US NTSB issues recommendations in first investigation of UAV accident
18 Oct 2007
The accident occurred on April 25, 2006, when a turboprop-powered, Predator B, being operated on a surveillance mission by the United States Customs and Border Protection (CPB) crashed in a sparsely populated residential area near Nogales, Arizona. Though no one on the ground was injured, the UA was substantially damaged.
The safety recommendations approved by the Safety Board 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, and a lack of a flight instructor in the Ground Control Station.
Through its recommendations the NTSB board has highlighted several areas of particular interest including: the design and certification of the unmanned aircraft system; pilot qualification and training; the integration of UAs into the air traffic management system; and audio records of all UA operations-related communications.
"This investigation has raised questions about the different standards for manned and unmanned aircraft and the safety implications of this discrepancy," said NTSB chairman Mark V Rosenker. "Why, for example, were numerous unresolved lock-ups of the pilot's control console even possible while such conditions would never be tolerated in the cockpit of a manned aircraft?"
Expressing apprehension about the likely scenario of manned and unmanned aircraft sharing the same airspace, chairman Rosenker said, "The fact that we approved 22 safety recommendations based on our investigation of a single accident is an indication of the scope of the safety issues these unmanned aircraft are bringing into the National Airspace System."
With the investigation revealing that the pilot was not proficient in the performance of emergency procedures, which led to the accident, Rosenker said, "The pilot is still the pilot, whether he is at a remote console or on the flight deck."
"We need to make sure that the system by which pilots are trained and readied for flight is rigorous and thorough. With the potential for thousands of these unmanned aircraft in use years from now, the standards for pilot training need to be set high to ensure that those on the ground and other users of the airspace are not put in jeopardy," he said.
The Safety Board also noted that there was no equivalent of a cockpit voice recorder at the pilot's control console and that the pilot's communications with air traffic controllers and others were not recorded. To enhance the efficacy of future investigations of UA incidents and accidents, the NTSB recommended that the Federal Aviation Administration (FAA) require all conversations, including telephone conversations between unmanned aircraft pilots and air traffic control, other UA pilots, and other assets that provide operational support to unmanned system aircraft system operations, be recorded and retained.
Among the additional safety recommendations sent to the FAA are:
* Require that established procedures for handling piloted aircraft emergencies be applied to unmanned aircraft systems.
* Require that all unmanned aircraft operators report to the FAA all incidents and malfunctions that affect safety; require that operators are analyzing these data in an effort to improve safety; and evaluate these data to determine whether programmes and procedures remain effective in mitigating safety risks.
Among the 17 safety recommendations sent to US Customs and Border Protection are:
* Require that pilots be trained concerning the expected performance and flight path of an unmanned aircraft anytime communication with the aircraft is lost.
* Conduct face-to-face meetings between pilots of unmanned aircraft and working-level air traffic controllers to clearly define responsibilities and actions required for standard and non-standard UA operations.
* Identify and correct the causes of the lockups in the pilot's control console.
* Revise the US Customs and Border Protection's pilot training programme to ensure pilot proficiency in executing emergency procedures.
* Require that a backup pilot or another person who can provide an equivalent level of safety as a backup pilot be readily available during the operation of a UA system.
* Develop a safety plan, which ensure that hazards to the National Airspace System introduced by the US Customs and Border Protection UA system operation are identified and that necessary actions are taken to mitigate the corresponding safety risks to the public over the life of the programme.
