Compliance with applicable specifications or operational requirements requires accurate TSPI. The tester must identify the system accuracies needed to achieve compliance and then choose the correct TSPI source. Part of identifying TSPI sources includes determining the cost to the program. As a general rule, more accuracy will require more money. The truth systems must be at least four times as accurate as the system under test. With today's technology, this task is becoming more difficult, as many systems provide accuracies better than most truth systems can measure. In these cases, the tester, in concert with range and instrumentation personnel, must develop sensor fusion algorithms to assist them.

The flight testing of communications systems is avionics flight testing in its most basic form, but it does illustrate many of the common factors seen in the more complex systems. The testing of communication systems occurs more often than one would expect. Radios are often upgraded, which requires a flight test program, but these upgrades may be many years apart. What occurs on a more frequent basis is the relocation of antennas or the installation of stores or other obstructions that may affect communications. Some flight testing may be required to ensure that no degradation of communications due to these modifications has occurred. Radios, because they transmit as well as receive radio frequency (RF) energy, are also key players in electromagnetic interference/electromagnetic compatibility (EMI/EMC) testing.

The Part 23/25/27/29 in the title of this section refers to the U.S. Federal Aviation Administration (FAA) and European Aviation Safety Administration (EASA) (formerly Joint Aviation Administration) definitions of aircraft types. Part 23 aircraft are defined as normal, utility, acrobatic, and commuter category airplanes; Part 25 defines transport category airplanes. The discussions in this section are applicable to Part 27 (utility helicopters) and Part 29 (transport helicopters) as well as military installations. The systems in this section have, for the most part, been developed for the general and commercial aviation market or mandated for use by the state authorities. Since the emphasis will be on compliance with the applicable certification requirements, some time will be spent on the civil certification process, its history, and a review of the types of documents that you will need to reference. The discussion will continue with hardware, software, and safety considerations and the requirements for each. Controls and displays and human factors, which are considerations for all test plans, will be discussed in detail and documents to assist in the test planning process will be identified. The systems that will be covered include weather RADAR, global satellite based navigation civil certifications, reduced vertical separation minima (RVSM), terrain awareness warning systems (TAWS), traffic alert and collision avoidance systems (TCAS), flight management systems (FMS), landing systems, autopilots, and integrated navigation systems. Suggested reading and reference material are numerous and will be called out in each of the sections.

Radar evaluation is perhaps one of the most exhaustive, complex, and challenging types of testing that the flight test engineer will encounter. As with all other avionics and weapons systems, it is imperative that the evaluator possess a basic knowledge of radar and an in-depth knowledge of the system under test. For the tester who is new to radar, I recommend that you start with Stimson's Introduction to Airborne Radar, 3rd Edition (Raleigh, NC: SciTech Publishing, 2014). This is a wonderful book, an easy read, and a must reference for the radar engineer. A companion text is Merrill I. Skolnik's Introduction to Radar Systems, 3rd edition (New York: McGraw-Hill, 2002). This book is more of the textbook that you have seen in your college or university, but it gives an excellent treatment of clutter and detections at sea. Another reference is one given in previous chapters: the NATO Aerospace Group for Avionics Research and Development (AGARD), now called the NATO Research and Technology Organization. They have two excellent guides: RTO-AG-300, volume 16, Introduction to Airborne Early Warning Radar Flight Test, and basic radar flight testing information is contained in AGARD's Introduction to Avionics Flight Test. Attendance in a radar and radar flight test course is also highly recommended. The purpose of this section is not to repeat what is contained in the aforementioned references. Radar theory is covered only to make the test procedures understandable. The section will review radar fundamentals, identify radar modes of operation, examine the methods of test for these modes, and address any special test considerations.

In this chapter we will discuss the system aspects of weapons integration. The chapter is not concerned with loads, flutter, captive carry, or station clearance issues, although they will be touched upon during the discussions. As usual, some references are available to the evaluator, and these will be quoted where necessary. The first reference is the MIL-STD-1760D, “Interface Standard for Aircraft-Store Electrical Interconnection System,”August 1, 2003. This document covers the digital data bus requirements for aircraft and stores, and was covered at some length in chapter 3 of this text. The second is MIL-HDBK-1763, “Aircraft/Stores Compatibility: Systems Engineering Data Requirements and Test Procedures,”June 15, 1988. A detailed examination of the requirements in 1763 is covered in section 10.5. A third reference is from the NATO Aerospace Group for Avionics Research and Development (AGARD), now called the NATO Research and Technology Organization. AGARD Flight Test Techniques Series, Volume 10, “Weapon Delivery Analysis and Ballistic Flight Testing,”July 1992, is perhaps one of the better documents available to evaluators for the test and evaluation of weapons systems. The highlights of this AGARD document are explained in section 10.6. A general document used for all aircraft is Mil-A-8860B, “General Specifications for Airplane Strength and Rigidity,”May 20, 1987.

It is envisioned by the FAA that by 2016 UAVs will be flying in the NAS in fairly large numbers. There will be an increased need for T&E personnel to validate the designs and performance of these systems. The test and evaluation of UAV aircraft will encompass all of the testing previously covered for manned aircraft, but presents some unique problems not seen with manned aircraft. Safety will play a major role in all UAV testing, even more so than with the development of manned aircraft; potential hazards cannot be easily mitigated by aircrew action. Human factors and workload must be evaluated with respect to the envisioned mission, which may require long missions at remote sites. Communications are critical and the evaluation team must be cognizant of potential latencies, lost link, data rates, and volume. Changes to S/W must be approached even more carefully than with manned aircraft as there is really no second chance.

In DT&E, the evaluators are tasked to determine if the system meets the requirements of the specification, the stated capability or the terms of the contract. In fact, the majority of the time spent in DT&E is to get the system to perform its intended function. DT&E progresses from the development to demonstration phases of test until enough data are collected to statistically prove that the requirements have been met. OT&E ensures that the system is effective and suitable in real-world scenarios under operational conditions. The test methodology is different, and more importantly the evaluators need to know how the system will be utilized operationally as opposed to operations in a sanitized test world.