Standard Operating Procedures (SOPs)

Standard Operating Procedures (SOPs)


Standard Operating Procedures (SOPs) in an ATC Unit are a specific set of procedures that specify how the unit’s controllers’ ATC responsibilities are to be co-ordinated. (EUROCONTROL EATM Glossary of Terms)

Within ATM, many types of procedure are rigidly applied, especially in regard to communication. However, with other types of procedure modification may be permitted to suit individual situations and personalities. Nevertheless, it should be remembered that standard procedures are based on long years of experience; if there is intent to modify an existing procedure, careful consideration must be given to ensure that unforeseen consequences do not result.

In Flight Operations, strict procedures are defined covering every aspect of flight deck activity and embracing normal, abnormal and emergency situations. This wide range of procedures and checklists is essential because of the large number of situations which can arise and the critical nature of some of these situations. Although these procedures are written down in checklists and quick reference handbooks, pilots must be able to perform certain vital actions from memory, referring to the written procedure later to confirm that correct action has been taken.

Flight Operations procedures have been defined after much research in order to ensure the most successful outcome from all reasonably likely circumstances. They are not discretionary and must be followed precisely. Failure to follow established procedures has been found to be a causal factor in many aircraft accidents and serious incidents.

Types of SOP

  • SOPs published by an aircraft manufacturer are designed to:
    • Reflect the manufacturer's flight deck design philosophy and operating philosophy;
    • Promote optimum use of aircraft design features; and,
    • Apply to a broad range of company operations and environments.

An aircraft manufacturer's SOPs can be adopted by a flying organisation without amendment, but are often used to develop customised company SOPs.

  • SOPs published within ATC Units specify how ATCOs responsibilities are to be co-ordinated.


Deviations from SOPs occur for a variety of reasons; intentional deviations and inadvertent deviations from SOPs have been identified as causal factors in many aircraft accidents and incidents.

Crew Resource Management (CRM) and Team Resource Management (TRM) are not effective without adherence to SOPs, because SOPs provide a standard reference for the ATC team and for the crew’s tasks on the flight deck. SOPs are effective only if they are clear and concise.

SOPs are the result of a careful process, often conducted over a period of many years, which considers all likely outcomes; deviation from a standard procedure may lead to an unexpected and unsafe outcome.

Typical Scenarios

  • An aircraft on approach to land is not stabilised due to high approach speed. SOPs require the aircraft to go-around in the event of an unstabilised approach but the pilot continues the approach in his desire to complete the schedule on time, risking collision with the ground (Controlled Flight Into Terrain (CFIT)) and severe aircraft damage.
  • An ATCO re-clears a climbing or descending aircraft to an intermediate level when the flight is already very close to that level; the pilot is unable to prevent the aircraft from overshooting the new cleared level.
  • A pilot or ATCO does not use standard phraseology in a message, resulting in the message being misunderstood by the recipient.

Contributory Factors

  • Inadequate knowledge or failure to understand a procedure (e.g., wording or phrasing was not clear, or the procedure was perceived as inappropriate);
  • Insufficient emphasis during training on adherence to SOPs;
  • Inadequate vigilance (e.g. fatigue);
  • Interruptions and distractions;
  • Task saturation;
  • Incorrect management of priorities;
  • Reduced attention (tunnel vision) in abnormal conditions or high-workload conditions;
  • Inadequate Crew Resource Management or Team Resource Management (TRM) (e.g., inadequate crew co-ordination, cross-check and backup);
  • Company/Unit policies (e.g., schedules, costs, optimisation of traffic);
  • Other policies (e.g. duty time);
  • Desire to get the job done;
  • Complacency and overconfidence.


Initial training provides the opportunity to establish the disciplined use of SOPs, and recurrent training offers the opportunity to reinforce that behaviour.

Management at all levels must insist on the proper use of SOPs.


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