Contracting Civilians for Remotely Piloted Aircraft System Operations

Blurring International Law’s Principle of Distinction?

By Lieutenant Colonel

By Lt Col



, GE


Joint Air Power Competence Centre

 June 2016


Afghanistan, 21 February 2010, 5 a.m.: A convoy of three vehicles is travelling along dark mountain roads heading towards a special operations team tasked to capture insurgent forces suspected of operating in the area. A fully armed Predator Remotely Piloted Aircraft (RPA) is watching over them, cameras and sensors focussed on the suspicious convoy. Intelligence analysts and video screeners verify 21 military-aged males carrying what appear to be ‘possible weapons’. As the Predator continues tracking the vehicles, cell phone calls in the area are intercepted and translated. According to linguists providing intelligence support, the phone calls indicate a Taliban unit is in the area and preparing for an attack. The ground force commander concludes he has the positive identification necessary to engage a hostile force and calls for an airstrike. The Predator unleashes two Hellfire missiles. They slam into the first and third vehicles, which burst into flames. Dead and wounded are everywhere. Very soon, the RPA crewmembers and video screeners realize something has gone horribly wrong. The investigation that soon followed would reveal that at least 15 Afghan civilians had been killed, to include one woman and three children, and twelve wounded. They were travelling together as a group for safety through the insurgent stronghold region of Uruzgan Province. Some were businessmen, others students returning to school, and a few were simply travelling to visit family. No disciplinary action, however, was taken against the primary screener from Florida who provided imagery analysis that contributed to the decision to attack. There wasn’t much that the military could do – she was a civilian contractor.1

This abbreviated narrative clearly demonstrates civilian contractors are deeply interwoven into present-day military operations. Remotely Piloted Aircraft Systems (RPAS) have opened the door even wider for such civilian participation, even becoming an integral part of the targeting process. A thin line separates civilian intelligence analysts from direct civilian participation in hostilities, which may violate domestic or international law. This article outlines the challenges arising from civilian involvement in RPAS operations, examines the extent to which civilians should or should not be contracted to perform RPAS tasks, and recommends good practices to ensure compliance with international law.

The Past and Present Role of Civilians in Combat

Throughout history, civilian populations have contributed to general war efforts. These contributions have included the production and supply of weapons, equipment, food, and shelter, or economic, administrative, and political support. However, such activities typically remained distant from the battlefield. Although nations have often employed civilian contractors to fulfil combat and combat support functions, their employment had been most prevalent in the technical and support categories. George Washington hired civilians to haul the Continental Army’s equipment. Supply vendors followed the Union and Confederate armies during the Civil War. In the Vietnam War, technological innovation increasingly required the presence of contractors on the battlefield to maintain and repair sophisticated equipment. Ever greater reliance on contractors has come as a direct result of downsizing the military forces following the Cold War. Today, contractors are an integral part of complex weapons systems support and, to a large degree, they are responsible for functions once performed by uniformed personnel.2,3,4

The complexity of remotely piloted systems amplifies the reliance on contractor-provided technical field support. Most major RPAS manufacturers regularly deploy civilian teams to combat zones to support their military customers. This support typically includes ‘traditional’ repair and maintenance services. It also may include launch and recovery support as well as piloting the aircraft and operating its sensors. Quite a few nations currently contract civilian RPA pilots and operators to conduct unarmed Intelligence, Surveillance and Reconnaissance (ISR) missions with a very low probability of combat involvement.5

The Issue of Civilian Participation in Combat

The primary aim of International Humanitarian Law (IHL) is to ‘protect the victims of an armed conflict by regulating and balancing the conduct of hostilities between military necessity and humanity.’6 The principle of distinction lies at the heart of IHL. National armed forces participating in a conflict must be clearly distinguishable from civilians, who are presumed to not be taking part in combat operations and are therefore protected against direct attack. Outsourcing military functions to contractors increases the risk of blurring that principle.7 Hence, careful consideration must be given as to what extent civilians should perform military tasks and where direct participation in combat begins. Furthermore, consequences of crossing that line should be considered not only for the contracting state, but also for the individual civilian.

RPAS Functions and their Direct Participation in Combat

As already mentioned, civilian contractors currently perform almost the entire spectrum of RPAS functions, with the exception of target designation and weapons employment, both of which would obviously be considered direct participation in combat. For other functions, such as battlefield repair and maintenance, configuring munitions, launch and recovery, piloting and operating sensors, intelligence analysis, or target identification, it is more difficult to conclude whether they qualify as direct participation in combat.

To determine whether an individual is ‘directly participating in combat’, the International Committee of the Red Cross (ICRC) issued the ‘Interpretive Guidance on the Notion of Direct Participation in Hostilities under International Humanitarian Law’. It states ‘direct participation in hostilities refers to specific hostile acts carried out by individuals […] and must be interpreted synonymously in situations of international and non-international armed conflict.’ Simply put, it means participation in combat operations or activities to support one party by weakening the enemy’s military capacity. The ICRC guidance delineates three elements which have to be met in conjunction to consider an individual act as direct participation in hostilities: the threshold of harm, direct causation, and belligerent nexus.

Threshold of Harm

‘To reach the required threshold of harm, a specific act must be likely to adversely affect the military operations or military capacity of a party to an armed conflict or, alternatively, to inflict death, injury, or destruction on persons or objects protected against direct attack.’8

Hence, a specific RPAS function does not necessarily have to inflict actual death, injury, or destruction on persons or objects to reach the required threshold of harm. It is sufficient if the function can reasonably be expected to cause an adverse effect to the opposing party. Even unarmed activities, such as electronically disrupting communications would reach the required threshold of harm. An adverse effect to the opposing party may also be achieved in a causal chain by, for example, transmitting tactical targeting information for an attack.9 However, for those causal effects of RPAS functions, the principle of direct causation has to be considered.

Direct Causation

‘For the requirement of direct causation to be satisfied, there must be a direct causal link between a specific act and the harm likely to result either from that act, or from a coordinated military operation of which that act constitutes an integral part. […] Where a specific act does not on its own directly cause the required threshold of harm, the requirement of direct causation would still be fulfilled where the act constitutes an integral part of a concrete and coordinated tactical operation that directly causes such harm.’10

A standard RPAS mission typically consists of six principal steps: Find, Fix, Track, Target, Engage, and Assess (F2T2EA). These six steps represent the linear sequence of events used to engage targets. Operators and analysts constantly screen video feeds and images streamed from the RPA to find potential targets. Once identified, operators and analysts fix the target by determining its precise location, typically utilizing the RPA’s advanced sensor suite. Once the target’s location is established, operators and analysts continue to track the target. At this stage of the mission, the focus shifts from what might be considered passive surveillance to active coordination with ground troops, who will confront the target, or with the execution of kinetic air strikes against the target. Based on collected intelligence, mission commanders make their decisions and kinetic capabilities may be applied against the target while the RPAS loiters above to assess.11 Therefore, any function within or attached to the RPAS directly related to the F2T2EA process can be considered to meet the requirements for direct causation.

Belligerent Nexus

‘To meet the requirement of belligerent nexus, an act must be specifically designed to directly cause the required threshold of harm in support of a party to the conflict and to the detriment of another.’12

It can be assumed that military RPAS operations in international as well as in non-international armed conflict are typically conducted in support of friendly armed forces and to gain a military advantage over the opponent by utilizing the RPA’s sensors and, possibly, weapons. Therefore, any function within the unmanned system can be qualified as meeting the requirement of belligerent nexus.

Consequences of Civilian Participation in Combat

IHL recognizes two categories of individuals during armed conflict: combatants and civilians. With few exceptions, combatants include only members of organized armed forces. As such, they are provided with so-called ‘combatant privilege’, i.e. the right to lawfully participate in combat and immunity from domestic prosecution for those acts as long as they are in accordance with IHL. Furthermore, combatants are considered prisoners of war if captured and are entitled to the protections of the Geneva Conventions and supplemental Protocols.

Civilians are described as individuals not participating in armed conflict and who enjoy immunity from attack ‘unless and for such time as they take a direct part in hostilities’. IHL neither prohibits nor privileges civilian direct participation in hostilities. However, civilians directly participating in hostilities are not entitled to the combatant privilege, do not enjoy immunity from domestic prosecution for lawful acts of war, and will lose the protection against direct attack. Therefore, civilians, if captured, may be prosecuted and punished to the extent that their activities or the harm caused by them is penalized under national law.

Furthermore, civilians directly participating in hostilities can be expected to not carry arms openly (if at all) or otherwise distinguish themselves from the civilian population. This may lead to significant confusion and uncertainty during the implementation of the principle of distinction and entail erroneous or arbitrary targeting of the civilian population. This may also lead an adversary to believe that civilian RPAS personnel are entitled to protection against direct attack, which may amount to perfidy in violation of IHL.

Contracting States’ Responsibilities and Good Practices

As discussed above, contracting civilians for operating RPAS, even if they participate in combat, is not explicitly prohibited by IHL. But it does entail some serious consequences for those individuals involved. Therefore, the ICRC’s so-called ‘Montreux Document’ provides guidance on legal obligations and good practices if nations contract civilian personnel for military functions during armed conflict. Some recommendations from the Montreux Document which are applicable to RPAS personnel are listed below.13

  • States retain their obligations under international law, even if they contract civilians to perform certain activities.
  • States have an obligation to ensure respect for international humanitarian law by civilians they contract.
  • States should determine which services may or may not be contracted out while taking into account whether a particular service could cause civilian personnel to become involved in direct participation in hostilities.
  • States should allow for a clear distinction between contracted personnel and the civilian population.
  • States should provide appropriate administrative mechanisms to ensure the proper execution of the contract and the accountability of contracted personnel for their improper and unlawful conduct.


The involvement of civilians in armed conflicts and the reliance on private entrepreneurs during war is nothing new. Indeed, the increased use of RPAS in modern warfare has opened the door for an even wider range of civilian participation in armed conflict. Contracting civilian personnel to operate RPAS or to perform functions within the F2T2EA process is not explicitly prohibited by IHL, but it considerably blurs its principle of distinction. If that line is crossed, contracted civilian individuals will lose their protection against direct attack, and might be exposed to domestic prosecution for their activities, potentially even by their own nation. Although remote operations from inside the home territory provide a decent level of protection against such consequences, states contracting civilians for RPAS should carefully consider their obligation to protect civilians from the effects of war and preserve the IHL principle of distinction. Should nations determine that the use of civilians in RPAS operations is required, they should comply with the legal obligations and good practices outlined in the ICRC’s Montreux Document, especially the ones listed in this article.

Maj Keric D. Clanahan, ‘Wielding a Very Long, People-Intensive Spear: Inherently Governmental Functions And The Role Of Contractors In U.S. Department Of Defense Unmanned Aircraft Systems Missions’, The Air Force Law Review, Volume 70, 2013.
Gary Schaub, Volker Franke, ‘Contractors as Military Professionals?’, US Army War College, Strategic Studies Institute, 2009.
Marc Lindemann, ‘Civilian Contractors under Military Law’, US Army War College, Strategic Studies Institute, 2007.
‘Contractors on the Battlefield’, Lexington Institute, 2007.
W. J. Hennigan, ‘Air Force hires civilian drone pilots for combat patrols; critics question legality’, Los Angeles Times, 27 Nov. 2015.
International Committee of the Red Cross (ICRC), Legal Adviser, ‘Interpretive Guidance on the Notion of Direct Participation in Hostilities Under International Humanitarian Law’, May 2009.
Ibid. 6.
Ibid. 6.
International Committee of the Red Cross (ICRC), Legal Adviser, ‘Second Expert Meeting on the Notion of Direct Participation in Hostilities’, Oct. 2004.
Ibid. 6.
Ibid. 1.
Ibid. 6.
International Committee of the Red Cross (ICRC), ‘The Montreux Document – On pertinent international legal obligations and good practices for States related to operations of private military and security companies during armed conflict’, Sep. 2008.
Content Navigation
Lieutenant Colonel
Joint Air Power Competence Centre

Lieutenant Colonel Haider began his military career with the German Armed Forces in April 1992. He initially served as a Personnel NCO in the 150th Rocket Artillery Battalion HQ. Following his promotion to Lieutenant in 1998, he took on the role of an MLRS platoon leader within the same battalion. After three years, he transitioned to the position of CIS Branch Head at the 150th Rocket Artillery Battalion HQ. Subsequently, Lieutenant Colonel Haider was assigned to the 325th Tank Artillery Battalion, where he served as a battery commander before assuming command of the maintenance and supply battery. In 2008, he was appointed as the commander of the maintenance and supply company within the 284th Signal Battalion. His responsibilities expanded in 2010 when he became the Deputy Commander of the German support staff for the 1st NATO Signal Battalion. As a follow-on assignment, he served as the Deputy Battalion Commander of the 132nd Rocket Artillery Battalion.

Since 2012, Lieutenant Colonel Haider has been a Subject Matter Expert for Unmanned Aircraft Systems and Countering Unmanned Aircraft Systems within the JAPCC Combat Air Branch. Lieutenant Colonel Haider represents the JAPCC in and contributes to several key NATO groups, including the NATO Joint Capability Group Unmanned Aircraft Systems, the NATO Counter-UAS Working Group, and the NATO Joint Capability Group Maritime Unmanned Systems.

Information provided is current as of April 2024

Other Articles in this Journal

Leadership Perspective

Fit for the Future

Interview with Lieutenant General Alexander Schnitger, Commander of the Royal Netherlands Air Force

Transformation & Capabilities

How NATO Makes the Unknown Known

A Look at the Improvements to NATO Joint Intelligence, Surveillance and Reconnaissance

Air Command and Control in the Amphibious Environment

Institutionalizing Counter-Improvised Explosive Device Lessons Learned from Afghanistan

An Overview – Part 2

Nimble Titan

Ballistic Missile Defence in a Regional, Cross-Regional and Global Environment

Air Strikes Against Terrorist Leadership

Three Lessons from the US Air Force Special Operations Command


Knowledge Development vs. Intelligence in NATO

A Problematic Delineation and its Ramifications

Assessing Nations for NATO Partnerships

A Country Baseline Assessment Methodology

What’s Past is Prologue

Why the Golden Age of Rapid Air Superiority is at an End

Out of the Box

The Changing Arctic and its Impact to NATO Joint Air Power

Laser-Based Space Debris Removal

An Approach for Protecting the Critical Infrastructure Space

Breaking Integrated Air Defence with Unmanned Aerial Vehicle Swarms

Developing and Testing the US Employment Concept

Contact Us

Contact Information

Joint Air Power Competence Centre
Römerstrasse 140
47546 Kalkar

+49 (0) 2824 90 2201

Request for Support

Please leave us a message

Contact Form