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Old 13th Jun 2006, 10:31
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MrGaspo
 
Join Date: Apr 2006
Location: Sydney
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Some food for thought

Regarding drift allowance in the holding pattern, was lucky enough to attend a lecture about twelve years ago by a guy ( whose name escapes me ) who was one of two blokes in the " Department " at the time whose job it was to design new approaches. He was quite positive about his views on drift correction in the holding pattern and that was that " triple the drift " for a 2 min pattern and " double the drift " for a 3 min pattern were not approved procedures.
In correcting for a wind that blows you into the pattern what you are actually doing on the outbound leg is purposely flying the aircraft wide and in doing so you could leave the protection of the surveyed area with regards to obstacle clearance.

ENR 1.5 3.4.1 states;

" When flying the standard holding pattern , an aircraft MUST;

a. follow the prescribed track inbound to the holding point;

b. execute a 180 turn in the direction specified , SO AS TO FLY
OUT-BOUND A TRACK PARALLEL TO THE INBOUND TRACK;

c. continue outbound to the earlier of the time, or the DME limit
specified ; and

d. execute a 180 turn to realign the aircraft on the inbound track."

Paragraph "b" is quite explicit , you MUST fly the outbound leg so as to parallel the the inbound track , no mention of "triple" or "double" the drift. It was made clear to all at the lecture that all you are permitted to do on the outbound leg is apply the known drift in order to keep the leg parallell

Perhaps someone involved at this level of approach design today could be found to comment.

Regards Mr Gaspo
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