The reporter observed that there is no written standard for the FAA commonly used phrase; 'report a ...

Narrative:

We have a recurring area of confusion between controllers and pilots. To my knowledge; and to the knowledge of our ATCT supervisor; there is no written documentation by the FAA of the common phrase 'report a 3 mile [left/right] base.'when ATC uses this; they want the pilot to enter an extended base leg (extending perpendicular from the runway approximately 3/4 mile from the runway threshold); and report 3 miles before turning final. When some pilots hear this; however; they will widen the entire pattern by 3 miles; and set up as if they are going to turn a 3 mile final; which sometimes messes up the sequence for ATC.I saw the FAA successfully resolve the final vector 'direct to the FAF' issue on instrument approaches that callback noted several years ago; and this is a similar system issue that should be addressed.

Original NASA ASRS Text

Title: The reporter observed that there is no written standard for the FAA commonly used phrase; 'Report a 3 mile left/right base;' and that the phrase is sometimes misunderstood by pilots; resulting in a pattern that alters aircraft spacing; separation; and sequencing.

Narrative: We have a recurring area of confusion between controllers and pilots. To my knowledge; and to the knowledge of our ATCT supervisor; there is no written documentation by the FAA of the common phrase 'report a 3 mile [left/right] base.'When ATC uses this; they want the pilot to enter an extended base leg (extending perpendicular from the runway approximately 3/4 mile from the runway threshold); and report 3 miles before turning final. When some pilots hear this; however; they will widen the entire pattern by 3 miles; and set up as if they are going to turn a 3 mile final; which sometimes messes up the sequence for ATC.I saw the FAA successfully resolve the final vector 'direct to the FAF' issue on instrument approaches that callback noted several years ago; and this is a similar system issue that should be addressed.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1397717
Time
Date	201610
Place
Locale Reference	ZZZ.Airport
State Reference	US
Aircraft 1
Make Model Name	No Aircraft
Person 1
Qualification	Flight Crew Flight Instructor Flight Crew Multiengine Flight Crew Instrument
Experience	Flight Crew Last 90 Days 10 Flight Crew Total 2300
Events
Anomaly	ATC Issue All Types Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Deviation - Track / Heading All Types

The reporter observed that there is no written standard for the FAA commonly used phrase; 'report a 3 mile left/right base;' and that the phrase is sometimes misunderstood by pilots; resulting in a pattern that alters aircraft spacing; separation; and sequencing.