Flight testing is the process of testing a new aircraft or various parts of an aircraft through a number of different methods to ensure they are safe, effective, and reliable for use in flight. This is typically performed in a number of different ways before an airplane ever leaves the ground, and can include lab testing and ground testing. It can involve numerous test engineers and one or more test pilots who will ultimately test the aircraft or new devices in the air. Flight testing typically culminates with this type of test flight, often referred to as the maiden flight, and this final process can be quite dangerous.
There are usually two different types of flight testing a new aircraft or device will have to undergo before acceptance for general use: commercial testing or military testing. Commercial testing is usually reserved for new types of aircraft or parts of an aircraft intended for use in commercial flights such as those that carry passengers or private cargo through airspace. This type of testing is often performed initially by test engineers and pilots working for the company that is developing the new craft or systems for commercial use. Commercial flight testing will then typically be completed by a government agency that acts on behalf of the country in which the hardware will be used.
Military flight testing, on the other hand, will usually involve governmental or military test engineers and pilots during the development of the new aircraft or system. Since the government is the customer for this type of development, there is usually a more distinct government and military presence during testing. While commercial development and testing often revolves primarily around the safety and reliability of what is being tested, military testing also often includes the effectiveness of the aircraft or system in relation to military endeavors. Military flight testing for a new type of spy plane, for example, would also test how well the craft eludes radar detection and perhaps how well its systems can capture images from high altitudes.
Regardless of what type of flight testing is being performed, the testing will usually involve three distinct steps. The first part of testing often involves lab or theoretical testing, which tests the new systems in a lab environment or uses computer simulations to evaluate aircraft performance. This is typically followed by ground testing, in which the various systems are evaluated and tested while the aircraft remains on the ground. The final step in flight testing involves the maiden flight of the aircraft and tests how the systems perform in the air. This can be incredibly dangerous, and most flight test pilots are extremely skilled pilots with extensive training regarding experimental aircraft.