Suggested In-Flight Procedures for
Chemical and Biological Warfare Threats

Since the the hijackings and subsequent attacks on New York and Washington, DC that killed several thousand people, there have been a number of attacks involving the use of anthrax. While the recent anthrax attacks did not directly involve airliners, it is possible that there may be future attacks against airliners involving chemical or biological warfare agents. At present, there are no airline or FAA approved procedures for dealing with either the presence of suspected biological or chemical warfare agents, or with the actual use of such agents in flight.

Recently, a veteran military pilot and current captain with a major U.S. airline submitted an article to that addresses several chemical or biological warfare scenarios and suggests procedures that would limit the effects of such agents. The highlights of the article are below, and the complete article is available as a PDF file. encourages all members of the aviation community, as well as the general public, to share their thoughts about the article and to make suggestions for improving those suggested procedures.

Reacting to the Threat

In-flight chemical and biological warfare agent threats can be divided into two categories, potential threats and active threats. The suggested procedures differ depending on where the threat is located in the aircraft, and whether the weapon has been activated. The highlights of the article are included below.

  • Cabin Threats without Activation
    Cockpit crewmembers should immediately don masks and goggles, and select 100% oxygen. Cover as much skin as possible with long sleeve shirts or your uniform jacket. Secure the device, then reduce altitude as much as possible. The device may be secured by covering and sealing the device as much as possible with a layer of plastic trash bags, dry blankets, more plastic, wet blankets, and then more dry blankets. Create as many barrier layers as possible between the agent and the cabin atmosphere.

  • Cabin Threats with Activation
    With the exception of slow-acting agents such as Anthrax, airborne exposure will rapidly generate sudden passenger sickness with symptoms such as choking, discoloration and fainting, blistering or convulsive actions. The cockpit crew should don mask and goggles, secure the cabin door and deny any entry from the cabin. Next, they should decrease cabin pressure (by raising the cabin altitude) as quickly as possible in order to evacuate and dilute the aerosol chemical agent. Additionally, selecting the coldest possible temperature will aid in minimizing agent aerosol dispersion. The crew should then land the aircraft as soon as possible.

  • Cargo Compartment Threats
    A reported threat in a cargo compartment should be dealt with much as one would deal with a cargo fire. Isolate the cargo bay by removing all sources of ventilation and shut off cargo heat sources. During descent, a positive outflow of pressure from the air packs will decrease the risk of chemical agents migrating from the cargo bays and into the cabin.

  • Diverting and Deplaning
    Certain actions may minimize the risk to the airport and surrounding communities. First, try to avoid overflight of populated areas during the approach and landing. Second, after landing seek a location downwind of any populated structures. Third, park diagonal to reported winds to allow deplaning only on the upwind side of the aircraft. Finally, keep all passengers and crew together and quarantined from non-emergency personnel.

Related Resources
Text of the complete article (PDF)
Overview of Chemical and Biological Warfare Agents
Dealing with Suspicious Mail and Packages
Tips for Traveling Under Increased Hijack Risks
Information on the 11 September 2001 Hijackings
Airport Security Issues

Suggested In-Flight Procedures for Chemical and Biological Warfare Threats -- Revised: 29 May 2008