The F-20 began as a modest idea: re-engine the successful F-5E Tiger II to keep Northrop’s export line competitive into the 1980s. Northrop studied new powerplants from the mid-1970s and settled on a single General Electric F404, the design that would define the aircraft. Under President Carter’s 1977 arms-transfer policy, the United States wanted to sell allies a purpose-built, deliberately limited “FX” export fighter instead of frontline types — and the re-engined Northrop, initially called the F-5G, was the leading candidate for that role.

Crucially, Washington would not pay for it. So Northrop financed the aircraft itself, betting that export demand would repay the investment. When the US military assigned it the out-of-sequence designation F-20 in 1982 — a deliberate signal that it was a genuinely new aircraft, not just a modified F-5 — the company had already committed to one of the boldest private gambles in Cold War aviation. The bet depended entirely on the export door staying the shape Carter had cut. It did not.

On its own numbers the Tigershark was a bargain. Northrop offered it at roughly $15 million a copy, with dramatically lower running costs than an F-16 and performance close enough that many pilots who flew it came away impressed. For a small air force that only needed air defence and light strike, it was arguably the more sensible buy.

But defence procurement is rarely decided on the airframe alone. The F-16 had the decisive advantages of scale and politics: it was already in mass production, flown by the US Air Force and a growing club of allies, backed by an enormous spares and upgrade ecosystem, and — once Washington allowed it — available for export on competitive terms. Buying the F-16 meant joining a huge, well-supported user base with a clear upgrade path; buying the F-20 meant being the lone customer for an orphan aircraft. Against that, 80% of the capability at half the cost was not enough.

Two of the three Tigersharks were lost during overseas sales tours. On 10 October 1984, the first prototype crashed at Suwon Air Base, South Korea, killing Northrop test pilot Darrell Cornell. On 14 May 1985, a second aircraft crashed at Goose Bay, Canada, killing pilot David Barnes. Both were demonstration flights involving sustained high-G aerobatic sequences.

The investigations reached the same sober conclusion in each case: there was no evidence of any aircraft or system failure. Instead, both pilots were assessed to have suffered G-induced loss of consciousness (G-LOC) during demanding manoeuvres flown to impress prospective customers. The findings cleared the airframe, but the loss of two of three demonstrators — and two respected pilots — was a heavy blow to a campaign that was already struggling to convert admiration into orders.

The Tigershark’s economics were its entire selling point — and, ultimately, its tragedy. Northrop marketed the aircraft at roughly $15 million per airframe, undercutting the F-16 while promising far lower operating costs: fewer maintenance man-hours per flight hour, higher availability and quicker turnaround. For a small nation it was pitched as a fighter you could not only buy but genuinely afford to run.

Because the F-20 never entered service, there is no reliable published cost-per-flight-hour figure for it — any number quoted is a manufacturer projection rather than fleet experience. The one hard financial fact is the one that sank the company’s ambitions: Northrop is reported to have spent on the order of $1.2 billion of its own money developing and marketing the Tigershark, and recovered essentially none of it, having sold zero aircraft. It was among the largest private-venture losses in the industry’s history.