By Marina Malenic

Air Force leaders have raised concerns about Northrop Grumman‘s [NOC] performance on the RQ-4 Global Hawk unmanned surveillance aircraft program, faulting the company for testing schedule slips and problems with the system’s sensors, according to sources and documents.

Northrop Grumman was notified on April 7 of Air Force concerns with the RQ-4 Global Hawk unmanned aerial system (UAS) development program in a letter signed by Sue Payton just prior to her resignation as assistant secretary of the Air Force for acquisition. In the letter, Payton criticizes the company for its failure to maintain the program’s Initial Operational Test & Evaluation (IOT&E) schedule and for problems with the aircraft’s Enhanced Integrated Sensor Suite.

According to sources, Payton’s letter was not supported by key uniformed leaders in the acquisition community involved with the Global Hawk.

Gary Ervin, president of the company’s Aerospace Systems operating sector, addressed the concerns in letters sent last week to Air Force Secretary Michael Donley and acting Air Force acquisition chief David van Buren.

“The magnitude of the current IOT&E slip is only partially a result of development delays caused by hardware or software adjustments,” Ervin writes in an April 20 letter to van Buren. “NGC acknowledges the delays; however, as we discussed at our meeting with you… in February 2009, there are several contributory factors with one of the most significant causes of the delay being the government’s change in test schedule planning methodology.

“We take pride in the design, workmanship and production processes on Global Hawk and are very concerned that [Payton’s] letter references them as being ‘questionable,'” he adds.

Northrop Grumman admits, however, it is not blameless for some of Global Hawk’s woes.

“Unplanned delays to Air Worthiness Certification (AWC) have in fact contributed to the delayed start of IOT&E and it may be worthwhile re-evaluating the extent of AWC requirements and the certification process,” the letter to van Buren states. “The collaboration between the 303rd [Aeronautical Systems Group] and the NGC team on AWC acceptance was at times inefficient.”

The letters state that Northrop Grumman plans to expand its flight testing support staff.

“NGC recognizes that the most important resource for successful program execution is qualified personnel,” Ervin writes to van Buren. “The recent consolidation of the Space Technology and Integrated Systems sectors of NGC into one Aerospace Systems sector brings additional talent that will be applied as necessary to new contract work.”

Ervin also writes to van Buren: “We understand your concern regarding the Enhanced Integrated Sensor Suite (EISS) sensors, but we believe the types of anomalies encountered are normal for a development program.”

“Your continued support of the Global Hawk program is critical,” he writes in the April 21 letter to Donley. “We believe that some congressional representatives and their staffs may recommend cuts to production funding as a result of a recently announced replan to the Global Hawk operational rest schedule and amidst erroneous concerns, like those of Ms. Payton.”

The letter to Donley concludes with Ervin pledging a new series of weekly meetings on the program with the Air Force Secretary’s staff.

“Delaying initial operational test and evaluation to expand routine flight test activities will delay fielding systems overseas, jeopardize future production and modernization efforts and put our fighting men and women at risk” the company said in response to a press query.

Northrop Grumman added it was “pleased to report the current Air Force acquisition leadership is working in a partnership with Northrop Grumman to address Ms. Payton’s concerns.”