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Old 29th Sep 2018, 10:12
  #85 (permalink)  
chimbu warrior
 
Join Date: Jun 2001
Location: Paradise
Age: 68
Posts: 1,552
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I was curious about the “cloud break procedure”. Which sounds like (If I may be frank) bull****e, masked as technique.
It is neither BS nor technique.

As the above extract from the approach plate shows, the 3 degree profile brings the aircraft to the MDA (420 feet) at the MAP, which is 2.2 nautical miles from the threshold. Simple maths tells us that a 3 degree profile should have the aircraft at 700 feet when 2.2 nm from the threshold. As per the dashed lines (circled on the plan form view) there is then a visual segment (provided the aircraft is visual) of almost 1 mile to intercept the 3 degree profile at about 1.3 nm from the threshold.

It is unfortunate that the profile view of the procedure suggests that the descent from the MDA to the touchdown zone is coincident with the 3 degree path. It is not. If the aircraft descended on a 3 degree path from the MAP, it would very likely land short.

I'll let the NTSB do the investigating, but just point out that such procedures are not uncommon in this part of the world.
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