"Invisible killers" that could bring down an airliner

Unmanned aerial vehicles (UAVs), also commonly referred to as drones, are becoming a significant part of most military repertoires.

At least 32 countries are known to be developing UAVs, with the US being the operator of the largest fleet; the US military’s inventory of unmanned aircraft has increased from 50 to 7,000 in the last ten years.

These UAVs provide vital missions for military operations and, given the volatile nature of security in the Middle East, they are playing an integral role within the military forces. This is particularly the case in Iraq, Afghanistan and Pakistan, where drones are commonly used for intelligence, surveillance and reconnaissance (ISR) missions in support of counter-insurgency operations on the ground.

These UAVs are small compared to an airliner and most are designed by nature to be undetectable; they don't always show up on radar and are not fitted with traffic collision avoidance systems (TCAS). All in all, they are the commercial pilots’ worst nightmare; a pilotless aircraft that his instruments cannot detect and which he can hardly see, if he’s looking out of the window to see one in the first place.

The Middle East and the GCC in particular have a vibrant aviation industry with some of the fastest growing airlines in the world. The Middle East is in prime position to both serve the East and the West, as well as attracting air travellers to the region for business and for pleasure. Investment in aviation is set to continue with the introduction of an aerospace park in Al Ain which will, among other activities, be manufacturing aero-structures for some of the world’s leading aircraft manufacturers.

Furthermore, Al Maktoum International Airport, currently still in construction in the Jebel Ali area of Dubai, opened for cargo carriers at the end of June 2010, with passenger services expected to start in spring 2011. When complete, the airport is projected to have an annual cargo capacity of 12 million tons and a passenger capacity of more than 120 million.

Additionally, the UAE’s growing aviation industry received a boost at this year’s Farnborough Airshow, where Emirates signed a US$9.1 billion deal for 30 Boeing 777 aircraft, a month after signing a US$11 billion deal with Airbus for 32 additional A380s.

The rest of the Middle East is not far behind with Qatar Airways also placing a US$122 million order from Bombardier at Farnborough, and studies by the International Air Transport Association have found that Middle Eastern air traffic has grown 18 per cent since the summer of 2009.

The indigenous UAV industry in the Middle East has also been growing in parallel to the commercial aviation industry. Finmeccanica announced a joint venture with Abu Dhabi Autonomous System Investments (ADASI) for developing medium altitude UAVs at the Paris Air Show last year. Turkish Aerospace Industries (TAI) recently revealed its own locally designed and manufactured drone, the Anka, at the Farnborough Airshow this year; which is expected to be fully operation by the end of 2012.

With such heavy commercial traffic and military operation of UAVs in the region, there is cause for concern raised by local officials. This has been highlighted by a near miss incident where an airliner departing Baghdad airport was required to take measures to avoid a UAV as well as other rumoured incidents. A mid-air collision between these aircraft would be a major aviation accident, and could not only cause significant civilian loss of life but, given sensitivities within the region, could also inflame societies and breed speculation.

The Iran Air incident springs to mind, where a US Navy guided missile mistakenly shot down a civilian airliner carrying 290 people in 1988, causing much controversy and souring relationships. It has also been reported by the US Customs and Border Protection agency that UAVs, which the agency uses for border surveillance, have an accident rate that is more than seven times greater than that of manned aircraft. Generally speaking, it is also important to bear in mind that the relatively low cost of developing UAVs, as opposed to manned aircraft, has led to excessive availability flooding international airspace, and not all of these vehicles are equipped with sufficient safety and detection capabilities. Additionally strategic UAVs, designed for longer missions, are growing larger in size – some reaching the wingspan of a commercial passenger jet – increasing the potential lethality of a collision.

UAVs and commercial aviation sharing airspace poses many issues for airline pilots. Drones involved in surveillance operate at altitudes of around 20,000ft and above. Airliners cruise at around 30,000ft and will, therefore, encounter these UAVs during climb and descent; periods of increased workload for the pilots. This fact becomes a human factors issue. During these periods the ability to process information is reduced and judgement and decision-making are also affected. Statistics from the last 50 years of commercial aviation show that 92 per cent of aircraft accidents take place at these strenuous times.

Today's commercial aircraft have highly developed flight management systems and automation. Although commercial airline pilots do have ‘line of sight’ observation obligations, during the climb and descent the pilots will be engaged in configuring the flight management systems. Pilots’ attention will be focused on these systems and their heads will be down looking at the displays, not looking out of the window. Given the fact that the UAVs don’t always show up on radar and don’t have TCAS, the pilots are unlikely to spot them, let alone avoid them.

Some UAVs have pre-set flight paths and others are operated remotely with limited visual command; it is likely that the ground operator would have forward or upwards facing cameras capable of only seeing oncoming air traffic, and even this is limited by weather conditions. Presently, no technology has been developed that can fully substitute for human spatial awareness, and for this reason, the responsibility is, currently, really on the pilot to avoid the UAV.

The use of UAVs and associated collision hazards in the Middle East may be growing as the region becomes more commercially busy and border and sea surveillance increases.

How can the risk of collision be avoided? Firstly, it would be beneficial for both sides to be aware of the risk, particularly commercial aviation operators. The aviation industry can start taking measures to deal with this issue; to begin with by recognizing and identifying the risk.

Pilot workload evaluations can assess how the pilots are dealing with this scenario during a simulation. This can lead to procedural changes and training interventions to improve pilots’ abilities to deal with this emerging problem.

Most military missions are secret for obvious reasons; however a notice to airlines that drones may be operating in certain commercial airspace would be helpful, although this may not always be possible in cases of covert operations.

It may also be beneficial, though somewhat disruptive, for the military to book blocks of ‘segregated’ airspace for drones, controlling and restricting access by civilian aircraft to this space.

Another option would be to gather and transmit cooperative air traffic information directly to the UAV operators. This information can be obtained either from military ground-based radars, which can detect all airborne vehicles, or from air traffic control from cooperative airports in the vicinity of the UAV’s flight path.

‘Sense and avoid’ technologies are currently being developed by militaries and defence contractors in order to integrate accurate TCAS capabilities into UAVS without compromising their payloads. In July 2010, the US Air Force Research Laboratory (AFRL) announced that algorithms are being designed to allow UAVs to integrate with manned air traffic and calculate ‘intended’ flight paths of other vehicles. They would allow the UAVs to automatically process air traffic information and make ‘accurate and reliable’ assessments on whether or not a collision is possible.

Overall, developing collision avoidance techniques and technologies is becoming increasingly important, especially for the military as it is projected that in the near future the number of UAVs available will far outnumber the number of trained operators qualified to pilot them.

Additionally, it is also expected that in the foreseeable future unmanned aircraft will be increasingly utilized for commercial cargo transport, crowding international airspace even further. It is therefore imperative that, in addition to creating and spreading awareness, technological research and development currently focuses on creating collision avoidance capabilities that may evade possible major catastrophes in the future.