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Old 8th Sep 2013, 15:39
  #122 (permalink)  
RetiredF4
 
Join Date: Jun 2009
Location: Germany
Age: 71
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Tom Imrich
While authority views on this still may vary globally, and operator's policies still widely vary, and notwithstanding obsolete criteria still in TERPS and Pans-Ops, from a scientific and safety perspective, the issue of the potential minor momentary descent slightly below MDA(H) during a properly executed G/A is completely irrelevant. Both the FAA/JAA/Industry AWO HWG recognized this now over two decades ago (e.g., Theo Van de Ven's RLD paper) as well as even FAA's signed AC120-29A, which acknowledged this situation with language such as:
“Go-Around” Transition To A Missed ApproachWhen Using a DA(H) or MDA(H).
I did a search, and was not successfull to raise some substance to your quoted message.

Instead i found AC120-108 dated 01/20/2012, which seems to be newer than your reference.

http://code7700.com/pdfs/ac_120-108_cdfa.pdf

And it contains following quote, which looks quite reasonable.

f. Derived Decision Altitude (DDA). Pilots must not descend below the MDA when executing a missed approach from a CDFA. Operators should instruct their pilots to initiate the go-around at an altitude above the MDA (sometimes referred to as a DDA) to ensure the aircraft does not descend below the published MDA. Operators conducting approaches authorized by operations specification (OpSpec) C073, IFR Approach Procedures Using Vertical Navigation (VNAV), may use MDA as a DA.
Would you please explain?

Edit: Here is the mentioned specification (OpSpec) C073
http://www.faa.gov/documentLibrary/m...208900.183.pdf

Last edited by RetiredF4; 8th Sep 2013 at 17:15.
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