The history of tactical UAV programmes is littered with failures, but loaded with lessons

Peter La Franchi/CANBERRA

What most failed unmanned air vehicles (UAV) programmes have in common are poorly defined operational requirements, technical over-ambition, specification creep and lack of consideration of user needs. Even where programmes have pursued a low-risk strategy and sought to minimise development requirements, past lessons show that other pitfalls stand in the way of success.

What failed in the past may have done so because technology was not ready. This is particularly true of tactical UAVs (TUAVs). But the concepts of the past are regularly revisited, and are slowly becoming possible. So what constituted a bad programme in the past may not be a bad programme in the future. The evolution of TUAVs testifies to this.

Nowhere have the lessons of the past been more costly than in the USA, where the legacy of eight programmes started during the 1980s and 1990s is only two systems that have been accepted operationally at a cumulative cost of billions of dollars.

The costliest failure of all was the Lockheed Aquila programme, which was intended to provide the US Army with a short-range TUAV to provide real-time information on enemy activity beyond the line of sight of ground commanders. The system was to be operated in the field by four soldiers.

The programme was launched in 1979 with initial projections suggesting development would take 43 months and cost $123 million. This was to be followed by the purchase of 780 air vehicles and support equipment for an estimated $440 million. The final programme cost when Aquila was cancelled in 1987 amounted to more than $1 billion for development, with acquisition costs projected at $1.1 billion for 376 air vehicles.

Specification creep took hold of the project almost from the outset, particularly in avionics and sensor payload requirements, pushing the air vehicle to its design limits early in development. According to an assessment by the US General Accounting Office (GAO): "Aquila was expected to fly by autopilot, carry sensors to locate and identify enemy point targets day or night, use a laser to designate the targets for the Copperhead artillery projectile, provide conventional artillery adjustment and survive Soviet air defences.

"Achieving the latter expectation required development of a jam-resistant, secure communications link but using the secure link degraded the video quality, which interfered with the ability to do targeting." The net result, the GAO testified to US Congress in April 1997, was that "during operational testing in 1987, Aquila was only able to successfully meet mission requirements on seven of 105 flights".

In contrast to the approach taken with Aquila, the US Navy programme to acquire the Pioneer TUAV was initiated in late 1985 as an "off-the-shelf" acquisition from Israel Aircraft Industries (IAI) and US firm, AAI.

The USN first used Pioneer operationally in the 1991 Gulf War to provide surveillance and targeting for naval gunfire, carry out battle damage assessment and to support maritime interception missions. The US Department of Defense (DoD) April 1992 report to Congress on the conduct of the Gulf War lauds the capability, noting: "[The] navy's Pioneer UAV system's availability exceeded expectations [and] provided the first successful integration of ship-based UAVs into combat operations." The only downside noted was that "shipboard launch and recovery systems were cumbersome and required increased logistic support".

Despite this, four months before commencement of the "hot" war of January 1991, while Pioneer UAVs were carrying out maritime surveillance missions in the Persian Gulf area, the GAO released a highly critical assessment of the system.

While it was meant to be an off-the-shelf purchase, the September 1990 report said the USN had proceeded to acquisition without carrying out a test and acceptance programme beforehand. Emergent problems, the report found, resulted in the $56 million acquisition price for nine systems increasing by $50 million to pay for system redesign and modification.

How not to buy a UAV

Another GAO assessment, in September 1995, identified the Pioneer as an example of how not to acquire a TUAV system, this time in the context of the Hunter programme, which was to replace the "interim" Pioneer UAV in USN service. Pioneer's performance in the Gulf War, the GAO reported, "was not without problems. Pioneer's lack of reliability resulted in excessive maintenance and support requirements. Further, electromagnetic interference from other systems caused crashes in some cases and sometimes prevented video imagery from being transmitted to the ground control station so that it could be used."

The acquisition method used for Pioneer, the 1995 report said, involved testing for operational applicability after system purchase: "When the testing revealed problems, the navy employed a costly trial-and-error effort trying to overcome the problems. The necessary changes included a modified engine, new foam-filled wings so that crashed vehicles could float until salvaged, a new landing recovery system, new flight control software and a new propeller."

DoD records reveal that, in the four years following initial procurement, the USN spent $28 million in research and development funds, and an additional $22 million in procurement funds for replacement hardware trying to get Pioneer's performance up to the minimum essential level," the GAO said.

The bottom line, according to the report, was that the Pioneer programme showed that "premature entry into production resulted in extensive and costly systems redesigns in attempting to achieve acceptable system performance." The Hunter Joint TUAV programme, the report warned prophetically, was on the verge of repeating the same mistakes.

The Hunter had its origins both in the demise of the Aquila and moves by Congress in 1987 to consolidate all funding for DoD UAV programmes into a single area to avoid duplication and maximise commonality. This resulted in creation of the US Joint UAV Projects Office in 1988, with the Hunter as its lead project.

The concept was for a 200km- (110nm) range system to be operated by the USN as a replacement for Pioneer, by the US Marine Corps and by the US Army. The programme was kicked off in 1988 with plans for the purchase of 50 systems comprising a total of 400 air vehicles. The proposed payload consisted of a daylight television, infrared sensor and a data relay terminal to allow beyond line-of-sight transmission of imagery using a second air vehicle. Initial cost projections totalled $1.2 billion, but by the time the Hunter programme was terminated, these had risen to $2.1 billion.

The Hunter, produced by IAI and US company TRW, began limited user trials in 1992, with a number of problems surfacing almost immediately. These included an inability to transmit video imagery between air vehicles reliably, failure to meet Army specifications for artillery adjustment support, failure to meet logistical support requirements and lower than hoped for overall system reliability.

Notwithstanding, a $171 million contract was awarded in 1993 for the delivery of an initial seven systems comprising 56 air vehicles. Deliveries began in May 1994. According to GAO reports, acceptance testing of the low-rate initial production units found a range of new problems with software integration, datalinks and engines.

Major setbacks came in August and September 1995 when three air vehicles crashed. Then the GAO released a report warning that overall expenditure on the Hunter production programme had reached $627 million for "a faulty system whose future is uncertain". The DoD, the GAO argued, had shown itself to be "undeterred by the experience with Pioneer" and had proceeded to Hunter production "without subjecting it to operational testing" in advance of an acquisition decision.

The Hunter, the GAO reported, had undergone some 180 major hardware and software design changes in an attempt to solve performance problems, with the initial production systems spending most of their first year on the ground. Acceptance of the first systems took place "only after granting numerous waivers to contract specifications and performance requirements", the GAO said.

Two months later, in December 1995, a separate GAO report recommended that purchase of a naval variant be halted. Navy Hunter, the agency said, was not wanted by the USN, was not capable of being effectively operated from assault carriers, would adversely affect operation of other aircraft types already at sea, did not possess an effective maritime surveillance range and was not capable of carrying all-weather sensor payloads.

By the time the report was released, however, the end of Hunter as an active programme was already in sight. An oversight review launched in June 1995 had concluded the Army short- range component, known as the Maneuver UAV, should be competed for separately.

Another DoD review was warning the integration requirements for non-developmental subsystems had been significantly underestimated, and senior US Army officials were publicly acknowledging that the Hunter had become a cost burden. In January 1996, the DoD quietly let the programme terminate after a total investment of $757 million.

At the same time, the US Army's Maneuver requirement was restructured to form the basis of a new joint TUAV programme that would again seek a common solution for the USN, USMC and US Army. Unlike Hunter, however, the programme would be initially explored under the DoD's advanced concept technology demonstration (ACTD) initiative, then less than two years old.

The Joint TUAV programme, which become known as the Outrider ACTD after the Alliant Techsystems air vehicle had been selected, bore close parallels to Pioneer and Hunter in emphasising what was meant to be a non-developmental solution. Alliant won the 24-month $52.6 million demonstration contract in May 1996 after fending off a large field of candidates that included the Hunter.

The ACTD requirement called for the demonstrated ability to operate for 3-4h at a range of 200km. The full system had to be transportable in a single Lockheed Martin C-130, and the air vehicle to operate on automotive gasoline and be used on board USN assault carriers.

Problems emerged early. The Outrider air vehicle was meant to fly for the first time in November 1996, but did not get airborne until March 1997 because of problems fitting electromagnetic shielding and strengthening the landing gear to meet USN requirements.

This drove up air vehicle size and weight, forcing an increase in take-off and landing distance. In turn, this necessitated the use of arrester cables on assault carrier decks and, as with Hunter, resulted in the likelihood of restrictions being placed on aircraft already operating from those vessels while the UAV was landing.

Naval requirements for the programme also stipulated the use of a heavy fuel engine. According to a September 1997 GAO assessment, the cost of developing an appropriate engine was at that time projected at around $100 million, while the existing gasoline engine was "not performing adequately".

Despite the problems, the DoD was considering exercising options to put the system into low-rate production. Such a move, the 1997 GAO assessment warned, failed to appreciate the time and effort needed to integrate non-developmental items, and as with both Pioneer and Hunter, was in danger of committing new funds without adequate operational test data.

By the time the ACTD drew to a close at the end of 1998, Outrider had shown itself to be capable of only 2h on station at 200km, twoC-130s being required to transport a single system, and the air vehicle needed aviation fuel to operate. No attempt had been made to demonstrate shipboard operations, while post-trials analysis concluded that development of a heavy fuel engine was unlikely to be achieved.

The ACTD results sparked a decision by the USN to set up its own vertical take-off and landing tactical UAV (VTUAV) programme, and a DoD decision to re-open the competition for a TUAV for the US Army, rather than proceed with the Outrider. The GAO's final assessment of the programme, released in August 1999, was gracious. Outrider's key benefit, the agency argued, was to ensure that mistakes already encountered during the Aquila, Pioneer and Hunter programmes were not repeated.

The Outrider experience contrasts with the USAF's General Atomics Predator medium-endurance programme, which began as an ACTD and is arguably one of the most successful TUAV developments undertaken to date.

Tactical dilemma

But the USA has not been alone in its difficulties. When BAE Systems' (formerly GEC Marconi) Phoenix TUAV was accepted into British Army service in December 1998 it was nine years behind the in-service date originally specified when the programme was launched in 1985.

What had begun as a four-year development effort stretched to almost 14 years, during which the Phoenix survived at least one major review of alternatives. Total costs have escalated to an estimated £259.4 million ($387 million). Since the UAV entered service, operational experience has proven the platform, and the British Army is planning a series of further upgrades.

The USA is hoping not to repeat past mistakes as it undertakes development of the US Army's AAI Shadow 200 TUAV and the USN's Northrop Grumman Fire Scout VTUAV. Both are based on proven vehicles, but already there are warning signs of difficulties ahead. The first Fire Scout prototype crashed in November and the GAO has already warned that the DoD is moving into Shadow 200 production too soon.

In terms of success or failure, tactical UAV programmes share some common themes that are ignored at the developer's peril:

The more a UAV is asked to do, the harder it is to develop. Off-the-shelf technology is not necessarily mature technology and can pose the same risks as developmental solutions. A UAV is not just an air vehicle, it is a complete system and must be developed as such.

All dogs must have their day, and despite their track records, the Phoenix and the Hunter had minor triumphs in the Kosovo campaign. Meanwhile, with the Shadow 200 and Fire Scout running into problems despite the best of efforts, the tactical mission remains one of the most challenging for UAVs.

Source: Flight International