The Flight Test Errors and Deviations

Minor, Major and Critical Errors

An error is formally defined in the Flight Test Guides as a means an action or inaction by the flight crew that leads to a variance from operational or flight crew intentions or expectations.

Minor Error

An action or inaction that is inconsequential to the completion of a task, procedure or manoeuvre, even if certain elements of the performance vary from the recommended best practices.

Major Error

An action or inaction that can lead to an undesired aircraft state or a reduced safety margin, if improperly managed; or an error that does not lead to a safety risk, but detracts measurably from the successful achievement of the defined aim of a sequence/item:

Critical Error

An action, inaction that is mismanaged and consequently leads to an undesired aircraft state or compromises safety such as:

  • Non-compliance with CARS or non-adherence to mandated standard operating procedures;
  • Repeated improper error management or uncorrected and unrecognized threats that risk putting the aircraft in an undesired state or
  • Repeated major errors or the non-performance of elements prescribed in the Performance Criteria* that are essential to achieving the Aim* of a test sequence/item.

* defined in the applicable Flight Test Guide.

Comment: note especially the language used in regard to major or critical errors—safety.  If you commit an error that simply leads to reduced safety margins, but not a safety risk, you are heading for a 3 score, and that’s not bad.  Once a safety risk is displayed, or flying regulation is contravened, then you have committed a critical error and you are heading for 1 score, which is of course a fail.

Minor, Major and Critical Deviations

A deviation is formally defined in the Flight Test Guides as variance in precision with respect to a specified limit published for a test sequence/item, as a result of pilot error or faulty handing of the aircraft.

Minor Deviation

A deviation that does not exceed a specified limit:

Major Deviation

A deviation that exceeds a specified limit or repeated minor deviations without achieving stability:

Critical Deviation

A major deviation that is repeated, excessive or not corrected, such as:

  • Repeated non-adherence to specified limits;
  • More than doubling the specified value of a limit; or
  • Not identifying and correcting major deviations.

Comment: note that minor deviations place you in the 3 score column, while major deviations are in the 2 score column. Critical deviations are in the 1 score column and therefore constitute a fail. In practical terms, repeated exceeding published flight test tolerance will cause failure of a an exercise; a flight test exercise will also be assessed as failed if the candidate does not recognized that a deviation has occurred, or if they double the published tolerance for the exercise.

Further Reference:

Flight Test Guides