The reporter expressed a safety concern regarding the use of the abbreviation EST for Estimate in NOTAMs. The reporter stated that as this is an abbreviation which is in common use in aviation for Eastern Standard Time it is likely to result in the pilot misapplying the NOTAM times.
The reporter stated that the lack of clarity could lead to a potential safety issue as pilots misread the time as Eastern Standard Time when in fact it is still UTC.
Operator's response (Operator 1)
While it is acknowledged that some abbreviations may have multiple meanings, both domestic and international aircraft operating in Australian airspace are issued with NOTAMs utilising standardised abbreviations and formats as detailed by the International Civil Aviation Organisation (ICAO).
Specifically, NOTAMs are required to:
- Provide date-time information in coordinated universal time (UTC) when indicating the duration of a notice. Where timing is uncertain, the approximate duration is to be indicated using a UTC date-time group followed by the abbreviation "EST" (ICAO Annex 15, Appendix 6; ICAO Doc 8126, Chapter 6- Appendix A).
- Use the abbreviation "EST" to indicate estimate, estimated or estimation (ICAO Doc 8400).
As a signatory to ICAO, Airservices utilises these standard NOTAM formats to ensure clear and consistent communication with all aircraft operators.
Regulator's response (Regulator 1)
CASA acknowledges the response from Airservices Australia and has no further comment.