved in flight testing until the manufacturer has found and fixed any development issues and is ready to seek certification.
Military aircraft Flight Test
Military programs differ from commercial in that the government contracts with the aircraft manufacturer to design and build an aircraft to meet specific mission capabilities. These performance requirements are documented to the manufacturer in the Aircraft Specification and the details of the flight test program (among many other program requirements) are spelled out in the Statement of Work. In this case, the government is the customer and has a direct stake in the aircraft’s ability to perform the mission. Since the government is funding the program, it is more involved in the aircraft design and testing from early-on. Often military test pilots and engineers are integrated as part of the manufacturer’s flight test team, even before first flight. The final phase of the military aircraft flight test is the Operational Test (OT). OT is conducted by a government-only test team with the dictate to certify that the aircraft is suitable and effective to carry out the intended mission.Flight testing of military aircraft is often conducted at military flight test facilities. The US Navy tests aircraft at Naval Air Station Patuxent River
Naval Air Station Patuxent River
"Pax River" redirects here. For the river, see Patuxent River.Naval Air Station Patuxent River , also known as NAS Pax River, is a United States Naval Air Station located in St. Mary's County, Maryland on the Chesapeake Bay near the mouth of the Patuxent River. It is home to the U.S...
, MD (a.k.a. “Pax River”) and the US Air Force
Air force
An air force, also known in some countries as an air army, is in the broadest sense, the national military organization that primarily conducts aerial warfare. More specifically, it is the branch of a nation's armed services that is responsible for aerial warfare as distinct from an army, navy or...
at Edwards Air Force Base
Edwards Air Force Base
Edwards Air Force Base is a United States Air Force base located on the border of Kern County, Los Angeles County, and San Bernardino County, California, in the Antelope Valley. It is southwest of the central business district of North Edwards, California and due east of Rosamond.It is named in...
, CA. The U.S. Air Force Test Pilot School
U.S. Air Force Test Pilot School
The U.S. Air Force Test Pilot School is the Air Force's very advanced flight training school that trains experimental test pilots, flight test engineers, and flight test navigators to carry out tests and evaluations of new aerospace weapon systems and also other aircraft of the U.S. Air Force...
and the U.S. Naval Test Pilot School are the programs designed to teach military test personnel. In the UK most military flight testing is conducted by three organizations, the RAF, BAE Systems
BAE Systems
BAE Systems plc is a British multinational defence, security and aerospace company headquartered in London, United Kingdom, that has global interests, particularly in North America through its subsidiary BAE Systems Inc. BAE is among the world's largest military contractors; in 2009 it was the...
and QinetiQ
QinetiQ
Qinetiq is a British global defence technology company, formed from the greater part of the former UK government agency, Defence Evaluation and Research Agency , when it was split up in June 2001...
. For minor upgrades the testing may be conducted by one of these three organisations in isolation, but major programs are normally conducted by a joint trials team (JTT), with all three organisations working together under the umbrella of an Integrated Project Team (IPT) airospace
Flight Test Processes
Flight Testing is highly expensive and potentially very risky. Unforeseen problems can lead to damage to aircraft and loss of life, both of aircrew and people on the ground. For these reasons modern flight testing is probably one of the most safety conscious professions today. Flight trials can be divided into 3 sections, planning, execution and analysis and reporting.Preparation
For both commercial and military aircraft, flight test preparation begins well before the aircraft is ready to fly. Initially what needs to be tested must be defined, from which the Flight Test EngineersFlight test engineer
A Flight Test Engineer is an engineer involved in the flight testing of prototype aircraft or aircraft systems.-Overview:The Flight Test Engineer generally has overall responsibility for the planning of a specific flight test phase, which includes preparing the test plans in conjunction with other...
prepare the test plan, which is essentially certain manoeuvres to be flown (or systems to be exercised). A full certification/qualification flight test program for a new aircraft will require testing for many aircraft systems and in-flight regimes; each is typically documented in a separate test plan. During the actual flight testing, similar maneuvers from all test plans are combined and the data collected on the same flights, where practical. This allows the required data to be acquired in the minimum number of flight hours.
Once the flight test data requirements are established, the aircraft is instrumented to record that data for analysis. Typical instrumentation parameters recorded during a flight test are: temperatures, pressures, structural load
Structural load
Structural loads or actions are forces, deformations or accelerations applied to a structure or its components.Loads cause stresses, deformations and displacements in structures. Assessment of their effects is carried out by the methods of structural analysis...
s, vibration/accelerations, noise levels (interior and exterior), aircraft performance parameters (airspeed, altitude, etc.), aircraft controls positions (stick/yoke position, rudder pedal position, throttle position, etc.), engine performance parameters, and atmospheric conditions. During selected phases of flight test, especially during early development of a new aircraft, many parameters are transmitted to the ground during the flight and monitored by the Flight Test Engineer
Flight test engineer
A Flight Test Engineer is an engineer involved in the flight testing of prototype aircraft or aircraft systems.-Overview:The Flight Test Engineer generally has overall responsibility for the planning of a specific flight test phase, which includes preparing the test plans in conjunction with other...
and test support engineers. This provides for safety monitoring and allows real-time analysis of the data being acquired.
Execution
When the aircraft is completely assembled and instrumented, it typically conducts many hours of ground testing before its first/maiden flightMaiden flight
The maiden flight of an aircraft is the first occasion on which an aircraft leaves the ground of its own accord. This is similar to a ship's maiden voyage....
. This ground testing will verify basic aircraft systems operations, measure engine performance, evaluate dynamic systems stability, and provide a first look at structural loads. Flight controls will also be checked out. Once all required ground tests are completed, the aircraft is ready for the first flight. First/maiden flight
Maiden flight
The maiden flight of an aircraft is the first occasion on which an aircraft leaves the ground of its own accord. This is similar to a ship's maiden voyage....
is a major milestone in any aircraft development program and is undertaken with the utmost caution.
There are several aspects to a flight test program: handling qualities
Handling qualities
Handling qualities is one of the two principal regimes in the science of flight test . Handling qualities involves the study and evaluation of the stability and control characteristics of an aircraft...
, performance, aero-elastic/flutter stability, avionics/systems capabilities, weapons delivery, and structural loads. Handling qualities evaluates the aircraft's controllability and response to pilot inputs throughout the range of flight. Performance testing
Performance testing
In software engineering, performance testing is in general testing performed to determine how a system performs in terms of responsiveness and stability under a particular workload...
evaluates aircraft in relation to its projected abilities, such as speed, range, power available, drag, airflow characteristics, and so forth. Aero-elastic stability evaluates the dynamic response of the aircraft controls and structure to aerodynamic (i.e. air-induced) loads. Structural tests measure the stresses on the airframe, dynamic components, and controls to verify structural integrity in all flight regimes. Avionics/systems testing verifies all electronic systems (navigation, communications, radars, sensors, etc.) perform as designed. Weapons delivery looks at the pilot’s ability to acquire the target using on-board systems and accurately deliver the ordnance
Aircraft ordnance
Aircraft ordnance or ordnance is weapons used by aircraft. The term is often used when describing the weight of air-to-ground weaponry that can be carried by an aircraft or the weight that has been dropped...
on target. Weapons delivery testing also evaluates the separation of the ordnance as it leaves the aircraft to ensure there are no safety issues. Other military unique tests are: air-to-air refueling
Aerial refueling
Aerial refueling, also called air refueling, in-flight refueling , air-to-air refueling or tanking, is the process of transferring fuel from one aircraft to another during flight....
, radar/infrared signature measurement, and aircraft carrier
Aircraft carrier
An aircraft carrier is a warship designed with a primary mission of deploying and recovering aircraft, acting as a seagoing airbase. Aircraft carriers thus allow a naval force to project air power worldwide without having to depend on local bases for staging aircraft operations...
operations. Emergency situations are evaluated as a normal part of all flight test program. Examples are: engine failure during various phases of flight (takeoff, cruise, landing), systems failures, and controls degradation. The overall operations envelope (allowable gross weights, centers-of-gravity, altitude, max/min airspeeds, maneuvers, etc.) is established and verified during flight testing. Aircraft are always demonstrated to be safe beyond the limits allowed for normal operations in the Flight Manual.
Because the primary goal of a flight test program is to gather accurate engineering data, often on a design that is not fully proven, piloting a flight test aircraft requires a high degree of training and skill, so such programs are typically flown by a specially trained test pilot
Test pilot
A test pilot is an aviator who flies new and modified aircraft in specific maneuvers, known as flight test techniques or FTTs, allowing the results to be measured and the design to be evaluated....
, and the data is gathered by a flight test engineer
Flight test engineer
A Flight Test Engineer is an engineer involved in the flight testing of prototype aircraft or aircraft systems.-Overview:The Flight Test Engineer generally has overall responsibility for the planning of a specific flight test phase, which includes preparing the test plans in conjunction with other...
, and often visually displayed to the test pilot and/or flight test engineer using flight test instrumentation
Flight test instrumentation
Flight test instrumentation is monitoring and recording equipment fitted to aircraft during flight test. It is mainly used on experimental aircraft, prototype aircraft and development aircraft - both military and civil, and can monitor various parameters from the temperatures of specific...
.
Analysis and Reporting
It includes the analysis of a flight for certification.It analyze the internal and outer part of the flight by checking its all minute parts.Reporting includes the analyzed data result.
Flight Test Team
The make-up of the Flight Test Team will vary with the organization and complexity of the flight test program, however, there are some key players who are generally part of all flight test organizations. The leader of a flight test team is usually a flight test engineerFlight test engineer
A Flight Test Engineer is an engineer involved in the flight testing of prototype aircraft or aircraft systems.-Overview:The Flight Test Engineer generally has overall responsibility for the planning of a specific flight test phase, which includes preparing the test plans in conjunction with other...
(FTE) or possibly an experimental test pilot
Test pilot
A test pilot is an aviator who flies new and modified aircraft in specific maneuvers, known as flight test techniques or FTTs, allowing the results to be measured and the design to be evaluated....
. Other FTEs or pilots could also be involved. Other team members would be the Flight Test Instrumentation Engineer, Instrumentation System Technicians, the aircraft maintenance department (mechanics, electricals, avionics technicians, etc.), Quality/Product Assurance Inspectors, the ground-based computing/data center personnel, plus logistics and administrative support. Engineers from various other disciplines would support the testing of their particular systems and analyze the data acquired for their specialty area.
Since many aircraft development programs are sponsored by government military services, military or government-employed civilian pilots and engineers are often integrated into the flight test team. The government representatives provide program oversight and review and approve data. Government test pilots may also participate in the actual test flights, possibly even on the first/maiden flight
Maiden flight
The maiden flight of an aircraft is the first occasion on which an aircraft leaves the ground of its own accord. This is similar to a ship's maiden voyage....
.
External links
- Society of Experimental Test Pilots
- Society of Flight Test Engineers
- Flight Test Safety Committee
- Flight Test Society of Australia
- Airplane Stability and Control
- NASA Introduction to Flight Testing
- Cranfield University Subject Listing for Flight dynamics
- CAFE Foundation flight testing of general aviation aircraft
- a lot of current Flight Test programs (German) Source: FliegerWeb.com
See also
- Maiden flightMaiden flightThe maiden flight of an aircraft is the first occasion on which an aircraft leaves the ground of its own accord. This is similar to a ship's maiden voyage....
- Cooper-Harper rating scaleCooper-Harper rating scaleThe Cooper-Harper rating scale is a set of criteria used by test pilots and flight test engineers to evaluate the handling qualities of aircraft during flight test. The scale ranges from 1 to 10, with 1 indicating the best handling characteristics and 10 the worst. The criteria are evaluative and...
- Aerospace engineeringAerospace engineeringAerospace engineering is the primary branch of engineering concerned with the design, construction and science of aircraft and spacecraft. It is divided into two major and overlapping branches: aeronautical engineering and astronautical engineering...
- Flight test engineerFlight test engineerA Flight Test Engineer is an engineer involved in the flight testing of prototype aircraft or aircraft systems.-Overview:The Flight Test Engineer generally has overall responsibility for the planning of a specific flight test phase, which includes preparing the test plans in conjunction with other...
- Flight test instrumentationFlight test instrumentationFlight test instrumentation is monitoring and recording equipment fitted to aircraft during flight test. It is mainly used on experimental aircraft, prototype aircraft and development aircraft - both military and civil, and can monitor various parameters from the temperatures of specific...
- Variable-Response Research Aircraft