Pilot Counsel

In-flight interception

July 1, 2001

Not surprisingly, a recent disaster has spurred pilots to want to learn (or refresh) what they must do to minimize the risk of getting shot down during an in-flight interception. In case you missed it, about three months ago a Peruvian military jet intercepted and shot down an innocent civilian single-engine Cessna 185 on floats (U.S. registered) over the Amazon River in Peru. The attack killed a missionary from Michigan and her 11-month-old daughter, and seriously injured the pilot. Her husband and their 6-year-old son survived the attack.

Such a shoot-down is a violation of international law that is intended to protect us civilian fliers and our passengers. But my expression of outrage won't help the next civilian pilot whose aircraft is intercepted, legally or illegally, to cope with the intercept situation. Rather, I think it's more urgent right now to recognize that any civilian aircraft is potentially subject to interception, within or outside the United States. A pilot needs to be able to recognize, in very short order, that he or she is being intercepted. A pilot needs to understand and comply with the instructions from the threatening intercepting aircraft. A pilot needs to be able to respond intelligibly to the intercepting aircraft so that there is no miscommunication. These things will minimize the chances of getting shot down. As for my outrage, we can try to deal with the legal niceties of the intercept once the aircraft and its occupants are safely on the ground.

The in-flight intercept procedures are standardized and internationally recognized. That comes about because all of the civilized nations of the world have agreed to, or adhere to, the Convention on International Civil Aviation. The convention created the International Civil Aviation Organization (ICAO) that adopts international standards and recommended practices to cover all phases of international civilian flying. For your reference, the ICAO in-flight intercept procedures are contained in Rule 3.8, "Interception," of Annex 2 to the convention titled "Rules of the Air" and Appendix 1 and 2 to the rule. They are incorporated into the Aeronautical Information Manual (AIM) published by our own FAA.

The ICAO rule intends to provide uniformity and, above all, safety. It states: "Interception of civil aircraft shall be governed by appropriate regulations and administrative directives issued by contracting states in compliance with the Convention on International Civil Aviation, and in particular Article 3(d) under which contracting states undertake, when issuing regulations for their state aircraft [including military, police, customs, etc.], to have due regard for the safety of navigation of civil aircraft. Accordingly, in drafting appropriate regulations and administrative directives due regard shall be had to the provisions of [the procedures in the appendices]."

The rule says: "The pilot-in-command of a civil aircraft, when intercepted, shall comply with the standards [of Appendix 2], interpreting and responding to standardized visual signals from the intercepting aircraft as specified in [Appendix 1]." We'll explain these procedures in more detail as we go along. The procedures don't anticipate every possible situation, but they do a good job of covering the likely ones. As we will see, the procedures minimize the potential for in-flight conflict by requiring that the intercepted aircraft give deference to the intercepting aircraft.

How does a pilot know that his or her aircraft is being intercepted? According to the ICAO procedures, an intercepting aircraft is supposed to take up a position slightly above and ahead of, and normally to the left of, the intercepted aircraft. The intercepting aircraft is supposed to rock its wings and flash its navigation lights at irregular intervals. These actions by the intercepting aircraft mean: "You have been intercepted. Follow me." If the intercepting aircraft is a helicopter, it will flash its landing lights. If the intercepted aircraft is a helicopter, the intercepting aircraft's position normally should be to the right of the intercepted aircraft.

A rocking nearby aircraft with flashing lights should obviate any doubt that there has been an interception. What should the intercepted aircraft do? According to the ICAO procedures, an aircraft that has been intercepted by another aircraft should immediately do the following four things:

  • Follow the instructions given by the intercepting aircraft, initially interpreting and responding to the standardized visual signals. The intercepted aircraft, in order to communicate to the intercepting aircraft that it understands and will comply with the intercepting aircraft, should rock the aircraft (its wings, in the case of a fixed-wing aircraft), flash its navigation lights (helicopter landing lights), and follow the intercepting aircraft.
  • Then it should try to communicate by radio. It should notify, if possible, an appropriate air traffic control facility.
  • It should attempt to establish radio communication with the intercepting aircraft on the emergency frequency of 121.5 MHz. Until radio communication has been established, the intercepted aircraft should continue to comply with and use visual signals.
  • If transponder equipped, the intercepted aircraft should squawk transponder code 7700.

The intercepting aircraft could be flying racetrack patterns. If so, that is because the intercepted aircraft is too slow to keep pace in following the intercepting aircraft. If the intercepting aircraft rocks each time it passes the intercepted aircraft, understand that this means that this is still an interception. Acknowledge and keep following.

The intercepted aircraft should continue to monitor communications from the intercepting aircraft, visually and by radio. The most welcome signal will be: "You may proceed." If it is not given by radio communication, it is given visually by an abrupt breakaway maneuver from the intercepting aircraft, usually a climbing turn of 90 degrees or more. The intercepted aircraft should acknowledge by rocking the aircraft.

Less welcome will be an instruction to land. It is given by the intercepting aircraft's lowering its landing gear (if equipped), showing a steady landing light, and overflying the runway or helicopter landing area to be used. In the case of an intercepting helicopter, it makes a landing approach and comes to a hover near the landing area. To acknowledge this instruction to land, the intercepted aircraft should lower its landing gear (if so equipped), show a steady landing light, and follow the intercepting aircraft.

The situation gets more complicated, and perhaps more dangerous, if the landing area is not deemed safe by the intercepted aircraft. The intercepted aircraft should indicate that by raising the landing gear and flashing its landing lights while passing over the runway or helicopter landing area. Hopefully, the intercepting aircraft will understand this standardized visual signal. The intercepting aircraft should then lead the intercepted aircraft to another, safer landing area, or let it go. An abrupt breakaway means: "Understood. You may proceed." If the intercepting aircraft retracts its landing gear, rocks its wings, and flashes its navigation lights, it intends to lead the intercepted aircraft to an alternate, presumably safer, landing area.

There are two other visual signals a pilot should know. "Cannot comply" is communicated by regular switching on and off of all available lights. "In distress" is communicated by irregular flashing of all available lights.

Here is a potentially dangerous situation. What if the intercepted aircraft is getting conflicting instructions — that is, the visual signals from the intercepting aircraft are in conflict with the instructions being given by radio? According to the ICAO procedures, the intercepted aircraft should request immediate clarification while continuing to comply with the visual instructions given by the intercepting aircraft. Good guidance, since the intercepting aircraft is the most dangerous threat at the moment.

What if the intercepted aircraft is getting conflicting radio instructions, as for example, conflict in instructions from the intercepting aircraft and from air traffic control or some other source? The guidance of the ICAO procedures is similar. The intercepted aircraft should request immediate clarification while continuing to comply with the radio instructions given by the intercepting aircraft.

These are the ICAO procedures. The procedures in the U.S. AIM are virtually the same except that the ICAO procedures regarding flashing lights apply day or night. On the other hand, the U.S. AIM eliminates the daytime flashing of lights in some instances. Also, there is some confusion in the AIM about the position of an intercepting aircraft, whether it should be on the left or on the right. To me, these are inconsequential differences. The AIM does not say that flashing lights during the daytime in the instances specified in the ICAO procedures is not allowed. Therefore, memorizing and using the ICAO procedures is appropriate and simpler. And whether the intercepting aircraft takes up a position on the left or the right should not change how the intercepted aircraft responds.

I mentioned earlier that the ICAO procedures cannot contemplate every conceivable situation. Remember, rock the aircraft wings, flash the lights, and follow. That should signal the intercepting aircraft that you intend to comply until released, whatever the situation. That should minimize the chances of hostile action by the intercepting aircraft.

What happened in Peru? We'll get into that next month.