Yo-yo and sharp-turn angle - Guidelines

This document is aimed to describe the NM system tool for the detection of the Yo-Yo and sharp-turn angle flight plans (Turn) by aircraft operators (AOs) and flow management position (FMPs) using Network Manager systems. It also contains description of conditions for rejection of critical Yo-Yo and TURN profiles by IFPS.

A basic requirement for effective Air Traffic Flow Management is having predictability on both the capacity and the demand side. Analyses have shown that so-called "yo-yo profiles" and "sharp-turn angle profiles" (Turn) in flight plans are almost never flown.

All flight plans where a change of cruising flight level is done in a way that flight will have to initially descend and after that climb for a certain amount of feet (ITEM 15), and over a specified distance, are considered to be Yo-Yo flight plans. Similarly, all flight plans where the angle between two consecutive ATS routes/DCTs (based on ITEM 15) is greater than a specified value, are considered to be Sharp turn angle flight plans.

Yo-Yo and Turn profiles occur in flight plans for various reasons including wind component optimization, software limitations/bugs, airspace structure issues, compliance with airspace restrictions, company route maintenance limitations, avoidance of ATFM regulations, etc. Flight plan adherence is a joint responsibility of both pilots and air traffic controllers.

To support the reduction of unanticipated flight plans, and based on the ODSG/YYGD conclusions, NM enabled functionality for identification and rejection of Yo-Yo and sharp turn angle flight plans in operations.

The Document is a property of the Network Manager.


EUROCONTROL Yo-Yo and Sharp-Turn Angle Flight Plans Identification