Report of Large Lateral Deviation (LLD)

ATC facilities are required to report all Large Lateral Deviations (LLD) to the JASMA. An LLD is defined as a deviation of 10NM or more without ATC approval. Weather deviations approved by ATC, radar vectoring or change of route with ATC clearance are not recognized as LLDs.

Report of Large Longitudinal Error (LLE)

ATC facilities are required to report Large Longitudinal Errors (LLE) to the JASMA, if one of the following categories of longitudinal error in the criteria is observed:

  • Individual-aircraft (Time-based separation is applied)
     Pilot estimate varies by over 3 minutes from that advised in a routine position report
  • Aircraft-pair (Time-based separation is applied)
     Infringement of longitudinal separation standard based on routine position reports
  • Aircraft-pair (Distance-based separation is applied)
     Infringement of longitudinal separations standard, based on ADS, radar measurement or special request for RNAV position report

    The JASMA uses these LLD and LLE reports for the collision risk estimate and other purposes.