Wrong reaction to “Adjust Vertical Speed” RA
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Wrong reaction to “Adjust Vertical Speed” RA
Eurocontrol Safety Alert:- 2 June 2006 reminds pilots:-
N.B. “Adjust Vertical Speed” RAs always require a reduction of the vertical speed
Also see ACAS Safety Information.
- It is necessary to observe carefully the RA display when manoeuvring, bearing in mind that an "Adjust Vertical Speed" RA always requires a reduction of the vertical speed.
- All RAs are to be followed accurately, even if there is a discrepancy between RA and ATC clearance or instruction.
- There are repeated instances of pilots incorrectly executing “Adjust Vertical Speed” RAs.
- In some cases, this wrong reaction to this actually led to the deterioration of spacing between the aircraft.
- TCAS II is designed to generate an “Adjust Vertical Speed” RA instead of a stronger “Climb” or “Descend” RA, whenever possible.
- The objective is to solve a predicted risk of collision by a reduction of the current vertical speed, either in climb or in descent, while maximising compatibility with the ATC clearance. The reduction is associated with four different values: 0, 500, 1000 or 2000 fpm.
- RAs could occur when aircraft are in close proximity and the vertical speed of closure exceeds 1500 ft/min;
- This type of RA is mainly issued when an aircraft is climbing or descending to level-off 1000 ft from another aircraft. It reinforces the controller’s clearance and helps to ensure successful level-off at the cleared flight level.
- “Adjust Vertical Speed” RAs are the most frequent RAs triggered by TCAS II.
N.B. “Adjust Vertical Speed” RAs always require a reduction of the vertical speed
Also see ACAS Safety Information.