Northrop Grumman’s new version of the RQ-4B Global Hawk Block 30 drone has been declared operationally ineffective in a Pentagon’s weapons tester report.

The report said the drone was “not operationally effective for conducting near-continuous, persistent intelligence, surveillance and reconnaissance (ISR) missions that it was designed to conduct.”

“Global Hawk long endurance flights do not routinely provide persistent ISR coverage due to low air vehicle reliability,” the report added.

Multiple deficiencies with the plane’s airframe and sensor equipment highlighted in the report include the electrical generator, navigational unit and adhesives used to secure nut plates.

The Enhanced Imagery Sensor Suite either met or exceeded most operational requirements for imagery intelligence, however the Airborne Signals Intelligence Payload (ASIP) failed to consistently deliver actionable signal intelligence.

About 16 recommendations have been suggested in the report including upgrading communication systems, developing de-icing systems and improving operator training programs for the ASIP sensor.

The US Air Force has already bought 16 of 42 planned Block 30 drones, according to Bloomberg.