It’s your first real vacation in 2 years and the cabin loudspeaker comes on: “Is there a doctor on board?” Now what?

Ethically, if you can help, you should help, but there is no duty to an ill or injured passenger to compel your involvement. You can say nothing and go back to your book without legal consequences. However, you actually do want to help but are concerned about liability. In that regard, you can have considerable assurance.

The law that applies to responses to in-flight emergencies is the Aviation Medical Assistance Act (AMAA), covering all flights in North America, whether or not the carrier is a US company, and to US carriers wherever they fly. Under this, a “medically qualified” professional who acts in good faith and does not receive financial compensation receives the following protection: “An individual shall not be liable for damages in any action brought in a Federal or State court arising out of the acts or omissions of the individual in providing or attempting to provide assistance in the case of an in-flight medical emergency unless the individual, while rendering such assistance, is guilty of gross negligence or willful misconduct.”

If you are flying outside the US on a non-US carrier, the law of the country in which the airline is based will generally control, but these will typically offer Good Samaritan-type protection as well. There is an important limitation, though: You must wait to be asked to assist. This is because the members of the cabin crew, trained in First Aid, are the actual FAA-designated first responders.

FAA Advisory Circular 121-33B instructs flight attendants “to check the credentials of passengers holding themselves out as medical specialists.” You should also expect to be asked if you have been drinking and, if so, how much. You will then be given access to an enhanced medical kit. The flight crew also has a basic kit for First Aid that will be at your disposal, as well as an AED.

Your role will typically be to stabilize the ill or injured person until landing. You will not be held to a standard of definitive treatment unless the condition was one that could actually be fully dealt with while on the plane. The airline will have a contract with an SOS service for emergency medical support by a trained physician on the ground. However, only you can determine whether you can, consistent with the limitations of the AMAA, perform a task adequately even with that help.

Once you have begun treatment, your duty to remain in that role continues until the need ends or you are instructed to cease treatment by someone authorized to do so. Diverting the plane rests solely with the captain.

A contemporaneous note for yourself is always prudent. Do this as soon as possible while the facts are fresh in your mind and as an e-mail to yourself so that it will have a time and date stamp.

This article was written by Dr. MedLaw, a physician and medical malpractice attorney.