A media war of words has broken out between the US Air Force's top acquisition authority and Northrop Grumman over the performance of the airframer's Global Hawk - just days before the Defense Acquisition Board is to open a review of the unmanned aircraft programme.

David Van Buren, USAF assistant secretary for acquisition, in a rare, on-the-record roundtable with reporters, gave a laundry list of reasons why he - and the air service - is unhappy with nearly every aspect of the programme: the high cost, the lengthy testing and delivery period, the programme's pace, the sensors on the aircraft and even the aircraft itself.

"Testing and delivery has been slower than expected," authoritative defence acquisition blog DOD Buzz quoted Van Buren as saying of Block 30 of Global Hawk. "I am not happy with the pace of that programme and we are not happy with the cost of the air vehicle."

RQ-4 Global Hawk Block 30
 © USAF

Northrop quickly countered, arguing that the USAF is well aware of overall cost reductions on Global Hawk's Block 20, 30 and 40 systems and associated payloads. "While there have been cost spikes within production lots due to the quantity procured within each lot, overall cost of the air vehicle and the sensors is trending down, as the company predicted and expected," the company says.

"Additional cost reductions have been identified by the company and will be evaluated for suitability."

On 23 June, as the Defense Acquisition Board prepared to review the programme, Northrop took another swipe at Van Buren's comments and restated the company's commitment to respond to USAF requests within 60 days of notification.

Gary Ervin, corporate vice-president and president of Northrop Grumman Aerospace Systems, said: "Global Hawk is performing 24 hours a day, seven days a week. It's conducting combat and civil missions around the world, while at the same time the air force is putting it through test and evaluation paces here at home to vet the system for final production.

"Global Hawk is performing well in these tests. Its unprecedented performance proves its value to our customers every day with a 95% on-station record, low sustainment and operating costs and high value intelligence.

"Frankly, it outperforms any other high-altitude intelligence, reconnaissance and intelligence system in theatre today. It's in a class of its own."

Following the 11 September terror attacks, two demonstration aircraft were pressed into surveillance service. Since then, Global Hawk has continuously flown more than 1,665 combat sorties totalling 33,280 combat flight hours, averaging 15h on station per sortie and collecting more than 606,000 images, earning an overall performance rating of more than 95%, says Northrop.

In addition to combat efforts, Global Hawk has also flown humanitarian missions over Haiti following the earthquake there and conducted science missions over the North Pole for NASA.

The Euro Hawk derivative is set to begin flight tests soon, and will be deployed to Germany later this year under a deal with the German defence ministry.

Source: Flight International