Attrition: Big UAV Breeds Big Doubts

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May 20, 2012: Four months after an Israeli Heron TP (also known as Eitan or Heron 2) UAV crashed, all Israeli Air Force Heron TPs remain grounded. There appear to be doubts about the durability and reliability of the Heron TP. This has led to government officials considering selling off the few Heron TPs the air force has because this aircraft is too expensive to buy and operate. Israel has less expensive UAVs that get the work done at a lower cost.

A Heron TP crashed on January 29th, two years after it entered squadron service in the Israeli Air Force (with 210 Squadron). The $5 million UAV was testing a new sensor that was hanging from one of the wings. That wing broke off when the UAV made a maneuver that exceeded what the wings were designed for. This was believed the result of a new flight control system that was not finished with all its flight testing. An investigation is still underway to determine if the loss could have been avoided.

The Heron TP's first combat service was two years ago, when it was used off the coast of Gaza, keeping an eye on ships seeking to run the blockade. For that kind of work the aircraft was well suited. But so are smaller and cheaper UAVs.

Development of the Heron TP was largely completed five years ago but this was basically a UAV for the export market, and the Israeli military was in no rush to buy it. There have been some export sales, and the Israeli air force eventually realized that this was an ideal UAV for long range operations or for maritime patrol. But it turned out there were few missions like that.

Equipped with a powerful (1,200 horsepower) turboprop engine, the 4.6 ton Heron TP can operate at 14,500 meters (45,000 feet). That is, above commercial air traffic, and all the air-traffic-control regulations that discourage, and often forbid, UAVs fly at the same altitude as commercial aircraft. The Heron TP has a one ton payload, enabling it to carry sensors that can give a detailed view of what's on the ground, even from that high up. The endurance of 36 hours makes the Heron TP a competitor for the U.S. MQ-9 Reaper (or Predator B), which is the same. The big difference between the two is that Reaper is designed to be a combat aircraft, operating at a lower altitude, with less endurance, and able to carry a ton of smart bombs or missiles. Heron TP is meant mainly for reconnaissance and surveillance, and Israel wants to keep a closer, and more persistent, eye on Syria and southern Lebanon. But the Heron TP has since been rigged to carry a wide variety of missiles and smart bombs.

The Heron TP was sold to France, to serve as a Predator substitute, until a new design can be developed in France. This variant was called Harfang ("Eagle"), and three were purchased three years ago and sent to Afghanistan. Within a year those three had spent 1,400 hours in the air. That's actually quite low, coming out to about one sortie a week per aircraft. There were technical problems with the Harfang and much of the time only one of the three were available for service. The Harfang usually flies missions of less than 24 hours.

Despite the technical problems with the Harfangs in Afghanistan, France ordered a fourth one. Harfang has since been given a more powerful engine and other mods, to become Harfang 2. In addition, there is a maritime patrol version. France has tried to buy Predators but the waiting list was long, and French troops need UAV support right away. European aircraft manufacturers have yet to come up with a world class UAV design (like the American Predator and Reaper, or the Israeli Heron, etc). Israel stands by to supply tried and tested designs like the many models of the Heron.