UAV - Unpiloted Aerial Vehicle
Air Traffic Control Fully Certified
Communication Breakdown; Training / Qualification
Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance
General None Reported / Taken
Human Factors; Aircraft
While working an adjacent sector I witnessed a UAV deviate from his assigned altitude. This UAV was cleared to maintain FL350. The aircraft descended out of FL350 to FL300 without a clearance. When questioned by the controller; the remote pilot stated that he could not maintain FL350 so he descended. I feel this event happened due to the training of the remote pilots of the unmanned aircraft. I had no role in the event other than witness. I was informed by the controller and the FLM that they were not going to file any paperwork on the event. The accountability and standards for unmanned aircraft remotes should be equal to the standards of the commercial pilots. Also unmanned aircraft must be held to the same restrictions as manned aircraft. For example; in the Global Hawk System; if the aircraft loses data link it will fly its programmed flight plan. It will not maintain its last assigned altitude. In this example positive separation can not be maintained.
ZMP Controller reports a UAV descending out of FL350 to FL300 without clearance. When questioned by the Controller the remote pilot stated that he could not maintain FL350 so he descended.