October 17th, 2007

Yesterday, the NTSB cited a wide range of safety issues as a result of its first investigation of an unmanned aircraft accident. NTSB chairman Mark V. Rosenker said the recommendations address “a wide range of safety issues involving the civilian use of unmanned aircraft.”

The investigation involved the April 25, 2006 accident in which a turboprop-powered Predator B operated on a surveillance mission by the United States Customs and Border Protection (CPB) crashed in a sparsely populated residential area near Nogales, Arizona.

I found several things interesting about the report. First of all, there was no “cockpit” voice recorder. Even though pilots of UAVs are in remote control stations, there are no recorders that can give investigators a record of communications between each other, other pilots and air traffic control. It makes sense that these requirements should extend to UAVs.

Second, the NTSB determined that the probable cause of the accident was the pilot’s failure to use checklist procedures when switching operational control from a console that had become inoperable due to a “lockup” condition, which resulted in the fuel valve inadvertently being shut off and the subsequent total loss of engine power.

The NTSB discovered that the “lockup” condition had been experienced before, but not corrected.

The FAA would not let any other aircraft take off with a known problem with the pilot’s control system. Why would anyone think it was OK to do so with an unmanned aircraft?

We shouldn’t allow a lower level of maintenance standards on unmanned aircraft. Equally important, we should not allow a lower level of operational procedures or airworthiness requirements.

http://www.amtonline.com/interactive/2007/10/17/unmanned-aircraft-accident-investigation/