Established steps in memorized, paper, or electronic format used in critical situations to aid the memory of those involved in a crisis.
For as long as there have been aircraft, there have been unexpected events that have necessitated methodical procedures in order to help ensure the safest possible outcome for both aircraft and crew. In aviation, emergencies are defined as situations in which immediate action by those involved is required in order to ensure the safety of a flight. In general, humans are ill equipped to deal consistently and effectively with emergencies.
A detailed set of guidelines or procedures for people to follow in the event of an emergency often helps to positively impact the emergency situation. These procedures have evolved from the relatively simple memorized procedures used by pilots of early aircraft to the relatively complex procedures used by a flight crew to deal with anomalies aboard large aircraft, such as the Boeing 777 and 747 heavy-transport aircraft.
Emergency procedures range from small-aircraft checklists for dealing the accidental opening of a cabin door during flight to large commercial airports’ detailed emergency plans for dealing with an incoming aircraft that has been rendered virtually uncontrollable. In the first case, the procedure may involve only the pilot of the aircraft, whereas, in the second scenario, emergency procedures would typically involve many people in several different organizations all engaging in a highly coordinated and rehearsed plan of action in order to effectively deal with the situation.
In the case of a small aircraft, it is recommended that pilots carry a set of emergency procedures checklists readily available to them in the event of an emergency. These checklists may be in paper or electronic format. Emergency procedures cover a variety of topics dealing with engine failures, in-flight fires, electrical failures, flight control malfunctions and others.
Emergency procedures checklists will often be color coded with red and white or red and black in order to command attention. These are then readily distinguishable from other procedures checklists. Often, certain emergency procedures are considered to be time-critical in order to effect a safe outcome. Such procedures, generally limited to three to five items, are called immediate-action items and are usually committed to memory. An instance in which such a procedure would be necessary is the failure of one engine of a twin- or single-engine aircraft immediately after takeoff. An event such as this leaves little time for a pilot to pull out a checklist and go over it line by line. Once the immediate-action items are attended to, the pilot can then methodically go through the remaining items.
Generally, the more complex the aircraft is, the more involved are the emergency procedures. In larger transport aircraft, more than one pilot is available to assist during crisis situations, and the delegation of responsibility at such times rests upon the pilot in command. In an emergency situation involving a multicrew aircraft, generally one pilot continues to fly and maintain control of the aircraft while the other pilot (or two) are freed up to focus on the emergency procedures.
In modern aircraft with electronic flight instrumentation there are often systems on board the aircraft that will assist the flight crew in diagnosing a problem and will provide the appropriate checklist on what is called a multifunction display (MFD) on the flight deck. This display highlights the appropriate checklist items and forces the crew to acknowledge each checklist item before proceeding to the next item. The MFD is a helpful feature during periods of high stress on the flight deck, because it makes it more difficult to forget or omit critical items, as can happen with paper checklists.
Larger aircraft, such as the Boeing 757 and 767, are equipped with an engine information and crew alerting system (EICAS), which immediately brings a fault diagnosis to the attention of the flight crew. The crew must then execute the pertinent emergency checklist in its entirety in a challenge-response format, in which the pilot who is not flying issues a challenge such as “throttle closed,” to which the appropriate crew member response is “throttle closed.” In this manner, each crew member is made aware of the checklist item and its completion status.
Emergency procedures also exist for the cabin crew, or flight attendants, and for passengers. All passengers are required by the Federal Aviation Regulations (FARs) to be briefed on these procedures by the cabin crew prior to flight. Research has shown that those passengers who listen to the preflight emergency briefing information are much more likely to survive an air accident than those who do not.
Airline cabin crew members are required to attend annual recurrent emergency procedures training. This training consists of a review of basic emergency and evacuation procedures for the particular aircraft the crew members fly. Most major airlines have or have access to aircraft cabin simulators, which can simulate an aircraft accident. In these scenarios, the cabin fills with a harmless smoke agent and the lights go down, as they would in an accident. The crew members are then evaluated on the accuracy and timeliness of their actions in getting people to safety.
In order to survive an air accident, the crew and passengers must be able to do three things successfully. First, they must survive the impact of the crash, if applicable. Second, they must evacuate the aircraft safely in a timely manner, especially in the event of a fire. Third, if the accident occurs away from an airport, they must survive the post-accident environmental conditions until they are rescued or until safety is reached. The first two items are often largely dependent upon how much attention was paid to the preflight safety briefing, whereas the third item depends upon previous training. Many organizations around the country specialize in postcrash survival training. A survival course varies from one day to one week or more and will cover a variety of subjects, including land navigation, rescue-signaling techniques, shelter construction, and food- and water-gathering techniques. Flights over remote areas are likely to carry emergency survival kits on board, which contain a variety of survival gear including signaling devices, drinking water, high-energy food, and first aid kits. Flights over water are required to carry flotation devices and life rafts, and training in their proper use is imperative. Most life rafts have an on-board emergency radio-locator transmitter and a visual strobe light to aid in aerial location, as well as sun shelters, sunscreen, water, and other survival gear.
The majority of aircraft accidents happen on the premises of an airport. If an aircraft accident occurs on or in the immediate vicinity of an airport, the occupants have a much greater chance of surviving the post-incident conditions, because all publicly certified airports have emergency action plans. There are approximately 5,400 public-use airports in the United States. Of these, approximately 670 are certified under Part 139 of Title 14 of the Code of Federal Regulations as certificated airports. The remaining airports, classified as non-certificated or general aviation airports, handle a relatively low volume of mostly light aircraft. If an airport has scheduled passenger or cargo airline service, it is required to be a certificated airport.
Certificated airports are rated according to classes A, B, C, D, or E, in accordance with the types of aircraft they serve. These classes, among other things, determine the amount and type of airport firefighting and rescue services (ARFF) the airports have. In the event of an aircraft accident, the emergency operations plan for the airport will go into effect. This plan is contained in, and is a preapproved part of, an airport’s certification manual. The plan is generally put into effect by an airport’s control tower, which will immediately notify the ARFF unit in the event of an accident. Other calls will be made in accordance with the emergency plan to such outside agencies as local law enforcement, ambulance services, hospitals, and coordinating fire and rescue departments in order to put them either on alert or into action, in accordance with the preapproved plan.
Every three years, certificated airports are required to conduct a live-fire training exercise under simulated accident conditions. In this exercise, the emergency action plan is put into effect, and all agencies react just as they would in an actual emergency. In this rehearsal, usually an aircraft is towed into a simulated crash position on the airport and costumed victims are situated in and around the aircraft, as they might be in an accident. Simulated crash victims are then extracted and treated, and fires are extinguished, allowing everyone involved a chance to identify areas of needed improvement in the plan. Each year, these same airports are required to go through the motions of the emergency plan in a “table-top” scenario, in which phone numbers are verified, calls are made according to the plan, and treating-unit capabilities are updated to ensure the currency of the plan.
On July 19, 1989, a series of events occurred in which well-rehearsed emergency procedures helped save many lives in an aviation event that might have been considered unsurvivable. On that day, United Air Lines Flight 232, a DC-10 wide-body transport aircraft, was flying passengers from Denver to Chicago when the airplane’s center engine disintegrated, causing the aircraft to lose all available hydraulic fluid. Because the flight controls on this type of aircraft are hydraulically operated, the aircraft was rendered virtually uncontrollable. Because the crew members had been trained in cockpit leadership resources (CLR), which taught them to utilize all available resources in order to save an aircraft under adverse circumstances, they were able to regain some control of the aircraft using differential thrust from the two remaining engines on each wing, even though there was no specific procedure for such an occurrence. This solution was made possible with the help of a passenger who happened to be a DC-10 pilot for United Air Lines. The cabin crew alerted the flight crew of this passenger’s availability, an event which might not have occurred had the crew not been trained in CLR. The aircraft subsequently crashed under limited control, broke apart, and then erupted in flames at the Sioux City, Iowa, airport. More than one-half of the occupants survived the ordeal, due, in large part, to the extraordinary efforts of the crew and to the fact that, very recently prior to the accident, the Sioux City airport had conducted its emergency action live-fire drill. This practice drill had enabled a much faster accident reaction time for rescuers.
A common theme throughout all aviation emergency procedures, whether they are on board an aircraft in flight or on the ground at an airport, is the importance of having structured, well-rehearsed and well-coordinated plans of action to follow. With these in place, human beings are much better able to perform under adverse circumstances, ensuring the minimum loss of life and damage to property.
Brown, Gregory N., and Mark J. Holt. “Emergency and Abnormal Procedures.” In Turbine Pilot’s Flight Manual. Ames: Iowa State University Press, 1995. An explanation of emergency and abnormal procedures from a pilot’s perspective and an excellent introduction to larger aircraft. Dee, Emily. Souls on Board: Responses to the United Flight 232 Tragedy. Siox City, Iowa: Loess Hills Press, 1990. A collection of stories from survivors of the runway tragedy in which many lives were saved by the effective application of emergency procedures. Wild, Thomas W. Transport Category Aircraft Systems. Casper, Wyo.: IAP, 1990. An in-depth examination of the various systems on board transport aircraft. Good illustrations and explanations make for a very informative text for those new to large aircraft. Information on the EICAS is presented throughout the text.
Airline industry, U.S.
Training and education