Flight test is a branch of
aeronautical engineeringthat develops and gathers data during flight of an aircraft and then analyses 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.
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 Canada(TC); in the United Kingdom (UK), the Civil Aviation Authority; and in the European Union, the Joint Aviation Authorities(JAA). 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, MD (a.k.a. “Pax River”) and the US Air Forceat Edwards Air Force Base, CA. The U.S. Air Force Test Pilot Schooland the U.S. Naval Test Pilot Schoolare the programs designed to teach military test personnel. In the UK most military flight testing is conducted by three organisations, the RAF, BAE Systemsand 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)
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.
For both commercial and military aircraft, flight test preparation begins well before the aircraft is ready to fly. Initially requirements for flight testing must be defined, from which the Flight Test Engineers prepare the test plan(s). These will include the aircraft configuration, data requirements and 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 loads, 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.
When the aircraft is completely assembled and instrumented, it typically conducts many hours of ground testing before its first/
maiden flight. 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 controlswill also be checked out. Once all required ground tests are completed, the aircraft is ready for the first flight. First/ maiden flightis 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 testingevaluates 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 carrieroperations. 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 a test pilot and/or flight test engineer using flight test instrumentation.
Analysis and Reporting
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 engineer(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, electricials, 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/
* [http://www.setp.org/ Society of Experimental Test Pilots]
* [http://www.sfte.org/ Society of Flight Test Engineers]
* [http://www.flighttestsafety.org/ Flight Test Safety Committee]
* [http://www.ftsa.org.au/ Flight Test Society of Australia]
* [http://assets.cambridge.org/052180/9924/sample/0521809924ws.pdf "Airplane Stability and Control"]
* [http://www.dfrc.nasa.gov/Education/OnlineEd/Intro2Flight/index.html NASA Introduction to Flight Testing]
* [http://aerade.cranfield.ac.uk/subject-listing/flight.html Cranfield University Subject Listing for Flight dynamics]
Cooper-Harper rating scale
Flight test engineer
Flight test instrumentation
Variable-Response Research Aircraft
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flight test — noun A trial flight of an aircraft • • • Main Entry: ↑flight * * * flight test «FLYT TEHST», transitive verb. to test in or by actual flight. flight test, a test in or by actual flight. * * * 1. n. a flight of an aircraft, rocket, or equipment to … Useful english dictionary
flight-test — [flīt′test΄] vt. to put (an aircraft, rocket, etc.) through an actual test (flight test) of flight performance … English World dictionary
flight-test — flight′ test v. t. aer. to test (an aircraft or spacecraft) in flight • Etymology: 1930–35 … From formal English to slang
flight-test — flight ,test verb transitive to test a new airplane by flying it in order to make certain that it is safe … Usage of the words and phrases in modern English
flight-test — ˈ ̷ ̷ˌ ̷ ̷ transitive verb : to test (an airplane) in flight * * * /fluyt test /, v.t. to test (an airplane or the like) in flight. [1930 35] * * * flightˈ test transitive verb • • • Main Entry: ↑flight * * * flight test UK US verb [tra … Useful english dictionary
flight-test — UK / US verb [transitive] Word forms flight test : present tense I/you/we/they flight test he/she/it flight tests present participle flight testing past tense flight tested past participle flight tested to test a new plane by flying it in order… … English dictionary
flight test — orlaivio skrydžio bandymai statusas T sritis Gynyba apibrėžtis Orlaivių, raketų ir kitų skraidomųjų priemonių skrydžio (skriejimo) ir leidimo bandymai. Jie planuojami konkretiems bandymo tikslams pasiekti ir informacijai apie operaciją gauti.… … NATO terminų aiškinamasis žodynas
flight test — raketos skriejimo bandymai statusas T sritis Gynyba apibrėžtis Orlaivių, raketų ir kitų skraidomųjų priemonių skrydžio (skriejimo) ir leidimo bandymai. Jie planuojami konkretiems bandymo tikslams pasiekti ir informacijai apie operaciją gauti.… … NATO terminų aiškinamasis žodynas
flight test — Test of an aircraft, rocket, missile, or other vehicle by actual flight or launching. Flight tests are planned to achieve specific test objectives and gain operational information … Military dictionary
flight test — i. An actual test in the air to ascertain the serviceability of an aircraft after a major component change or repair, to ascertain flight characteristics, or to achieve other specified objectives. ii. A test of a component of a flying vehicle, or … Aviation dictionary