An emergency situation occurs when the safety of the aircraft or individuals on board, as well as those on the ground, is at risk. In contrast, an abnormal situation arises when normal flight procedures are no longer applicable, but safety remains intact. These situations can develop from various factors, whether internal or external to the aircraft. For example, common triggers include:
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Fire on board the aircraft
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Failure or malfunction of aircraft components, such as engine issues or landing gear problems
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Fuel shortages or lack of other vital supplies
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Uncertainty about the aircraft’s position among the flight crew
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Deteriorating weather conditions
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Pilot incapacitation due to illness
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Damage to the aircraft from collisions, bird strikes, or severe weather
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Illegal activities, including bomb threats or hijacking.
When faced with an emergency or abnormal situation, continuing the flight as planned might become impossible. This could lead to several outcomes, such as loss of altitude, diversion to a nearby airport, or a forced landing.
To effectively handle these situations, operators must provide their staff and flight crew with an aircraft operating manual for each type of aircraft they operate. This manual should detail normal, abnormal, and emergency procedures, as well as information about the aircraft systems and an emergency or abnormal checklist (EAC). The design of this manual must adhere to human factors principles.
Operators are also required to maintain a comprehensive ground and flight training program, which must be approved by the State of the Operator. This program ensures that all flight crew members receive adequate training for their specific duties. Training should cover flight crew coordination and all types of emergency or abnormal situations caused by issues such as powerplant or airframe malfunctions and fires. Each crew member must understand their responsibilities and how they relate to the roles of other team members. This training is to be conducted regularly, as determined by the State of the Operator.
In real-world scenarios, immediate actions in response to certain emergencies, like fire or engine failure, are often performed from memory. After taking initial action, crew members will confirm their steps by consulting the EAC, which also outlines subsequent actions and considerations. Typically, the EAC is found in a separate volume from the Operations Manual, often referred to as the Quick Reference Handbook (QRH).
